DECONTAMINATION OF PESTICIDE RESIDUES ON FRUITS AND VEGETABLES
The impact of household preparation or commercial processing to lessen the pesticide residue levels on raw agricultural commodities (RACs) is important as they normally decline the residues. These kinds of processung strudies are intended: To provide details on the transfer of residues from the RAC for the processed products, in an effort to calculate reduction issue or concentration aspects; To enable and much more realistic estimate to become produced from the dietary intake of pesticide residues; To establish MRLs for residues in processed products where essential, in line with requirements of national regulatory authorities or international requirements. Preferably, RAC samples utilized in processing studies ought to contain field treated quantifiable residues as close as you can towards the MRL, to ensure that measurable residues are obtained, and transfer variables for the a variety of processed commodities might be determined. A transfer factor offers the ratio from the residue concentration inside the processed commodity to that inside the RAC. As an example when the residue concentration is 0.5 mg/kg in olives and 0.2 mg/kg in olive oil, the transfer element is 0.2/0.5=0.four. A element 1 (= concentration issue) indicates a concentration effect from the processing procedures. Enhancing the residues either by rising the application prices, shortening the pre-harvest interval (PHI) or spiking the RAC together 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. Even so, in some cases, particularly exactly where residues inside the RAC are close to the analytical limit of determination, field treatment at exaggerated rates or shortened PHIs is advisable to acquire enough residue levels for the processing studies.
The first step in household or industrial food processing would be the preparation of food employing various mechanical processes, including removing broken or soiled products or components of crops, washing, peeling, trimming or hulling. This frequently leads to substantial declines within the level of pesticide residues within 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 running or standing water at moderate temperatures. Detergents, chlorine or ozone may be added to the wash water to improve the effectiveness from the washing process (Ong et al., 1996). If necessary, many washing measures might be conducted consequently. The effects rely on the physiochemical properties of the pesticides, for example water solubility, hydrolytic rate constant, volatility and octanol-water partition coefficient (Pow), in conjunction with the actual physical place in the residues; washing processes lead to reduction of hydrophilic residues that are located around the surface of the crops. In addition, the temperature from the washing water as well as the type of washing has an influence on the residue level. As pointed out by Holland et al. (1994), hot washing as well as the addition of detergents are more powerful than cold water washing. Washing coupled with gentle rubbing by hand beneath tap water for 1 min dislodges pesticide residues drastically (Barooah and Yein, 1996). Systemic and lipophilic pesticide residues aren't removed drastically by washing. Table (1) shows examples of the effects of washing around the residue levels of distinct pesticides applied to fruits and vegetables.
PEELING
The outer leaves of vegetables often contain residues of pesticides applied during the expanding season. For that reason, peeling or trimming procedures lessen the residues levels in leafy vegetables. Peeling of root, tuber and bulb vegetables using a knife is frequent household practice. Numerous examples show that most of the residues concentration is situated in or on the peel. Peeling from the RACs may possibly eliminate greater than 50% on the pesticide residues present within the commodity. Thus, removal of the peel achieves nearly total removal of residues, so leaving little inside the edible portions. This can be specifically essential for fruits which are not eaten with their peels, including bananas or citrus fruits. Reynolds (1996) showed that peeling or trimming of carrot reduced the residues of chlorfenvinphos, primiphos-methyl, quinalphos, triazophos resulting a transfer aspect of 0.two. Nevertheless, the peel from commercial peeling processes may be used as animal feed or for the production of essential oils (citrus) or pectin (citrus, apple and so on.). For such industrial processes, it truly is critical to understand that particularly non-systemic surface residues are typically concentrated inside the peel. For systemic pesticides, peeling might not be as powerful 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. Below the Codex Alimentarius, as in other international requirements, MRLs refer towards the whole fruits, that is suitable for assessing compliance with GAP. These MRLs are of restricted significance, nonetheless, in assessing dietary exposure to pesticides from fresh fruits, which are peeled (Holland et al.,1994).
COOKING Cooking procedures at diverse temperatures, the duration from the approach, the volume of water or meals additives, as well as the sort of method (open or closed) may have an impact around the residue level. Usually, residues are reduced during the cooking method by volatilization in open systems or by hydrolysis in closed systems. In any case, adding cooking liquid dilutes the residues. Several studies have been reported on the dissipation of pesticides in crops for the duration of cooking. In addition towards the research summarized in table 1 the behavior in the organophosphorus pesticides chlorfenvinphos, fenitrpothion, isoxathion, methidathion and prothiophos in the course of cooking was examined by Nagayama (1996) with green tea leaves, spinach and fruits. These pesticides decreased for the duration of the cooking method corresponding to the boiling time. According to their water solubility, some pesticides were translocated from the raw materials into the cooking water. However, the pesticide remained within the processed food based on their octanol-water partition coefficient, which is an indicator of hydrophilic or lipophilic properties from the compound. In exceptional circumstances, cooking processes could lead to pesticide degradation, yielding a reaction product of toxicological significance. For e.g., daminozide is degraded to UDMH (1, 1-dimethylhydrazine), which can be much far more potent than the parent compound (Leparulo-Lofus et al.,1992). One more instance is the formation of ETU (Ethylenethiourea) from EBDCs (Ethylene bisdithiocarbamate) fungicides like mancozeb, during heating processes (Petersen et al., 1996).
