DECONTAMINATION OF PESTICIDE RESIDUES ON FRUITS AND VEGETABLES
The impact of household preparation or industrial processing to reduce the pesticide residue levels on raw agricultural commodities (RACs) is considerable as they normally decline the residues. These kinds of processung strudies are intended: To provide info around the transfer of residues in the RAC to the processed merchandise, as a way to calculate reduction factor or concentration variables; To enable and more realistic estimate to become created of the dietary intake of pesticide residues; To establish MRLs for residues in processed merchandise where needed, in line with needs of national regulatory authorities or international requirements. Preferably, RAC samples used in processing research must contain field treated quantifiable residues as close as you possibly can towards the MRL, to ensure that measurable residues are obtained, and transfer variables for the numerous processed commodities could be determined. A transfer element provides the ratio from the residue concentration in the processed commodity to that inside the RAC. For instance when the residue concentration is 0.5 mg/kg in olives and 0.two mg/kg in olive oil, the transfer issue is 0.2/0.5=0.four. A factor 1 (= concentration issue) indicates a concentration effect from the processing procedures. Enhancing the residues either by escalating the application rates, shortening the pre-harvest interval (PHI) or spiking the RAC with the active ingredient and its metabolites in vitro isn't, as and rule, desirable. Spiking is only acceptable in the event the RAC residues may be shown to consist only of surface residues. Nonetheless, in some cases, especially exactly where residues in the RAC are close to the analytical limit of determination, field treatment at exaggerated prices or shortened PHIs is advisable to get enough residue levels for the processing studies.
The initial step in household or industrial food processing may be the preparation of food making use of a variety of mechanical processes, including removing damaged or soiled things or components of crops, washing, peeling, trimming or hulling. This usually leads to important declines inside the volume of pesticide residues inside the remaining edible portions (Petersen et al., 1996; Celik et al., 1995; Schattenberg et al., 1996).
WASHING
Household washing procedures are normally carried out with operating or standing water at moderate temperatures. Detergents, chlorine or ozone can be added for the wash water to improve the effectiveness in the washing procedure (Ong et al., 1996). If needed, numerous washing measures can be performed consequently. The effects rely on the physiochemical properties of the pesticides, such as water solubility, hydrolytic price continuous, volatility and octanol-water partition coefficient (Pow), in conjunction using the actual physical place on the residues; washing processes bring about reduction of hydrophilic residues which are located around the surface in the crops. Furthermore, the temperature from the washing water and the sort of washing has an influence on the residue level. As pointed out by Holland et al. (1994), hot washing along with the addition of detergents are a lot more powerful than cold water washing. Washing coupled with gentle rubbing by hand beneath tap water for 1 min dislodges pesticide residues substantially (Barooah and Yein, 1996). Systemic and lipophilic pesticide residues usually are not removed considerably by washing. Table (1) shows examples of the effects of washing on the residue levels of various pesticides applied to fruits and vegetables.
PEELING
The outer leaves of vegetables usually include residues of pesticides applied for the duration of the expanding season. Consequently, peeling or trimming procedures minimize the residues levels in leafy vegetables. Peeling of root, tuber and bulb vegetables with a knife is typical household practice. Several examples show that the majority of the residues concentration is situated in or around the peel. Peeling in the RACs may possibly eliminate greater than 50% of the pesticide residues present within the commodity. Thus, removal in the peel achieves virtually comprehensive removal of residues, so leaving tiny within the edible portions. This really is specifically important for fruits that are not eaten with their peels, like bananas or citrus fruits. Reynolds (1996) showed that peeling or trimming of carrot decreased the residues of chlorfenvinphos, primiphos-methyl, quinalphos, triazophos resulting a transfer factor of 0.two. Nonetheless, the peel from commercial peeling processes can be utilized as animal feed or for the production of essential oils (citrus) or pectin (citrus, apple etc.). For such industrial processes, it is essential to comprehend that specially non-systemic surface residues are usually concentrated in the peel. For systemic pesticides, peeling may possibly not be as efficient as shown by Sheikhorgan et al (1994). Following application of thiometon on cucumbers, no reduction of residue levels might be detected within the peeled cucumbers. Beneath the Codex Alimentarius, as in other international requirements, MRLs refer for the entire fruits, which can be suitable for assessing compliance with GAP. These MRLs are of restricted significance, even so, in assessing dietary exposure to pesticides from fresh fruits, that are peeled (Holland et al.,1994).
COOKING Cooking procedures at distinct temperatures, the duration in the process, the volume of water or meals additives, as well as the sort of system (open or closed) might have an effect on the residue level. Normally, residues are lowered for the duration of the cooking approach by volatilization in open systems or by hydrolysis in closed systems. In any case, adding cooking liquid dilutes the residues. Many studies have been reported around the dissipation of pesticides in crops during cooking. Moreover for the research summarized in table 1 the behavior in the organophosphorus pesticides chlorfenvinphos, fenitrpothion, isoxathion, methidathion and prothiophos throughout cooking was examined by Nagayama (1996) with green tea leaves, spinach and fruits. These pesticides decreased during the cooking approach corresponding for the boiling time. In accordance with their water solubility, some pesticides have been translocated from the raw materials into the cooking water. However, the pesticide remained in the processed meals based on their octanol-water partition coefficient, which is an indicator of hydrophilic or lipophilic properties on the compound. In exceptional cases, cooking processes could trigger pesticide degradation, yielding a reaction product of toxicological significance. For e.g., daminozide is degraded to UDMH (1, 1-dimethylhydrazine), that is significantly much more potent than the parent compound (Leparulo-Lofus et al.,1992). An additional example is the formation of ETU (Ethylenethiourea) from EBDCs (Ethylene bisdithiocarbamate) fungicides like mancozeb, during heating processes (Petersen et al., 1996).
Dipping in chemical solution Sodium chloride solution is largely used to decontaminate the pesticide residues from different fruits and vegetables .there are several research to prove the efficacy of salt water washing to dislodge the pesticides from crops. Within this procedure, sample of chopped fruits and vegetables is put in a beaker containing 5% sodium chloride solution. After 15 minutes the plant samples are gently rubbed by hand in salt solution and alt water is decanted. The examples in the impact of salt answer therapy on the residue levels of different pesticides applied to vegetables have already been shown in table 1. Kumar et al (2000) reported that dipping of green chillies in 2% salt remedy for ten minute followed by water wash prove to become effective, facilitating the removal of 32.56 and 84.21% residues correspondingly at 0 and 5 days after spray of triazophos (700g a.i./ha) although the acephate residues have been removed to an extent of 78.95% at zero day. Following exact same approach Kumar et al (2000) observed the 90.56 and66.93% reduction correspondingly on 0 and five days soon after spraying of cypermethrin in chillies. Dip remedy of fruits in NaCl resolution, HCl, acetic acid, NaOH solution, potassium permanganate removed 50-60% of surface residues of synthetic pyrethroids in comparison to 40-50% removal by hydrolytic degradation with NaOH (Awasthi, 1986b). Water answer of NaOH, acetic acid potassium dichromate and soap solution used as decontaminating agents for tom . The therapy of fruits with 2% tamarind resolution dip for five minute followed by tap water wash and steam cooking for ten min. was discovered to get rid of the residues of monocrotophos, carbaryl and fenvalerate to an extent of 41.81, 100 and 100% respectively. Treatment with 2% salt answer was equally powerful. Dip therapies in the brinjal fruit wioth water, sodium chloride, HCl solution, acetic acid resolution or potassium permanganate remedy were all located to eliminate 30-33% in the residues of fenvalerate, permethrin, cypermethrin and deltamethrin; NaOH remedy 40-45% and Teepol (a detergent) remedy 50-60%. The effect of washing in lowering the residues decreased progressively in the second and third harvests. A lot of experiments had been carried out with all the 3 frequent household preparations viz. washing with water, salt water washing and cooking to asses their relative efficiencies in reducing the pesticide residues in distinct vegetables. The outcomes have already been summarized in the following table.