Dipping in chemical resolution Sodium chloride solution is largely utilised to decontaminate the pesticide residues from distinct fruits and vegetables .there are lots of research to prove the efficacy of salt water washing to dislodge the pesticides from crops. Within this approach, sample of chopped fruits and vegetables is place inside a beaker containing 5% sodium chloride solution. Right 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 resolution remedy on the residue levels of different pesticides applied to vegetables have been shown in table 1. Kumar et al (2000) reported that dipping of green chillies in 2% salt remedy for 10 minute followed by water wash prove to be efficient, facilitating the removal of 32.56 and 84.21% residues correspondingly at 0 and five days after spray of triazophos (700g a.i./ha) while the acephate residues had been removed to an extent of 78.95% at zero day. Following same technique Kumar et al (2000) observed the 90.56 and66.93% reduction correspondingly on 0 and five days following spraying of cypermethrin in chillies. Dip treatment of fruits in NaCl remedy, HCl, acetic acid, NaOH remedy, potassium permanganate removed 50-60% of surface residues of synthetic pyrethroids when compared with 40-50% removal by hydrolytic degradation with NaOH (Awasthi, 1986b). Water resolution of NaOH, acetic acid potassium dichromate and soap solution employed as decontaminating agents for tom . The remedy of fruits with 2% tamarind resolution dip for 5 minute followed by tap water wash and steam cooking for 10 min. was located to eliminate the residues of monocrotophos, carbaryl and fenvalerate to an extent of 41.81, 100 and 100% respectively. Remedy with 2% salt solution was equally efficient. Dip therapies on the brinjal fruit wioth water, sodium chloride, HCl answer, acetic acid remedy or potassium permanganate resolution have been all identified to remove 30-33% in the residues of fenvalerate, permethrin, cypermethrin and deltamethrin; NaOH solution 40-45% and Teepol (a detergent) solution 50-60%. The effect of washing in reducing the residues decreased progressively in the second and third harvests. A lot of experiments were carried out using the 3 common household preparations viz. washing with water, salt water washing and cooking to asses their relative efficiencies in reducing the pesticide residues in diverse vegetables. The results have already been summarized within 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 eliminate maximum residues indicating its maximum solubility in water even though all of the processes decrease down the TMRL values.Jacob and Verma (1990)
CauliflowerAlpha-cypermethrin 7-38_ 12-17Washing was discovered to become a lot more effective than cooking almost certainly as a result of 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 minimize the residue beneath the MRL. Thus a waiting period of a minimum of one 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
87.5 86.four
88.7 83.four
80.8Only boiling of the pod samples could decontaminate the residues present of surface or inside the tissue to the extent of safe limits by 10th day of remedy.Dikshit et al (1984)
Cauliflower Malathion 60 70 80Cooking was found to become most efficient and lowered the TMRL worth from one week to zero days.Jacob and Verma (1989)
Bhindi Quinalphos 61.84-64.35 43-53 78-82 Each washing with water and salt water washing brought down the residues below 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 greater as a result of cooking in comparison to 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 powerful to get rid of malathion and carbaryl residues.
Dikshit et al (1986)
Elkins et al (1968)
From the above table it could be mentioned that cooking is most successful to reduce the residues of diverse pesticides from numerous vegetables though in some circumstances washing with water was identified to become successful to minimize the initial residues of pesticides and it has been discovered that together with the ageing of residues or with all the improve inside the sampling days over treatments the effect of washing decreases to remove the toxicant to the exact same extent as that of samples collected immediately right after spray exactly where boiling or cooking is discovered to be efficient. Among the possible cause for high percentage of removal of toxicant from quickly collected samples as most of the residues are present of the surface in the samples and therefore it really is extremely easy to take away by basic 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 around the rough surface of some vegetables. In addition, the washing can not lessen the residues towards the protected level as compared to boiling. You will find some research exactly where all of the 3 culinary processes proved to be inefficient to reduce the residues below the MRL worth. According to Jacob and Verma (1991) residues of quinalphos inside the treated cauliflower crop will be reduced only to some extent by various home processing approaches like washing and cooking. Nagesh and Verma (1997) opined that the inefficiency from the property processes for decontaminating the treated cabbage may be due to the sturdy adsorption properties of quinalphos and chlorpyriphos.