Table: Effect of washing, salt water washing and cooking on pesticide residue levels.
Crop Pesticide % of Residue dislodged *ResultReference Washing with waterSalt water washing Cooking CauliflowerMethamidophos41-4846-4746.94 -53.54Largest reduction was brought about by cooking. Jacob and Verma (1990)
Okra Methamidophos 64-72 19-58 58-64Washing with water could remove maximum residues indicating its maximum solubility in water although each of the processes reduced down the TMRL values.Jacob and Verma (1990)
CauliflowerAlpha-cypermethrin 7-38_ 12-17Washing was discovered to become more efficient than cooking possibly due to the thermal stability of cypermethrin.Malik et al (1997)
Cabbage
Chlorpyriphos
Quinalphos
38
41
52.13
56.50
54.three
55With the three processes residues were lowered to some extent. They can not lessen the residue below the MRL. Thus a waiting period of a minimum of 1 and two weeks, respectively, was suggested irrespective of washing cooking for quinalphos and chlorpyriphos on cabbage. Nagesh and Verma (1997)
Cow pea Metasystox
Carbalyl 84.3
87.five 86.four
88.7 83.four
80.8Only boiling from the pod samples could decontaminate the residues present of surface or inside the tissue towards the extent of secure limits by 10th day of treatment.Dikshit et al (1984)
Cauliflower Malathion 60 70 80Cooking was found to be most successful and lowered the TMRL value from one week to zero days.Jacob and Verma (1989)
Bhindi Quinalphos 61.84-64.35 43-53 78-82 Both washing with water and salt water washing brought down the residues under the MRL at zero days, cooking also did this resulting maximum reduction of residues. Jacob and Verma (1985)
Cabbage Malathion
Carbaryl
Pyrethroids 64.60
75.40
22.06 (av.) -
-
-
83.97
89.62
56.72 (av.) The extent of decontamination was larger on account of cooking when compared with washing for all insecticides. Bhatia and Verma (1994) Leaves and curds of cauliflower heads of cabbage and pods of Indian colza
Green beans
Methamidophos
DDT
Malathion
Carbaryl
65.71-77.67
71
96
52
-
-
-
-
80-88.88
52(cooked) 66 (stress cooked)
99(cooked) 99(p.cooked)
77cooked 69(p.cooked)
Cooking dislodges maximum residues.
Water wash removed maximum DDT residues whereas cooking is effective to take away malathion and carbaryl residues.
Dikshit et al (1986)
Elkins et al (1968)
From the above table it can be stated that cooking is most powerful to decrease the residues of different pesticides from different vegetables although in some circumstances washing with water was located to become efficient to reduce the initial residues of pesticides and it has been discovered that with all the ageing of residues or with the improve within the sampling days more than therapies the impact of washing decreases to get rid of the toxicant to the same extent as that of samples collected quickly right after spray where boiling or cooking is identified to be powerful. One of the attainable purpose for high percentage of removal of toxicant from quickly collected samples as the majority of the residues are present on the surface from the samples and hence it's very simple to get rid of by simple washing as observed by Dikshit et al (1984,86) Elkins et al (1968), Bhatia and Verma (1994) and Malik et al (1998). Together with the time elapsed the residues are migrated inside the deeper tissues or strongly adhere on the rough surface of some vegetables. Additionally, the washing can not lessen the residues to the protected level as in comparison with boiling. You can find some studies exactly where each of the three culinary processes proved to be inefficient to minimize the residues beneath the MRL value. Based on Jacob and Verma (1991) residues of quinalphos in the treated cauliflower crop could be lowered only to some extent by various residence processing strategies like washing and cooking. Nagesh and Verma (1997) opined that the inefficiency of the house processes for decontaminating the treated cabbage may be as a result of powerful adsorption properties of quinalphos and chlorpyriphos.
Impact of household preparation for decontamination of pesticide multiresidues in fruits and vegetables Low levels of pesticide residues had been detected in 97(40%) of mt 243 samples analyzed right after following normal household washing, peeling and cooking procedures. The number of samples containing detectable residues dropped to 47(19%) soon after household preparation. These final results indicate that residue level in most commodities are substantially reduced soon after household preparation (Schattenberg et al., 1996) Ramesh and Balasubramanian (1999) performed a study with fruits and vegetables collected from Chennai nearby markets and fortified with known concentrations of numerous pesticides followed by decontamination study with various household preparations like washing, cooking , peeling resulting 65-95% decontamination of pesticide residues at different stages of 512 raw industry samples analyzed, the organochlorine and organophosphorus pesticides present in the 12 samples have been removed resulting in residues effectively below the toxicologically acceptable limits. A brief rinse in tap water reduces pesticide residues on several sorts of make (Krol et al., 2000). Rinsing removed residues for nine on the twelve pesticides studied. Among captan, chlorothalonil, iprodione, vinclozolin, endosulfan, permethrin, methoxichlor, malathion, diazinon, chlorpyriphos, bifenthrin and DDE; residues of vinclozolin, bifenthrin and chlorpyriphos weren't removed. This study confirms that the water solubility of pesticides will not play a substantial role in the observed decrease. The majority of pesticide residues appear to reside around the surface of generate exactly where it really is removed by the mechanical action of rinsing. Earlier research on the effects of industrial and property preparation on pesticide residue in fruits and vegetables have been summarized by Zabik (1987). The early research showed residue reduction to be substantial, with percentage reduction of chlorinated hydrocarbons ranking from 50 to 99+ % for commercial preparation and from 14 to 99+ % for home preparation with all the exception of parathion in spinach and broccoli, commercvial and property prewparation substantially lowered organophosphate residues, using the reduction usually being within the higher 80 or 90% range. Carbamate residues were reduced by 58 to 99+ % when the vegetables have been commercially processed but only by 11 to 92% in home preparation. A recent study in Korea supports these earlier studies (Lee and Lee, 1997). These authors discovered that 45% in the organophosphate residues had been eliminated when the foods were washed in water, 56% with detergent washing, 91% with peeling, and 51% with blanching or boiling.
Methods of multiresidue analysis of pesticides in fruits and vegetables Analysis by gas chromatography
Nakamura et al (1994) developed a approach for multiresidue evaluation of 48 pesticides (20 organophosphorus, 7 organochlorine, 14 organonitrogen and 7 pyrethroid pesticides ) permitted in Japan on the basis of capillary GC after extracting the pesticides with nacetone from vegetable and fruit samples or with acetonitrile from lipid containing crops followed by reextraction into ethyl acetate (test remedy). Organophosphorus pesticides have been directly determined by GC-FPD. Organonitrogen pesticides had been determined by GC-FTD (GC-NPD) following clean up by silica gel chromatography. Organochlorine and pyrethroid pesticides were measured by GC-ECD soon after clean up by florisil column chromatography. Recoveries for ten crops at fortification levels of 0.05-0.25 ppm were 42.5-128.5%. the detection limits were 0.001 ppm for organophosphorus and organochlorine pesticides and 0.01 ppm for organonitrogen and pyrethroid pesticides.
A multiresidue strategy was employed by Dejonckheere et al (1996) for determination of organochlorine, organophosphorus and organonitrogen pesticides in vegetables and fruits which have been extracted with acetone followed by liquid-liquid partitioning with water:apolar pesticides in petroleum ether phase, polar pesticides extracted from aqueous layer with dichloromethane and analyzed by gas chromatography with electron capture (GC-ECD), flame photometric (GC-FPD) and thermoionic certain (GC-TSD) detection.