Effect of household preparation for decontamination of pesticide multiresidues in fruits and vegetables Low levels of pesticide residues have been detected in 97(40%) of mt 243 samples analyzed following following regular household washing, peeling and cooking procedures. The number of samples containing detectable residues dropped to 47(19%) soon after household preparation. These outcomes indicate that residue level in most commodities are substantially reduced following household preparation (Schattenberg et al., 1996) Ramesh and Balasubramanian (1999) performed a study with fruits and vegetables collected from Chennai regional 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 various stages of 512 raw market place samples analyzed, the organochlorine and organophosphorus pesticides present within the 12 samples have been removed resulting in residues nicely under the toxicologically acceptable limits. A quick rinse in tap water reduces pesticide residues on many sorts of make (Krol et al., 2000). Rinsing removed residues for nine in the twelve pesticides studied. Among captan, chlorothalonil, iprodione, vinclozolin, endosulfan, permethrin, methoxichlor, malathion, diazinon, chlorpyriphos, bifenthrin and DDE; residues of vinclozolin, bifenthrin and chlorpyriphos were not removed. This study confirms that the water solubility of pesticides will not play a significant function within the observed reduce. The majority of pesticide residues appear to reside around the surface of produce exactly where it is removed by the mechanical action of rinsing. Earlier studies in the effects of industrial and property preparation on pesticide residue in fruits and vegetables were summarized by Zabik (1987). The early studies showed residue reduction to be substantial, with percentage reduction of chlorinated hydrocarbons ranking from 50 to 99+ % for industrial preparation and from 14 to 99+ % for property preparation using the exception of parathion in spinach and broccoli, commercvial and residence prewparation substantially lowered organophosphate residues, together with the reduction normally getting within the high 80 or 90% range. Carbamate residues had been lowered by 58 to 99+ % when the vegetables were commercially processed but only by 11 to 92% in property preparation. A recent study in Korea supports these earlier studies (Lee and Lee, 1997). These authors identified that 45% from the organophosphate residues were eliminated when the foods were washed in water, 56% with detergent washing, 91% with peeling, and 51% with blanching or boiling.
Techniques of multiresidue evaluation of pesticides in fruits and vegetables Evaluation by gas chromatography
Nakamura et al (1994) developed a technique 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 soon 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 solution). Organophosphorus pesticides had been directly determined by GC-FPD. Organonitrogen pesticides were determined by GC-FTD (GC-NPD) following clean up by silica gel chromatography. Organochlorine and pyrethroid pesticides have been measured by GC-ECD following 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 had been 0.001 ppm for organophosphorus and organochlorine pesticides and 0.01 ppm for organonitrogen and pyrethroid pesticides.
A multiresidue approach was used by Dejonckheere et al (1996) for determination of organochlorine, organophosphorus and organonitrogen pesticides in vegetables and fruits which had 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 technique utilised for multiresidue determination of 52 pesticides such as organophosphorus, organochlorine, organonitrogen, specific pyrethroids and dithiocarbamate pesticides in vegetables and fruits was described by Dogheim et al (1999) utilizing gas chromatography. Samples were extracted with acetone followed by partitioning with hexane and dichloromethane and estimated by GC-ECD and GC-NPD. Dithiocarbamates had been digested in mixture of concentrated HCl, SnCl2 and water for evolution of CS2 which is collected in an ethanolic solution of copper acetate and diethanolamine to kind a yellow complex. The absorbance of yellow product was determined spectrophotometrically at 435 nm. The typical recoveries and CVs of the 52 pesticides had been 72-118 and 1-20%, respectively in 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) utilized a multiresidue procedure for determination of 12 pesticides in vegetables where samples were extracted with 2 propanol and petroleum ether followed by washing with distilled water three occasions. Final analysis in the samples was performed by GC-ECD, FPD, XSD and/or ELCD.
Ramesah and Balasubramanian (1999) described a technique to establish 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 more than florisil for OC and OP pesticides. For organonitrogen pesticides the extraction was carried out 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.