The method used for multiresidue determination of 52 pesticides such as organophosphorus, organochlorine, organonitrogen, certain pyrethroids and dithiocarbamate pesticides in vegetables and fruits was described by Dogheim et al (1999) using gas chromatography. Samples had been extracted with acetone followed by partitioning with hexane and dichloromethane and estimated by GC-ECD and GC-NPD. Dithiocarbamates were digested in mixture of concentrated HCl, SnCl2 and water for evolution of CS2 which can be collected in an ethanolic answer of copper acetate and diethanolamine to type a yellow complex. The absorbance of yellow product was determined spectrophotometrically at 435 nm. The average recoveries and CVs from the 52 pesticides have been 72-118 and 1-20%, respectively at the spiking levels of 0.01-1 ppm. A similar type of strategy was also described by Kole et al (1998).
Krol et al (2000) used a multiresidue process for determination of 12 pesticides in vegetables exactly where samples have been extracted with two propanol and petroleum ether followed by washing with distilled water 3 times. Final analysis in the samples was performed by GC-ECD, FPD, XSD and/or ELCD.
Ramesah and Balasubramanian (1999) described a strategy to figure out organochlorine, organonitrogen and organophosphorus pesticides in vegetables and fruits following extraction with 2-propanol and petroleum ether by mechanical shaker followed by partitioning with distilled water and column cleanup over florisil for OC and OP pesticides. For organonitrogen pesticides the extraction was accomplished with acetone followed by partitioning with 10%NaCl and ethyl acetate and column clean up more than silica gel. organochlorine, organophosphorus and organonitrogen compounds were analyzed by GC-ECD,GC-FPD and GC-NPD, respectively.
Using GC-ECD, the efficiencies of acetonitrile and acetone to extract the 8 pyrethroids from six fruits and vegetable samples were compared by Pang et al (1997). The extraction efficiency of acetone was competitive with that of acetonitrile for the six fruit and vegetable samples. The ruggedness tests demonstrated further that the proposed approach is straightforward, accurate with excellent precision and suitable for multiresidue analysis of pyrethroid in different agricultural items.
Organophosphorus and organochlorine pesticide residues from fruit and vegetables by capillary GC with electron capture detector (ECD), nitrogen phosphorus detector (NPD), flame photometric detector (FPD) within the sulfur and phosphorus modes, and mass spectrometry detector (MSD) in chosen ion monitoring (SIM) mode had been determined by Torres et al (1995) following extraction by Matrix Strong Phase Dispersion (MSPD) resulting recoveries of 41-108% with relative SD of 2-14% inside the conc. variety 0.5-10 g/liter in oranges, lemons, grapefruit, pears, plums, lettuces and tomatoes. A multiresidue method as described by Sannino et al (1995) for quantitative determination of 39 organophosphorus compounds (parent pesticides and their major metabolites) in 7 fatty processed foods based on automated gel permeation chromatography with a Biobeads SX3 column along with a methylene chloride-cyclohexane (15 + 85) eluant after extraction with methylene chloride. Organophosphorus compounds are quantitated by GC-FPD employing OV-1701 and DB-5 columns. Average recoveries from samples fortified at 0.025-1 mg/kg ranged from 50.6% for dichlorvos to 185% for malaoxon. Determination limits have been among 0.005 and 0.040 mug/mL. Benefits were confirmed by gas chromatography/mass spectrometry with selected-ion monitoring. Gas chromatographic circumstances for separation and identification of the compounds have been chosen employing two capillary columns of different polarities and two detectors, ECD and NPD for multiresidue quantitative determination of 37 pesticides in fruit and vegetables and to study the efficiency of gel-permeation chromatography clean-up soon after ethyl acetate extraction (Balinova,1999). Trova et al (1999) performed liquid chromatographic determination of pesticide residues (such as azinphos-ethyl, azinphos-methyl, carbaryl, diflubenzuron, dinocap and teflubenzuron) in vegetables right after extraction employing an ethyl acetate/n-hexane solvent program instead on the broadly employed methylene chloride. Recoveries as essential by 'Guidelines for residues monitoring within the European Union' have been observed; the new solvent method may be deemed as an alternative to halogenated compounds, dangerous for their toxicity and damaging for their environmental behaviors, in extraction of HPLC-determinable active compounds. A wide range screening technique was proposed by Gelsomino et al (1997) for multiresidue analysis of 77 pesticides (12 organohalogens, 45 organonitrogens, 11 organophosphorus and 9 pyrethroids) in agricultural products making use of gas chromatography equipped with extended, narrow-bore fused-silica open-tubular columns and electron-capture detector (ECD). Residues had been extracted with acetone followed by dichloromethane partitioning and gel permeation chromatographic clean up. Recoveries in the majority of pesticides from spiked samples of carrot, melon and tomato at fortification levels of 0.04-0.10 mg/kg had been 70-108%. Limits of detection have been significantly less than 0.01 mg/kg for ECD. Beena et al (2002, 2003) carried out monitoring of vegetable samples adopting a multiresidue analytical technique employing GC-ECD and GC-NPD systems with capillary columns. Ueno et al (2003) studied an efficient and dependable multiresidue technique for figuring out 52 nitrogen- and/or phosphorus- containing pesticide residues within a large quantity of vegetable samples in which samples have been extracted with acetonitrile, as well as the separated acetonitrile layer was purified by gel permeation chromatography that divided the pesticide eluate into 2 fractoions, the pesticide fractions have been respectively purified by a 2-step minicolumn cleanup, the second fraction via silica gel minicolumn; 1st fraction by way of the tandem minicolumn (florisil minicolumn, inserted on silica gel minicolumn) which was eluted with acetone-petroleum ether (3+7). The combined eluate was subjected to dual column gas chromatography with nitrogen-phosphorus and flame photometric detection. Recoveries of 52 pesticides from fortified samples ranged from 72 to 108% with relative regular deviations of 2-17%, except for the recoveries of methamidophos and chorothalonil. The detection limits from the pesticides had been satisfactory (0.001-0.009 mg/kg) for monitoring of pesticide residues in vegetables. Menkissoglu et al (2004) performed a study from the matrix induced impact for 16 widespread pesticides, most often identified in monitoring studies in tomato pepper and cucumber, utilizing a easy multiresidue method with GC-ECD or NPD, with out a previous cleanup step. Anomalously high GC responses and subsequently quite higher recoveries for a number of pesticides in the extracts have been obtained by a traditional calibration with pesticide resolution in ethyl acetate. A quicker, significantly less effective, environmentally safer supercritical fluid extraction (SFE) approach was evaluated by Garcia et al (1996) over conventional sonvent extraction methods for the extraction of imidacloprid, methiocarb, chlorpyrifos, chlorothalonil, endosulfan-1, endosulfan-2 and endosulfan sulfate, from pepper and tomato employing vegetable sample: anhydrous magnesium sulfate (5:7) mixtures to carryout the extraction with supercritical CO2 and HPLC/DAD,GC/ECD and GC/FPD for evaluation. The selected SFE situations had been 300 atm, 500C, 200l of methanol static modifier, 1 minute static time, and dynamic extraction with 15 ml of CO2 and collection in three ml of ethyl acetate. Except for imidacloprid, which was not recovered beneath any from the assessed circumstances, pesticide recoveries had been higher than 80%. A simplified approach is described by Chaput (1987) where reverse phase liquid chromatography was utilized with post column derivatisation and fluorescence detector to determine 7 N-methyl carbamates (aldicarb, carbaryl, carbofuran, methiocarb, methomyl, oxamyl and propoxur) and three connected metabolites in fruits and vegetables after extraction of the sample with methanol followed by gel permeation chromatography (GPC) or GPC with on-line Nuclear-celite clean up for crops with high chlorophyll and/or carotene content (e.g. cabbage and broccoli). Recovery information have been obtained by fortifying 5 diverse crops (apples, broccoli, cabbage, cauliflower and potatoes) at 0.05 and 0.five ppm. Recoveries averaged 93% at both fortification levels. The coefficient of variation of the method at both levels is