Making use of GC-ECD, the efficiencies of acetonitrile and acetone to extract the 8 pyrethroids from 6 fruits and vegetable samples have been 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 additional that the proposed approach is easy, correct with great precision and suitable for multiresidue evaluation of pyrethroid in numerous 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) in the sulfur and phosphorus modes, and mass spectrometry detector (MSD) in chosen ion monitoring (SIM) mode were determined by Torres et al (1995) following extraction by Matrix Solid 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 strategy 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 according to automated gel permeation chromatography using a Biobeads SX3 column and a methylene chloride-cyclohexane (15 + 85) eluant following extraction with methylene chloride. Organophosphorus compounds are quantitated by GC-FPD making use of 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 in between 0.005 and 0.040 mug/mL. Results had been confirmed by gas chromatography/mass spectrometry with selected-ion monitoring. Gas chromatographic circumstances for separation and identification on the compounds had been chosen utilizing two capillary columns of diverse 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 after extraction utilizing an ethyl acetate/n-hexane solvent system rather of the broadly employed methylene chloride. Recoveries as essential by 'Guidelines for residues monitoring inside the European Union' had been observed; the new solvent method might be regarded as an option to halogenated compounds, dangerous for their toxicity and harmful for their environmental behaviors, in extraction of HPLC-determinable active compounds. A wide variety 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 merchandise employing gas chromatography equipped with lengthy, 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 from the majority of pesticides from spiked samples of carrot, melon and tomato at fortification levels of 0.04-0.10 mg/kg have been 70-108%. Limits of detection were less than 0.01 mg/kg for ECD. Beena et al (2002, 2003) carried out monitoring of vegetable samples adopting a multiresidue analytical method employing GC-ECD and GC-NPD systems with capillary columns. Ueno et al (2003) studied an effective and dependable multiresidue technique for figuring out 52 nitrogen- and/or phosphorus- containing pesticide residues inside a big quantity of vegetable samples in which samples have been extracted with acetonitrile, along with 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 by means of silica gel minicolumn; first fraction via 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 of the pesticides have been satisfactory (0.001-0.009 mg/kg) for monitoring of pesticide residues in vegetables. Menkissoglu et al (2004) performed a study in the matrix induced effect for 16 widespread pesticides, most often identified in monitoring studies in tomato pepper and cucumber, using a basic multiresidue method with GC-ECD or NPD, with out a prior cleanup step. Anomalously high GC responses and subsequently quite high recoveries for many pesticides within the extracts were obtained by a conventional calibration with pesticide answer in ethyl acetate. A more quickly, much less effective, environmentally safer supercritical fluid extraction (SFE) method was evaluated by Garcia et al (1996) more than traditional sonvent extraction techniques 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 (five:7) mixtures to carryout the extraction with supercritical CO2 and HPLC/DAD,GC/ECD and GC/FPD for evaluation. The chosen SFE circumstances have been 300 atm, 500C, 200l of methanol static modifier, 1 minute static time, and dynamic extraction with 15 ml of CO2 and collection in 3 ml of ethyl acetate. Except for imidacloprid, which was not recovered under any on the assessed situations, pesticide recoveries had been greater than 80%. A simplified strategy 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 3 connected metabolites in fruits and vegetables soon after extraction in the sample with methanol followed by gel permeation chromatography (GPC) or GPC with on-line Nuclear-celite clean up for crops with higher chlorophyll and/or carotene content material (e.g. cabbage and broccoli). Recovery information have been obtained by fortifying five different crops (apples, broccoli, cabbage, cauliflower and potatoes) at 0.05 and 0.five ppm. Recoveries averaged 93% at each fortification levels. The coefficient of variation from the method at both levels is
Estimation by GC-MS/LC-MS Since the mass spectrometer is capable of achieving larger levels of molecular specificity as compared to the classic GC detectors and can be programmed to look for a number of hundred target ions, GC/MS could be a promising approach for regulatory agencies to discover for monitoring pesticide residues in daily food supply (Cheng et al, 1994). Cheng et al (1994) reported a multiresidue approach employing 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 were amongst 46 and 108% at the 0.five mg/kg fortification level of each pesticide in apples, cabbages, cucumbers and grapes. Coefficients of variation have been in between 0.7 and 19%, with an average of 7.5%. The estimated limits of detection from the pesticides within the crops have been 0.1-0.05 mg/kg, except that captan had limit of detection in the crops larger than 0.5 mg/kg. A method depending on 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 various sorts of fruits and vegetables .twelve carbamates added to vegetable components have been extracted with methanol using a homogenizer followed by filtration , an aliquot from the homogenate equivalent to 5 g of the vegetable material was suitably diluted with water and passed via a 1 Carbograpg 1 extraction cartridge. Carbamates have been eluted by passing by means of the cartridge six ml of a CH2Cl2/CH3OH (80:20 v/vegetables) mixture. Recovery in the analytes was far better than 80%, irrespective on the variety vegetable matrix to which the analytes had been added. A strategy employing 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 were determined by Fillion et al (1995) in fruits and vegetables utilizing acetonitrile as extracting solvent as well as 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 were obtained by fortifying 3 matrixes (pear, carrots and bananas) at 0.1-0.five ppm. Blasco et al (2004) utilised a quantitative matrix solid-phase dispersion and liquid chromatographyatmospheric pressure chemical ionization mass spectrometry (LC-APCI-MS) method for the simultaneous analysis of dithiocarbamates and their degradation goods in crops. Typical recoveries varied from 33 to 109%, and relative regular deviation was among four and 21% with limits of quantification ranged from 0.25 to two.five mg/kg. A multiresidue analysis for the determination on the 101 pesticides, including organophosphorus, organochlorine and nitrogen-containing pesticides, in crops by gas chromatography with mass selective detector was performed by Chun et al (2003). Analysis was performed in the selected-ion monitoring mode. Samples have been spiked with pesticides at 0.1-1.0 mg/kg. The recoveries of 90% from the pesticides wee among 70 and 110%; however, the recoveries of acephate and folpet were really poor, i.e.,