Estimation by GC-MS/LC-MS Because the mass spectrometer is capable of reaching higher levels of molecular specificity as when compared with the classic GC detectors and may be programmed to look for several hundred target ions, GC/MS will be a promising strategy for regulatory agencies to discover for monitoring pesticide residues in daily food provide (Cheng et al, 1994). Cheng et al (1994) reported a multiresidue strategy utilizing gas chromatography /mass spectrometry/selected ion monitoring (GC/MS/SIM) for the determination of captan, chlorothalonil, dichlorovos, dimethoate, EPN, phorate, primiphos-methyl and prothiophos residues in fruits and vegetables. Recoveries have been among 46 and 108% at the 0.five mg/kg fortification degree of each and every pesticide in apples, cabbages, cucumbers and grapes. Coefficients of variation have been between 0.7 and 19%, with an typical of 7.5%. The estimated limits of detection from the pesticides in the crops have been 0.1-0.05 mg/kg, except that captan had limit of detection within the crops higher than 0.5 mg/kg. A approach according to solid-phase extraction using a carbograph 1 cartridge and reverse phase liquid chromatography /mass spectrometry (LC/MS) with an electrospray (ES) interface was described by Corcia et al (1996) for measuring traces of N-methylcarbamate insecticides in ten different varieties of fruits and vegetables .twelve carbamates added to vegetable supplies have been extracted with methanol making use of a homogenizer followed by filtration , an aliquot from the homogenate equivalent to 5 g in the vegetable material was suitably diluted with water and passed via a 1 Carbograpg 1 extraction cartridge. Carbamates have been eluted by passing via the cartridge 6 ml of a CH2Cl2/CH3OH (80:20 v/vegetables) mixture. Recovery from the analytes was much better than 80%, irrespective of the kind vegetable matrix to which the analytes were added. A approach utilizing completely automated solid-phase extraction (SPE) sample cleanup and on-line liquid chromatographic evaluation with UV and fluorescence detection in tandem for determination of carbendazim and thiabendazole in various crops was reported by Hiemstra et al (1995). A total of 199 pesticides have been determined by Fillion et al (1995) in fruits and vegetables utilizing acetonitrile as extracting solvent and a miniaturized charcoal-celite column cleanup followed by gas chromatography with mass-selective detection in selective-ion monitoring mode. Carbamates have been analyzed by liquid chromatography with post column reaction and fluorescence detection. Recovery data had been obtained by fortifying 3 matrixes (pear, carrots and bananas) at 0.1-0.five ppm. Blasco et al (2004) employed a quantitative matrix solid-phase dispersion and liquid chromatographyatmospheric stress chemical ionization mass spectrometry (LC-APCI-MS) approach for the simultaneous analysis of dithiocarbamates and their degradation products in crops. Typical recoveries varied from 33 to 109%, and relative normal deviation was between four and 21% with limits of quantification ranged from 0.25 to two.five mg/kg. A multiresidue evaluation for the determination in the 101 pesticides, like organophosphorus, organochlorine and nitrogen-containing pesticides, in crops by gas chromatography with mass selective detector was performed by Chun et al (2003). Evaluation was performed inside the selected-ion monitoring mode. Samples had been spiked with pesticides at 0.1-1.0 mg/kg. The recoveries of 90% on the pesticides wee between 70 and 110%; even so, the recoveries of acephate and folpet had been extremely poor, i.e.,
Proposed plan of function Standardisation of multiresidue analytical strategies of pesticides
Analytical standard of chosen pesticides belonging to distinct classes viz. OC (HCH (?,?,? and ? isomer), DDT (OP-DDT, PP-DDT, op-DDD, pp-DDE), Endosulfan (?,? and endosulfan sulfate) and dicofol);OP(Dimethoate, Malathion, Methyl parathion, Chlorpyriphos, Quinalphos, Triazophos, Phosphamidon,Dichlorvos Metasystox and Monocrotophos) and Synthetic Pyrethroids (Cypermethrin, Deltamethrin, Fenvalerate) for monitoring and decontamination studies have already been collected from different sources as follows: Sl No.Name in the pesticidesPurity %Source Organochlorine 1?-HCH99.5EPA 2?-HCH99.5EPA three?-HCH99.5EPA 4?-HCH99.5EPA 5OP-DDT99.7EPA 6PP-DDT99.7EPA 7OP-DDD99.7EPA 8PP-DDE99.7EPA 9?-endosulfan99.0Excel 10?-endosulfan99.0Excel 11endosulfan sulfate99.0Excel 12Dicofol96.0Bayer Organophosphorus 13Dimethoate96.5UPL 14Malathion97.3UPL 15Methyl parathion98.5Bayer 16Chlorpyriphos99.7Denocil crop protection Ltd. 17Quinalphos95.6Sandoz Ltd. 18Phosphamidon93.9Bayer 19Triazophos40.8Aventis Crop Science 20Monocrotophos77.0UPL 21Dichlorvos- 22Metasystox- Synthetit pyrethroids CCSRI Cypermethrin,99.0CCSRI Deltamethrin
Fenvalerate99.0
99.0CCSRI
4.1.1Stock normal resolution: Stock standard answer of different pesticides are to be ready in distilled hexane/acetone and diluted suitably to serve as operating normal and to verify the mindividual chromatographic peaks for their suitability for multiresidue evaluation. 4.1.2Preparation of mixed common solytion: from the individual normal options a mixed normal resolution is usually to be prepared for strategy mdevelopment and decontamination research. 4.1.3Extraction and cleanup In the assessment of literature 3 strategies proposed by Kole et al (1998), Nakamura et al (1994) and Obana et al (2001) happen to be chosen to conduct the extraction and cleanup procedure where each the liquid-liquid along with a solid-phase extraction with a cartridge column will be in comparison with create a quick,easier and cost-effective strategy to screen a wide selection of pesticides. 4.1.4Estimation of pesticide multiresidue A gas chromatograph coupled with an Electron Capture Detectore (ECD) and Nitrogen Phosphorus Detector (NPD) is to be employed for estimation of the pesticide residues. The operating conditions may also be studied as stated within the chosen three methods. four.1.5standardisation on the mathod: The selected approach wil be standardized by conducting a recovery study together with the mixed standard by spiking in the fruits and vegetables. 4.2Monitoring of pesticide residues: four.two.1Sampling programme: Typa of sample: fruits (Mango and Banana) and vegetables (Tomato, Chilli, Caulioflower, Cabbage). Sampling place: From two reputed wholesale markets like.. of West Bengal. Frequency and duration of sampling: As soon as in each and every month for 1 year. Volume of sample: 1 kg of every single sample. 4.two.2pesticide residues to become monitored: All of the pesticides listed in table 2. four.3Decontamination studies The pesticides are to become selected around the basis of their greater use pattern in W.B. the sa]elected pesticides are listed as follows: OC (?-endosulfan, ?-endosulfan endosulfan sulfate, dicofol OP: Chlorpyriphos, Quinalphos, Dimethoate, Triazophos, Malathion, Methyl parathion, phosphamidon, monocrotophos, metasystix; Synthetic pyrethroids: Cypermethrin, Deltamethrin and Fenvalerate. four.three.1Decontamination processes to become followed: 4.three.1.1Washing with water: Chopped samples will probably be taken within a tray containing water and the material will probably be gently rubbed with water for about a single minute as well as the water will probably be decanted or it's rinsed beneath running tap water for 130 sec., with gentle rotation by hand . washing is always to be repeated twice or thrice. four.3.1.2Salt water washing: Chopped samples will likely be dipped in a beaker containing 2% or 55 sodium chloride remedy. Following 10-15 minutes the plant samplws will be gently rubbed by hand in salt answer and salt water is going to be decanted. Then the samples will likely be washed in water. four.3.1.three Boiling/Cooking: Unwashed samples wil be chopped and boiled within a beaker till the water is completely evaporated covering the containr with or with out lid. Samples is usually to be allowed to cool. four.three.1.four Mixture from the above techniques like soak in water for 15 min., rinse with water, reduce into pieces and boiled in water 4.three.1.5Wash with soap resolution, rinse with water.
The impact of household preparation or industrial processing to reduce the pesticide residue levels on raw agricultural commodities (RACs) is considerable as they normally decline the residues. These kinds of processung strudies are intended: To provide info around the transfer of residues in the RAC to the processed merchandise, as a way to calculate reduction factor or concentration variables; To enable and more realistic estimate to become created of the dietary intake of pesticide residues; To establish MRLs for residues in processed merchandise where needed, in line with needs of national regulatory authorities or international requirements. Preferably, RAC samples used in processing research must contain field treated quantifiable residues as close as you possibly can towards the MRL, to ensure that measurable residues are obtained, and transfer variables for the numerous processed commodities could be determined. A transfer element provides the ratio from the residue concentration in the processed commodity to that inside the RAC. For instance when the residue concentration is 0.5 mg/kg in olives and 0.two mg/kg in olive oil, the transfer issue is 0.2/0.5=0.four. A factor 1 (= concentration issue) indicates a concentration effect from the processing procedures. Enhancing the residues either by escalating the application rates, shortening the pre-harvest interval (PHI) or spiking the RAC with the active ingredient and its metabolites in vitro isn't, as and rule, desirable. Spiking is only acceptable in the event the RAC residues may be shown to consist only of surface residues. Nonetheless, in some cases, especially exactly where residues in the RAC are close to the analytical limit of determination, field treatment at exaggerated prices or shortened PHIs is advisable to get enough residue levels for the processing studies.
The initial step in household or industrial food processing may be the preparation of food making use of a variety of mechanical processes, including removing damaged or soiled things or components of crops, washing, peeling, trimming or hulling. This usually leads to important declines inside the volume of pesticide residues inside the remaining edible portions (Petersen et al., 1996; Celik et al., 1995; Schattenberg et al., 1996).
WASHING
Household washing procedures are normally carried out with operating or standing water at moderate temperatures. Detergents, chlorine or ozone can be added for the wash water to improve the effectiveness in the washing procedure (Ong et al., 1996). If needed, numerous washing measures can be performed consequently. The effects rely on the physiochemical properties of the pesticides, such as water solubility, hydrolytic price continuous, volatility and octanol-water partition coefficient (Pow), in conjunction using the actual physical place on the residues; washing processes bring about reduction of hydrophilic residues which are located around the surface in the crops. Furthermore, the temperature from the washing water and the sort of washing has an influence on the residue level. As pointed out by Holland et al. (1994), hot washing along with the addition of detergents are a lot more powerful than cold water washing. Washing coupled with gentle rubbing by hand beneath tap water for 1 min dislodges pesticide residues substantially (Barooah and Yein, 1996). Systemic and lipophilic pesticide residues usually are not removed considerably by washing. Table (1) shows examples of the effects of washing on the residue levels of various pesticides applied to fruits and vegetables.
PEELING
The outer leaves of vegetables usually include residues of pesticides applied for the duration of the expanding season. Consequently, peeling or trimming procedures minimize the residues levels in leafy vegetables. Peeling of root, tuber and bulb vegetables with a knife is typical household practice. Several examples show that the majority of the residues concentration is situated in or around the peel. Peeling in the RACs may possibly eliminate greater than 50% of the pesticide residues present within the commodity. Thus, removal in the peel achieves virtually comprehensive removal of residues, so leaving tiny within the edible portions. This really is specifically important for fruits that are not eaten with their peels, like bananas or citrus fruits. Reynolds (1996) showed that peeling or trimming of carrot decreased the residues of chlorfenvinphos, primiphos-methyl, quinalphos, triazophos resulting a transfer factor of 0.two. Nonetheless, the peel from commercial peeling processes can be utilized as animal feed or for the production of essential oils (citrus) or pectin (citrus, apple etc.). For such industrial processes, it is essential to comprehend that specially non-systemic surface residues are usually concentrated in the peel. For systemic pesticides, peeling may possibly not be as efficient as shown by Sheikhorgan et al (1994). Following application of thiometon on cucumbers, no reduction of residue levels might be detected within the peeled cucumbers. Beneath the Codex Alimentarius, as in other international requirements, MRLs refer for the entire fruits, which can be suitable for assessing compliance with GAP. These MRLs are of restricted significance, even so, in assessing dietary exposure to pesticides from fresh fruits, that are peeled (Holland et al.,1994).
COOKING Cooking procedures at distinct temperatures, the duration in the process, the volume of water or meals additives, as well as the sort of system (open or closed) might have an effect on the residue level. Normally, residues are lowered for the duration of the cooking approach by volatilization in open systems or by hydrolysis in closed systems. In any case, adding cooking liquid dilutes the residues. Many studies have been reported around the dissipation of pesticides in crops during cooking. Moreover for the research summarized in table 1 the behavior in the organophosphorus pesticides chlorfenvinphos, fenitrpothion, isoxathion, methidathion and prothiophos throughout cooking was examined by Nagayama (1996) with green tea leaves, spinach and fruits. These pesticides decreased during the cooking approach corresponding for the boiling time. In accordance with their water solubility, some pesticides have been translocated from the raw materials into the cooking water. However, the pesticide remained in the processed meals based on their octanol-water partition coefficient, which is an indicator of hydrophilic or lipophilic properties on the compound. In exceptional cases, cooking processes could trigger pesticide degradation, yielding a reaction product of toxicological significance. For e.g., daminozide is degraded to UDMH (1, 1-dimethylhydrazine), that is significantly much more potent than the parent compound (Leparulo-Lofus et al.,1992). An additional example is the formation of ETU (Ethylenethiourea) from EBDCs (Ethylene bisdithiocarbamate) fungicides like mancozeb, during heating processes (Petersen et al., 1996).
Dipping in chemical solution Sodium chloride solution is largely used to decontaminate the pesticide residues from different fruits and vegetables .there are several research to prove the efficacy of salt water washing to dislodge the pesticides from crops. Within this procedure, sample of chopped fruits and vegetables is put in a beaker containing 5% sodium chloride solution. After 15 minutes the plant samples are gently rubbed by hand in salt solution and alt water is decanted. The examples in the impact of salt answer therapy on the residue levels of different pesticides applied to vegetables have already been shown in table 1. Kumar et al (2000) reported that dipping of green chillies in 2% salt remedy for ten minute followed by water wash prove to become effective, facilitating the removal of 32.56 and 84.21% residues correspondingly at 0 and 5 days after spray of triazophos (700g a.i./ha) although the acephate residues have been removed to an extent of 78.95% at zero day. Following exact same approach Kumar et al (2000) observed the 90.56 and66.93% reduction correspondingly on 0 and five days soon after spraying of cypermethrin in chillies. Dip remedy of fruits in NaCl resolution, HCl, acetic acid, NaOH solution, potassium permanganate removed 50-60% of surface residues of synthetic pyrethroids in comparison to 40-50% removal by hydrolytic degradation with NaOH (Awasthi, 1986b). Water answer of NaOH, acetic acid potassium dichromate and soap solution used as decontaminating agents for tom . The therapy of fruits with 2% tamarind resolution dip for five minute followed by tap water wash and steam cooking for ten min. was discovered to get rid of the residues of monocrotophos, carbaryl and fenvalerate to an extent of 41.81, 100 and 100% respectively. Treatment with 2% salt answer was equally powerful. Dip therapies in the brinjal fruit wioth water, sodium chloride, HCl solution, acetic acid resolution or potassium permanganate remedy were all located to eliminate 30-33% in the residues of fenvalerate, permethrin, cypermethrin and deltamethrin; NaOH remedy 40-45% and Teepol (a detergent) remedy 50-60%. The effect of washing in lowering the residues decreased progressively in the second and third harvests. A lot of experiments had been carried out with all the 3 frequent household preparations viz. washing with water, salt water washing and cooking to asses their relative efficiencies in reducing the pesticide residues in distinct vegetables. The outcomes have already been summarized in the following table.