Proposed strategy of operate Standardisation of multiresidue analytical techniques of pesticides
Analytical standard of chosen pesticides belonging to various 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 research have been collected from various sources as follows: Sl No.Name in the pesticidesPurity %Source Organochlorine 1?-HCH99.5EPA two?-HCH99.5EPA 3?-HCH99.5EPA four?-HCH99.5EPA 5OP-DDT99.7EPA 6PP-DDT99.7EPA 7OP-DDD99.7EPA 8PP-DDE99.7EPA 9?-endosulfan99.0Excel ten?-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 remedy: Stock normal remedy of different pesticides are to be ready in distilled hexane/acetone and diluted suitably to serve as operating standard and to check the mindividual chromatographic peaks for their suitability for multiresidue evaluation. four.1.2Preparation of mixed standard solytion: from the individual common options a mixed normal remedy is to be ready for approach mdevelopment and decontamination research. 4.1.3Extraction and cleanup In the overview of literature 3 techniques proposed by Kole et al (1998), Nakamura et al (1994) and Obana et al (2001) have been selected to conduct the extraction and cleanup process exactly where each the liquid-liquid as well as a solid-phase extraction using a cartridge column will likely be in comparison to develop a rapidly,simpler and cost-effective strategy to screen a wide array of pesticides. 4.1.4Estimation of pesticide multiresidue A gas chromatograph coupled with an Electron Capture Detectore (ECD) and Nitrogen Phosphorus Detector (NPD) would be to be utilised for estimation on the pesticide residues. The operating circumstances will also be studied as stated inside the chosen 3 approaches. 4.1.5standardisation in the mathod: The selected strategy wil be standardized by conducting a recovery study with all the mixed standard by spiking within the fruits and vegetables. 4.2Monitoring of pesticide residues: 4.two.1Sampling programme: Typa of sample: fruits (Mango and Banana) and vegetables (Tomato, Chilli, Caulioflower, Cabbage). Sampling place: From 2 reputed wholesale markets like.. of West Bengal. Frequency and duration of sampling: Once in each month for one particular 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 research The pesticides are to be selected around the basis of their larger 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.3.1Decontamination processes to be followed: four.three.1.1Washing with water: Chopped samples will likely be taken within a tray containing water as well as the material is going to be gently rubbed with water for about one minute and also the water will probably be decanted or it is rinsed beneath operating tap water for 130 sec., with gentle rotation by hand . washing is to be repeated twice or thrice. 4.3.1.2Salt water washing: Chopped samples will likely be dipped within a beaker containing 2% or 55 sodium chloride answer. After 10-15 minutes the plant samplws is going to be gently rubbed by hand in salt solution and salt water will probably be decanted. Then the samples will be washed in water. 4.3.1.3 Boiling/Cooking: Unwashed samples wil be chopped and boiled within a beaker till the water is completely evaporated covering the containr with or with no lid. Samples is usually to be permitted to cool. 4.three.1.4 Mixture in the above approaches like soak in water for 15 min., rinse with water, reduce into pieces and boiled in water 4.3.1.5Wash with soap resolution, rinse with water.
The impact of household preparation or commercial processing to lessen the pesticide residue levels on raw agricultural commodities (RACs) is important as they normally decline the residues. These kinds of processung strudies are intended: To provide details on the transfer of residues from the RAC for the processed products, in an effort to calculate reduction issue or concentration aspects; To enable and much more realistic estimate to become produced from the dietary intake of pesticide residues; To establish MRLs for residues in processed products where essential, in line with requirements of national regulatory authorities or international requirements. Preferably, RAC samples utilized in processing studies ought to contain field treated quantifiable residues as close as you can towards the MRL, to ensure that measurable residues are obtained, and transfer variables for the a variety of processed commodities might be determined. A transfer factor offers the ratio from the residue concentration inside the processed commodity to that inside the RAC. As an example when the residue concentration is 0.5 mg/kg in olives and 0.2 mg/kg in olive oil, the transfer element is 0.2/0.5=0.four. A element 1 (= concentration issue) indicates a concentration effect from the processing procedures. Enhancing the residues either by rising the application prices, shortening the pre-harvest interval (PHI) or spiking the RAC together 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. Even so, in some cases, particularly exactly where residues inside the RAC are close to the analytical limit of determination, field treatment at exaggerated rates or shortened PHIs is advisable to acquire enough residue levels for the processing studies.
The first step in household or industrial food processing would be the preparation of food employing various mechanical processes, including removing broken or soiled products or components of crops, washing, peeling, trimming or hulling. This frequently leads to substantial declines within the level of pesticide residues within 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 running or standing water at moderate temperatures. Detergents, chlorine or ozone may be added to the wash water to improve the effectiveness from the washing process (Ong et al., 1996). If necessary, many washing measures might be conducted consequently. The effects rely on the physiochemical properties of the pesticides, for example water solubility, hydrolytic rate constant, volatility and octanol-water partition coefficient (Pow), in conjunction with the actual physical place in the residues; washing processes lead to reduction of hydrophilic residues that are located around the surface of the crops. In addition, the temperature from the washing water as well as the type of washing has an influence on the residue level. As pointed out by Holland et al. (1994), hot washing as well as the addition of detergents are more powerful than cold water washing. Washing coupled with gentle rubbing by hand beneath tap water for 1 min dislodges pesticide residues drastically (Barooah and Yein, 1996). Systemic and lipophilic pesticide residues aren't removed drastically by washing. Table (1) shows examples of the effects of washing around the residue levels of distinct pesticides applied to fruits and vegetables.
PEELING
The outer leaves of vegetables often contain residues of pesticides applied during the expanding season. For that reason, peeling or trimming procedures lessen the residues levels in leafy vegetables. Peeling of root, tuber and bulb vegetables using a knife is frequent household practice. Numerous examples show that most of the residues concentration is situated in or on the peel. Peeling from the RACs may possibly eliminate greater than 50% on the pesticide residues present within the commodity. Thus, removal of the peel achieves nearly total removal of residues, so leaving little inside the edible portions. This can be specifically essential for fruits which are not eaten with their peels, including bananas or citrus fruits. Reynolds (1996) showed that peeling or trimming of carrot reduced the residues of chlorfenvinphos, primiphos-methyl, quinalphos, triazophos resulting a transfer aspect of 0.two. Nevertheless, the peel from commercial peeling processes may be used as animal feed or for the production of essential oils (citrus) or pectin (citrus, apple and so on.). For such industrial processes, it truly is critical to understand that particularly non-systemic surface residues are typically concentrated inside the peel. For systemic pesticides, peeling might not be as powerful 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. Below the Codex Alimentarius, as in other international requirements, MRLs refer towards the whole fruits, that is suitable for assessing compliance with GAP. These MRLs are of restricted significance, nonetheless, in assessing dietary exposure to pesticides from fresh fruits, which are peeled (Holland et al.,1994).
COOKING Cooking procedures at diverse temperatures, the duration from the approach, the volume of water or meals additives, as well as the sort of method (open or closed) may have an impact around the residue level. Usually, residues are reduced during the cooking method by volatilization in open systems or by hydrolysis in closed systems. In any case, adding cooking liquid dilutes the residues. Several studies have been reported on the dissipation of pesticides in crops for the duration of cooking. In addition towards the research summarized in table 1 the behavior in the organophosphorus pesticides chlorfenvinphos, fenitrpothion, isoxathion, methidathion and prothiophos in the course of cooking was examined by Nagayama (1996) with green tea leaves, spinach and fruits. These pesticides decreased for the duration of the cooking method corresponding to the boiling time. According to their water solubility, some pesticides were translocated from the raw materials into the cooking water. However, the pesticide remained within the processed food based on their octanol-water partition coefficient, which is an indicator of hydrophilic or lipophilic properties from the compound. In exceptional circumstances, cooking processes could lead to pesticide degradation, yielding a reaction product of toxicological significance. For e.g., daminozide is degraded to UDMH (1, 1-dimethylhydrazine), which can be much far more potent than the parent compound (Leparulo-Lofus et al.,1992). One more instance is the formation of ETU (Ethylenethiourea) from EBDCs (Ethylene bisdithiocarbamate) fungicides like mancozeb, during heating processes (Petersen et al., 1996).
Dipping in chemical resolution Sodium chloride solution is largely utilised to decontaminate the pesticide residues from distinct fruits and vegetables .there are lots of research to prove the efficacy of salt water washing to dislodge the pesticides from crops. Within this approach, sample of chopped fruits and vegetables is place inside a beaker containing 5% sodium chloride solution. Right 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 resolution remedy on the residue levels of different pesticides applied to vegetables have been shown in table 1. Kumar et al (2000) reported that dipping of green chillies in 2% salt remedy for 10 minute followed by water wash prove to be efficient, facilitating the removal of 32.56 and 84.21% residues correspondingly at 0 and five days after spray of triazophos (700g a.i./ha) while the acephate residues had been removed to an extent of 78.95% at zero day. Following same technique Kumar et al (2000) observed the 90.56 and66.93% reduction correspondingly on 0 and five days following spraying of cypermethrin in chillies. Dip treatment of fruits in NaCl remedy, HCl, acetic acid, NaOH remedy, potassium permanganate removed 50-60% of surface residues of synthetic pyrethroids when compared with 40-50% removal by hydrolytic degradation with NaOH (Awasthi, 1986b). Water resolution of NaOH, acetic acid potassium dichromate and soap solution employed as decontaminating agents for tom . The remedy of fruits with 2% tamarind resolution dip for 5 minute followed by tap water wash and steam cooking for 10 min. was located to eliminate the residues of monocrotophos, carbaryl and fenvalerate to an extent of 41.81, 100 and 100% respectively. Remedy with 2% salt solution was equally efficient. Dip therapies on the brinjal fruit wioth water, sodium chloride, HCl answer, acetic acid remedy or potassium permanganate resolution have been all identified to remove 30-33% in the residues of fenvalerate, permethrin, cypermethrin and deltamethrin; NaOH solution 40-45% and Teepol (a detergent) solution 50-60%. The effect of washing in reducing the residues decreased progressively in the second and third harvests. A lot of experiments were carried out using the 3 common household preparations viz. washing with water, salt water washing and cooking to asses their relative efficiencies in reducing the pesticide residues in diverse vegetables. The results have already been summarized within 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 eliminate maximum residues indicating its maximum solubility in water even though all of the processes decrease down the TMRL values.Jacob and Verma (1990)
CauliflowerAlpha-cypermethrin 7-38_ 12-17Washing was discovered to become a lot more effective than cooking almost certainly as a result of 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 minimize the residue beneath the MRL. Thus a waiting period of a minimum of one 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
87.5 86.four
88.7 83.four
80.8Only boiling of the pod samples could decontaminate the residues present of surface or inside the tissue to the extent of safe limits by 10th day of remedy.Dikshit et al (1984)
Cauliflower Malathion 60 70 80Cooking was found to become most efficient and lowered the TMRL worth from one week to zero days.Jacob and Verma (1989)
Bhindi Quinalphos 61.84-64.35 43-53 78-82 Each washing with water and salt water washing brought down the residues below 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 greater as a result of cooking in comparison to 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 powerful to get rid of malathion and carbaryl residues.