Table: Effect of washing, salt water washing and cooking on pesticide residue levels.
Crop Pesticide % of Residue dislodged *ResultReference Washing with waterSalt water washing Cooking CauliflowerMethamidophos41-4846-4746.94 -53.54Largest reduction was brought about by cooking. Jacob and Verma (1990)
Okra Methamidophos 64-72 19-58 58-64Washing with water could remove maximum residues indicating its maximum solubility in water although each of the processes reduced down the TMRL values.Jacob and Verma (1990)
CauliflowerAlpha-cypermethrin 7-38_ 12-17Washing was discovered to become more efficient than cooking possibly due to the thermal stability of cypermethrin.Malik et al (1997)
Cabbage
Chlorpyriphos
Quinalphos
38
41
52.13
56.50
54.three
55With the three processes residues were lowered to some extent. They can not lessen the residue below the MRL. Thus a waiting period of a minimum of 1 and two weeks, respectively, was suggested irrespective of washing cooking for quinalphos and chlorpyriphos on cabbage. Nagesh and Verma (1997)
Cow pea Metasystox
Carbalyl 84.3
87.five 86.four
88.7 83.four
80.8Only boiling from the pod samples could decontaminate the residues present of surface or inside the tissue towards the extent of secure limits by 10th day of treatment.Dikshit et al (1984)
Cauliflower Malathion 60 70 80Cooking was found to be most successful and lowered the TMRL value from one week to zero days.Jacob and Verma (1989)
Bhindi Quinalphos 61.84-64.35 43-53 78-82 Both washing with water and salt water washing brought down the residues under the MRL at zero days, cooking also did this resulting maximum reduction of residues. Jacob and Verma (1985)
Cabbage Malathion
Carbaryl
Pyrethroids 64.60
75.40
22.06 (av.) -
-
-
83.97
89.62
56.72 (av.) The extent of decontamination was larger on account of cooking when compared with washing for all insecticides. Bhatia and Verma (1994) Leaves and curds of cauliflower heads of cabbage and pods of Indian colza
Green beans
Methamidophos
DDT
Malathion
Carbaryl
65.71-77.67
71
96
52
-
-
-
-
80-88.88
52(cooked) 66 (stress cooked)
99(cooked) 99(p.cooked)
77cooked 69(p.cooked)
Cooking dislodges maximum residues.
Water wash removed maximum DDT residues whereas cooking is effective to take away malathion and carbaryl residues.
Dikshit et al (1986)
Elkins et al (1968)
From the above table it can be stated that cooking is most powerful to decrease the residues of different pesticides from different vegetables although in some circumstances washing with water was located to become efficient to reduce the initial residues of pesticides and it has been discovered that with all the ageing of residues or with the improve within the sampling days more than therapies the impact of washing decreases to get rid of the toxicant to the same extent as that of samples collected quickly right after spray where boiling or cooking is identified to be powerful. One of the attainable purpose for high percentage of removal of toxicant from quickly collected samples as the majority of the residues are present on the surface from the samples and hence it's very simple to get rid of by simple washing as observed by Dikshit et al (1984,86) Elkins et al (1968), Bhatia and Verma (1994) and Malik et al (1998). Together with the time elapsed the residues are migrated inside the deeper tissues or strongly adhere on the rough surface of some vegetables. Additionally, the washing can not lessen the residues to the protected level as in comparison with boiling. You can find some studies exactly where each of the three culinary processes proved to be inefficient to minimize the residues beneath the MRL value. Based on Jacob and Verma (1991) residues of quinalphos in the treated cauliflower crop could be lowered only to some extent by various residence processing strategies like washing and cooking. Nagesh and Verma (1997) opined that the inefficiency of the house processes for decontaminating the treated cabbage may be as a result of powerful adsorption properties of quinalphos and chlorpyriphos.
Impact of household preparation for decontamination of pesticide multiresidues in fruits and vegetables Low levels of pesticide residues had been detected in 97(40%) of mt 243 samples analyzed right after following normal household washing, peeling and cooking procedures. The number of samples containing detectable residues dropped to 47(19%) soon after household preparation. These final results indicate that residue level in most commodities are substantially reduced soon after household preparation (Schattenberg et al., 1996) Ramesh and Balasubramanian (1999) performed a study with fruits and vegetables collected from Chennai nearby markets and fortified with known concentrations of numerous pesticides followed by decontamination study with various household preparations like washing, cooking , peeling resulting 65-95% decontamination of pesticide residues at different stages of 512 raw industry samples analyzed, the organochlorine and organophosphorus pesticides present in the 12 samples have been removed resulting in residues effectively below the toxicologically acceptable limits. A brief rinse in tap water reduces pesticide residues on several sorts of make (Krol et al., 2000). Rinsing removed residues for nine on the twelve pesticides studied. Among captan, chlorothalonil, iprodione, vinclozolin, endosulfan, permethrin, methoxichlor, malathion, diazinon, chlorpyriphos, bifenthrin and DDE; residues of vinclozolin, bifenthrin and chlorpyriphos weren't removed. This study confirms that the water solubility of pesticides will not play a substantial role in the observed decrease. The majority of pesticide residues appear to reside around the surface of generate exactly where it really is removed by the mechanical action of rinsing. Earlier research on the effects of industrial and property preparation on pesticide residue in fruits and vegetables have been summarized by Zabik (1987). The early research showed residue reduction to be substantial, with percentage reduction of chlorinated hydrocarbons ranking from 50 to 99+ % for commercial preparation and from 14 to 99+ % for home preparation with all the exception of parathion in spinach and broccoli, commercvial and property prewparation substantially lowered organophosphate residues, using the reduction usually being within the higher 80 or 90% range. Carbamate residues were reduced by 58 to 99+ % when the vegetables have been commercially processed but only by 11 to 92% in home preparation. A recent study in Korea supports these earlier studies (Lee and Lee, 1997). These authors discovered that 45% in the organophosphate residues had been eliminated when the foods were washed in water, 56% with detergent washing, 91% with peeling, and 51% with blanching or boiling.
Methods of multiresidue analysis of pesticides in fruits and vegetables Analysis by gas chromatography
Nakamura et al (1994) developed a approach for multiresidue evaluation of 48 pesticides (20 organophosphorus, 7 organochlorine, 14 organonitrogen and 7 pyrethroid pesticides ) permitted in Japan on the basis of capillary GC after extracting the pesticides with nacetone from vegetable and fruit samples or with acetonitrile from lipid containing crops followed by reextraction into ethyl acetate (test remedy). Organophosphorus pesticides have been directly determined by GC-FPD. Organonitrogen pesticides had been determined by GC-FTD (GC-NPD) following clean up by silica gel chromatography. Organochlorine and pyrethroid pesticides were measured by GC-ECD soon after clean up by florisil column chromatography. Recoveries for ten crops at fortification levels of 0.05-0.25 ppm were 42.5-128.5%. the detection limits were 0.001 ppm for organophosphorus and organochlorine pesticides and 0.01 ppm for organonitrogen and pyrethroid pesticides.
A multiresidue strategy was employed by Dejonckheere et al (1996) for determination of organochlorine, organophosphorus and organonitrogen pesticides in vegetables and fruits which have been extracted with acetone followed by liquid-liquid partitioning with water:apolar pesticides in petroleum ether phase, polar pesticides extracted from aqueous layer with dichloromethane and analyzed by gas chromatography with electron capture (GC-ECD), flame photometric (GC-FPD) and thermoionic certain (GC-TSD) detection.