Dikshit et al (1986)
Elkins et al (1968)
From the above table it could be mentioned that cooking is most successful to reduce the residues of diverse pesticides from numerous vegetables though in some circumstances washing with water was identified to become successful to minimize the initial residues of pesticides and it has been discovered that together with the ageing of residues or with all the improve inside the sampling days over treatments the effect of washing decreases to remove the toxicant to the exact same extent as that of samples collected immediately right after spray exactly where boiling or cooking is discovered to be efficient. Among the possible cause for high percentage of removal of toxicant from quickly collected samples as most of the residues are present of the surface in the samples and therefore it really is extremely easy to take away by basic 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 around the rough surface of some vegetables. In addition, the washing can not lessen the residues towards the protected level as compared to boiling. You will find some research exactly where all of the 3 culinary processes proved to be inefficient to reduce the residues below the MRL worth. According to Jacob and Verma (1991) residues of quinalphos inside the treated cauliflower crop will be reduced only to some extent by various home processing approaches like washing and cooking. Nagesh and Verma (1997) opined that the inefficiency from the property processes for decontaminating the treated cabbage may be due to the sturdy adsorption properties of quinalphos and chlorpyriphos.
Effect of household preparation for decontamination of pesticide multiresidues in fruits and vegetables Low levels of pesticide residues have been detected in 97(40%) of mt 243 samples analyzed following following regular household washing, peeling and cooking procedures. The number of samples containing detectable residues dropped to 47(19%) soon after household preparation. These outcomes indicate that residue level in most commodities are substantially reduced following household preparation (Schattenberg et al., 1996) Ramesh and Balasubramanian (1999) performed a study with fruits and vegetables collected from Chennai regional 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 various stages of 512 raw market place samples analyzed, the organochlorine and organophosphorus pesticides present within the 12 samples have been removed resulting in residues nicely under the toxicologically acceptable limits. A quick rinse in tap water reduces pesticide residues on many sorts of make (Krol et al., 2000). Rinsing removed residues for nine in the twelve pesticides studied. Among captan, chlorothalonil, iprodione, vinclozolin, endosulfan, permethrin, methoxichlor, malathion, diazinon, chlorpyriphos, bifenthrin and DDE; residues of vinclozolin, bifenthrin and chlorpyriphos were not removed. This study confirms that the water solubility of pesticides will not play a significant function within the observed reduce. The majority of pesticide residues appear to reside around the surface of produce exactly where it is removed by the mechanical action of rinsing. Earlier studies in the effects of industrial and property preparation on pesticide residue in fruits and vegetables were summarized by Zabik (1987). The early studies showed residue reduction to be substantial, with percentage reduction of chlorinated hydrocarbons ranking from 50 to 99+ % for industrial preparation and from 14 to 99+ % for property preparation using the exception of parathion in spinach and broccoli, commercvial and residence prewparation substantially lowered organophosphate residues, together with the reduction normally getting within the high 80 or 90% range. Carbamate residues had been lowered by 58 to 99+ % when the vegetables were commercially processed but only by 11 to 92% in property preparation. A recent study in Korea supports these earlier studies (Lee and Lee, 1997). These authors identified that 45% from the organophosphate residues were eliminated when the foods were washed in water, 56% with detergent washing, 91% with peeling, and 51% with blanching or boiling.
Techniques of multiresidue evaluation of pesticides in fruits and vegetables Evaluation by gas chromatography
Nakamura et al (1994) developed a technique 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 soon 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 solution). Organophosphorus pesticides had been directly determined by GC-FPD. Organonitrogen pesticides were determined by GC-FTD (GC-NPD) following clean up by silica gel chromatography. Organochlorine and pyrethroid pesticides have been measured by GC-ECD following 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 had been 0.001 ppm for organophosphorus and organochlorine pesticides and 0.01 ppm for organonitrogen and pyrethroid pesticides.