The method used for multiresidue determination of 52 pesticides such as organophosphorus, organochlorine, organonitrogen, certain pyrethroids and dithiocarbamate pesticides in vegetables and fruits was described by Dogheim et al (1999) using gas chromatography. Samples had been extracted with acetone followed by partitioning with hexane and dichloromethane and estimated by GC-ECD and GC-NPD. Dithiocarbamates were digested in mixture of concentrated HCl, SnCl2 and water for evolution of CS2 which can be collected in an ethanolic answer of copper acetate and diethanolamine to type a yellow complex. The absorbance of yellow product was determined spectrophotometrically at 435 nm. The average recoveries and CVs from the 52 pesticides have been 72-118 and 1-20%, respectively at the spiking levels of 0.01-1 ppm. A similar type of strategy was also described by Kole et al (1998).
Krol et al (2000) used a multiresidue process for determination of 12 pesticides in vegetables exactly where samples have been extracted with two propanol and petroleum ether followed by washing with distilled water 3 times. Final analysis in the samples was performed by GC-ECD, FPD, XSD and/or ELCD.
Ramesah and Balasubramanian (1999) described a strategy to figure out organochlorine, organonitrogen and organophosphorus pesticides in vegetables and fruits following extraction with 2-propanol and petroleum ether by mechanical shaker followed by partitioning with distilled water and column cleanup over florisil for OC and OP pesticides. For organonitrogen pesticides the extraction was accomplished with acetone followed by partitioning with 10%NaCl and ethyl acetate and column clean up more than silica gel. organochlorine, organophosphorus and organonitrogen compounds were analyzed by GC-ECD,GC-FPD and GC-NPD, respectively.
Using GC-ECD, the efficiencies of acetonitrile and acetone to extract the 8 pyrethroids from six fruits and vegetable samples were compared by Pang et al (1997). The extraction efficiency of acetone was competitive with that of acetonitrile for the six fruit and vegetable samples. The ruggedness tests demonstrated further that the proposed approach is straightforward, accurate with excellent precision and suitable for multiresidue analysis of pyrethroid in different agricultural items.
Organophosphorus and organochlorine pesticide residues from fruit and vegetables by capillary GC with electron capture detector (ECD), nitrogen phosphorus detector (NPD), flame photometric detector (FPD) within the sulfur and phosphorus modes, and mass spectrometry detector (MSD) in chosen ion monitoring (SIM) mode had been determined by Torres et al (1995) following extraction by Matrix Strong Phase Dispersion (MSPD) resulting recoveries of 41-108% with relative SD of 2-14% inside the conc. variety 0.5-10 g/liter in oranges, lemons, grapefruit, pears, plums, lettuces and tomatoes. A multiresidue method as described by Sannino et al (1995) for quantitative determination of 39 organophosphorus compounds (parent pesticides and their major metabolites) in 7 fatty processed foods based on automated gel permeation chromatography with a Biobeads SX3 column along with a methylene chloride-cyclohexane (15 + 85) eluant after extraction with methylene chloride. Organophosphorus compounds are quantitated by GC-FPD employing OV-1701 and DB-5 columns. Average recoveries from samples fortified at 0.025-1 mg/kg ranged from 50.6% for dichlorvos to 185% for malaoxon. Determination limits have been among 0.005 and 0.040 mug/mL. Benefits were confirmed by gas chromatography/mass spectrometry with selected-ion monitoring. Gas chromatographic circumstances for separation and identification of the compounds have been chosen employing two capillary columns of different polarities and two detectors, ECD and NPD for multiresidue quantitative determination of 37 pesticides in fruit and vegetables and to study the efficiency of gel-permeation chromatography clean-up soon after ethyl acetate extraction (Balinova,1999). Trova et al (1999) performed liquid chromatographic determination of pesticide residues (such as azinphos-ethyl, azinphos-methyl, carbaryl, diflubenzuron, dinocap and teflubenzuron) in vegetables right after extraction employing an ethyl acetate/n-hexane solvent program instead on the broadly employed methylene chloride. Recoveries as essential by 'Guidelines for residues monitoring within the European Union' have been observed; the new solvent method may be deemed as an alternative to halogenated compounds, dangerous for their toxicity and damaging for their environmental behaviors, in extraction of HPLC-determinable active compounds. A wide range screening technique was proposed by Gelsomino et al (1997) for multiresidue analysis of 77 pesticides (12 organohalogens, 45 organonitrogens, 11 organophosphorus and 9 pyrethroids) in agricultural products making use of gas chromatography equipped with extended, narrow-bore fused-silica open-tubular columns and electron-capture detector (ECD). Residues had been extracted with acetone followed by dichloromethane partitioning and gel permeation chromatographic clean up. Recoveries in the majority of pesticides from spiked samples of carrot, melon and tomato at fortification levels of 0.04-0.10 mg/kg had been 70-108%. Limits of detection have been significantly less than 0.01 mg/kg for ECD. Beena et al (2002, 2003) carried out monitoring of vegetable samples adopting a multiresidue analytical technique employing GC-ECD and GC-NPD systems with capillary columns. Ueno et al (2003) studied an efficient and dependable multiresidue technique for figuring out 52 nitrogen- and/or phosphorus- containing pesticide residues within a large quantity of vegetable samples in which samples have been extracted with acetonitrile, as well as the separated acetonitrile layer was purified by gel permeation chromatography that divided the pesticide eluate into 2 fractoions, the pesticide fractions have been respectively purified by a 2-step minicolumn cleanup, the second fraction via silica gel minicolumn; 1st fraction by way of the tandem minicolumn (florisil minicolumn, inserted on silica gel minicolumn) which was eluted with acetone-petroleum ether (3+7). The combined eluate was subjected to dual column gas chromatography with nitrogen-phosphorus and flame photometric detection. Recoveries of 52 pesticides from fortified samples ranged from 72 to 108% with relative regular deviations of 2-17%, except for the recoveries of methamidophos and chorothalonil. The detection limits from the pesticides had been satisfactory (0.001-0.009 mg/kg) for monitoring of pesticide residues in vegetables. Menkissoglu et al (2004) performed a study from the matrix induced impact for 16 widespread pesticides, most often identified in monitoring studies in tomato pepper and cucumber, utilizing a easy multiresidue method with GC-ECD or NPD, with out a previous cleanup step. Anomalously high GC responses and subsequently quite higher recoveries for a number of pesticides in the extracts have been obtained by a traditional calibration with pesticide resolution in ethyl acetate. A quicker, significantly less effective, environmentally safer supercritical fluid extraction (SFE) approach was evaluated by Garcia et al (1996) over conventional sonvent extraction methods for the extraction of imidacloprid, methiocarb, chlorpyrifos, chlorothalonil, endosulfan-1, endosulfan-2 and endosulfan sulfate, from pepper and tomato employing vegetable sample: anhydrous magnesium sulfate (5:7) mixtures to carryout the extraction with supercritical CO2 and HPLC/DAD,GC/ECD and GC/FPD for evaluation. The selected SFE situations had been 300 atm, 500C, 200l of methanol static modifier, 1 minute static time, and dynamic extraction with 15 ml of CO2 and collection in three ml of ethyl acetate. Except for imidacloprid, which was not recovered beneath any from the assessed circumstances, pesticide recoveries had been higher than 80%. A simplified approach is described by Chaput (1987) where reverse phase liquid chromatography was utilized with post column derivatisation and fluorescence detector to determine 7 N-methyl carbamates (aldicarb, carbaryl, carbofuran, methiocarb, methomyl, oxamyl and propoxur) and three connected metabolites in fruits and vegetables after extraction of the sample with methanol followed by gel permeation chromatography (GPC) or GPC with on-line Nuclear-celite clean up for crops with high chlorophyll and/or carotene content (e.g. cabbage and broccoli). Recovery information have been obtained by fortifying 5 diverse crops (apples, broccoli, cabbage, cauliflower and potatoes) at 0.05 and 0.five ppm. Recoveries averaged 93% at both fortification levels. The coefficient of variation of the method at both levels is
Estimation by GC-MS/LC-MS Because the mass spectrometer is capable of reaching higher levels of molecular specificity as when compared with the classic GC detectors and may be programmed to look for several hundred target ions, GC/MS will be a promising strategy for regulatory agencies to discover for monitoring pesticide residues in daily food provide (Cheng et al, 1994). Cheng et al (1994) reported a multiresidue strategy utilizing gas chromatography /mass spectrometry/selected ion monitoring (GC/MS/SIM) for the determination of captan, chlorothalonil, dichlorovos, dimethoate, EPN, phorate, primiphos-methyl and prothiophos residues in fruits and vegetables. Recoveries have been among 46 and 108% at the 0.five mg/kg fortification degree of each and every pesticide in apples, cabbages, cucumbers and grapes. Coefficients of variation have been between 0.7 and 19%, with an typical of 7.5%. The estimated limits of detection from the pesticides in the crops have been 0.1-0.05 mg/kg, except that captan had limit of detection within the crops higher than 0.5 mg/kg. A approach according to solid-phase extraction using a carbograph 1 cartridge and reverse phase liquid chromatography /mass spectrometry (LC/MS) with an electrospray (ES) interface was described by Corcia et al (1996) for measuring traces of N-methylcarbamate insecticides in ten different varieties of fruits and vegetables .twelve carbamates added to vegetable supplies have been extracted with methanol making use of a homogenizer followed by filtration , an aliquot from the homogenate equivalent to 5 g in the vegetable material was suitably diluted with water and passed via a 1 Carbograpg 1 extraction cartridge. Carbamates have been eluted by passing via the cartridge 6 ml of a CH2Cl2/CH3OH (80:20 v/vegetables) mixture. Recovery from the analytes was much better than 80%, irrespective of the kind vegetable matrix to which the analytes were added. A approach utilizing completely automated solid-phase extraction (SPE) sample cleanup and on-line liquid chromatographic evaluation with UV and fluorescence detection in tandem for determination of carbendazim and thiabendazole in various crops was reported by Hiemstra et al (1995). A total of 199 pesticides have been determined by Fillion et al (1995) in fruits and vegetables utilizing acetonitrile as extracting solvent and a miniaturized charcoal-celite column cleanup followed by gas chromatography with mass-selective detection in selective-ion monitoring mode. Carbamates have been analyzed by liquid chromatography with post column reaction and fluorescence detection. Recovery data had been obtained by fortifying 3 matrixes (pear, carrots and bananas) at 0.1-0.five ppm. Blasco et al (2004) employed a quantitative matrix solid-phase dispersion and liquid chromatographyatmospheric stress chemical ionization mass spectrometry (LC-APCI-MS) approach for the simultaneous analysis of dithiocarbamates and their degradation products in crops. Typical recoveries varied from 33 to 109%, and relative normal deviation was between four and 21% with limits of quantification ranged from 0.25 to two.five mg/kg. A multiresidue evaluation for the determination in the 101 pesticides, like organophosphorus, organochlorine and nitrogen-containing pesticides, in crops by gas chromatography with mass selective detector was performed by Chun et al (2003). Evaluation was performed inside the selected-ion monitoring mode. Samples had been spiked with pesticides at 0.1-1.0 mg/kg. The recoveries of 90% on the pesticides wee between 70 and 110%; even so, the recoveries of acephate and folpet had been extremely poor, i.e.,
Proposed plan of function Standardisation of multiresidue analytical strategies of pesticides
Analytical standard of chosen pesticides belonging to distinct classes viz. OC (HCH (?,?,? and ? isomer), DDT (OP-DDT, PP-DDT, op-DDD, pp-DDE), Endosulfan (?,? and endosulfan sulfate) and dicofol);OP(Dimethoate, Malathion, Methyl parathion, Chlorpyriphos, Quinalphos, Triazophos, Phosphamidon,Dichlorvos Metasystox and Monocrotophos) and Synthetic Pyrethroids (Cypermethrin, Deltamethrin, Fenvalerate) for monitoring and decontamination studies have already been collected from different sources as follows: Sl No.Name in the pesticidesPurity %Source Organochlorine 1?-HCH99.5EPA 2?-HCH99.5EPA three?-HCH99.5EPA 4?-HCH99.5EPA 5OP-DDT99.7EPA 6PP-DDT99.7EPA 7OP-DDD99.7EPA 8PP-DDE99.7EPA 9?-endosulfan99.0Excel 10?-endosulfan99.0Excel 11endosulfan sulfate99.0Excel 12Dicofol96.0Bayer Organophosphorus 13Dimethoate96.5UPL 14Malathion97.3UPL 15Methyl parathion98.5Bayer 16Chlorpyriphos99.7Denocil crop protection Ltd. 17Quinalphos95.6Sandoz Ltd. 18Phosphamidon93.9Bayer 19Triazophos40.8Aventis Crop Science 20Monocrotophos77.0UPL 21Dichlorvos- 22Metasystox- Synthetit pyrethroids CCSRI Cypermethrin,99.0CCSRI Deltamethrin
Fenvalerate99.0
99.0CCSRI
4.1.1Stock normal resolution: Stock standard answer of different pesticides are to be ready in distilled hexane/acetone and diluted suitably to serve as operating normal and to verify the mindividual chromatographic peaks for their suitability for multiresidue evaluation. 4.1.2Preparation of mixed common solytion: from the individual normal options a mixed normal resolution is usually to be prepared for strategy mdevelopment and decontamination research. 4.1.3Extraction and cleanup In the assessment of literature 3 strategies proposed by Kole et al (1998), Nakamura et al (1994) and Obana et al (2001) happen to be chosen to conduct the extraction and cleanup procedure where each the liquid-liquid along with a solid-phase extraction with a cartridge column will be in comparison with create a quick,easier and cost-effective strategy to screen a wide selection of pesticides. 4.1.4Estimation of pesticide multiresidue A gas chromatograph coupled with an Electron Capture Detectore (ECD) and Nitrogen Phosphorus Detector (NPD) is to be employed for estimation of the pesticide residues. The operating conditions may also be studied as stated within the chosen three methods. four.1.5standardisation on the mathod: The selected approach wil be standardized by conducting a recovery study together with the mixed standard by spiking in the fruits and vegetables. 4.2Monitoring of pesticide residues: four.two.1Sampling programme: Typa of sample: fruits (Mango and Banana) and vegetables (Tomato, Chilli, Caulioflower, Cabbage). Sampling place: From two reputed wholesale markets like.. of West Bengal. Frequency and duration of sampling: As soon as in each and every month for 1 year. Volume of sample: 1 kg of every single sample. 4.two.2pesticide residues to become monitored: All of the pesticides listed in table 2. four.3Decontamination studies The pesticides are to become selected around the basis of their greater use pattern in W.B. the sa]elected pesticides are listed as follows: OC (?-endosulfan, ?-endosulfan endosulfan sulfate, dicofol OP: Chlorpyriphos, Quinalphos, Dimethoate, Triazophos, Malathion, Methyl parathion, phosphamidon, monocrotophos, metasystix; Synthetic pyrethroids: Cypermethrin, Deltamethrin and Fenvalerate. four.three.1Decontamination processes to become followed: 4.three.1.1Washing with water: Chopped samples will probably be taken within a tray containing water and the material will probably be gently rubbed with water for about a single minute as well as the water will probably be decanted or it's rinsed beneath running tap water for 130 sec., with gentle rotation by hand . washing is always to be repeated twice or thrice. four.3.1.2Salt water washing: Chopped samples will likely be dipped in a beaker containing 2% or 55 sodium chloride remedy. Following 10-15 minutes the plant samplws will be gently rubbed by hand in salt answer and salt water is going to be decanted. Then the samples will likely be washed in water. four.3.1.three Boiling/Cooking: Unwashed samples wil be chopped and boiled within a beaker till the water is completely evaporated covering the containr with or with out lid. Samples is usually to be allowed to cool. four.three.1.four Mixture from the above techniques like soak in water for 15 min., rinse with water, reduce into pieces and boiled in water 4.three.1.5Wash with soap resolution, rinse with water.
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