A multiresidue approach was used by Dejonckheere et al (1996) for determination of organochlorine, organophosphorus and organonitrogen pesticides in vegetables and fruits which had 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 technique utilised for multiresidue determination of 52 pesticides such as organophosphorus, organochlorine, organonitrogen, specific pyrethroids and dithiocarbamate pesticides in vegetables and fruits was described by Dogheim et al (1999) utilizing gas chromatography. Samples were extracted with acetone followed by partitioning with hexane and dichloromethane and estimated by GC-ECD and GC-NPD. Dithiocarbamates had been digested in mixture of concentrated HCl, SnCl2 and water for evolution of CS2 which is collected in an ethanolic solution of copper acetate and diethanolamine to kind a yellow complex. The absorbance of yellow product was determined spectrophotometrically at 435 nm. The typical recoveries and CVs of the 52 pesticides had been 72-118 and 1-20%, respectively in 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) utilized a multiresidue procedure for determination of 12 pesticides in vegetables where samples were extracted with 2 propanol and petroleum ether followed by washing with distilled water three occasions. Final analysis in the samples was performed by GC-ECD, FPD, XSD and/or ELCD.
Ramesah and Balasubramanian (1999) described a technique to establish 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 more than florisil for OC and OP pesticides. For organonitrogen pesticides the extraction was carried out 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.
Making use of GC-ECD, the efficiencies of acetonitrile and acetone to extract the 8 pyrethroids from 6 fruits and vegetable samples have been 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 additional that the proposed approach is easy, correct with great precision and suitable for multiresidue evaluation of pyrethroid in numerous 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) in the sulfur and phosphorus modes, and mass spectrometry detector (MSD) in chosen ion monitoring (SIM) mode were determined by Torres et al (1995) following extraction by Matrix Solid 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 strategy 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 according to automated gel permeation chromatography using a Biobeads SX3 column and a methylene chloride-cyclohexane (15 + 85) eluant following extraction with methylene chloride. Organophosphorus compounds are quantitated by GC-FPD making use of 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 in between 0.005 and 0.040 mug/mL. Results had been confirmed by gas chromatography/mass spectrometry with selected-ion monitoring. Gas chromatographic circumstances for separation and identification on the compounds had been chosen utilizing two capillary columns of diverse 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 after extraction utilizing an ethyl acetate/n-hexane solvent system rather of the broadly employed methylene chloride. Recoveries as essential by 'Guidelines for residues monitoring inside the European Union' had been observed; the new solvent method might be regarded as an option to halogenated compounds, dangerous for their toxicity and harmful for their environmental behaviors, in extraction of HPLC-determinable active compounds. A wide variety 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 merchandise employing gas chromatography equipped with lengthy, 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 from the majority of pesticides from spiked samples of carrot, melon and tomato at fortification levels of 0.04-0.10 mg/kg have been 70-108%. Limits of detection were less than 0.01 mg/kg for ECD. Beena et al (2002, 2003) carried out monitoring of vegetable samples adopting a multiresidue analytical method employing GC-ECD and GC-NPD systems with capillary columns. Ueno et al (2003) studied an effective and dependable multiresidue technique for figuring out 52 nitrogen- and/or phosphorus- containing pesticide residues inside a big quantity of vegetable samples in which samples have been extracted with acetonitrile, along with 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 by means of silica gel minicolumn; first fraction via 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 of the pesticides have been satisfactory (0.001-0.009 mg/kg) for monitoring of pesticide residues in vegetables. Menkissoglu et al (2004) performed a study in the matrix induced effect for 16 widespread pesticides, most often identified in monitoring studies in tomato pepper and cucumber, using a basic multiresidue method with GC-ECD or NPD, with out a prior cleanup step. Anomalously high GC responses and subsequently quite high recoveries for many pesticides within the extracts were obtained by a conventional calibration with pesticide answer in ethyl acetate. A more quickly, much less effective, environmentally safer supercritical fluid extraction (SFE) method was evaluated by Garcia et al (1996) more than traditional sonvent extraction techniques 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 (five:7) mixtures to carryout the extraction with supercritical CO2 and HPLC/DAD,GC/ECD and GC/FPD for evaluation. The chosen SFE circumstances have been 300 atm, 500C, 200l of methanol static modifier, 1 minute static time, and dynamic extraction with 15 ml of CO2 and collection in 3 ml of ethyl acetate. Except for imidacloprid, which was not recovered under any on the assessed situations, pesticide recoveries had been greater than 80%. A simplified strategy 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 3 connected metabolites in fruits and vegetables soon after extraction in the sample with methanol followed by gel permeation chromatography (GPC) or GPC with on-line Nuclear-celite clean up for crops with higher chlorophyll and/or carotene content material (e.g. cabbage and broccoli). Recovery information have been obtained by fortifying five different crops (apples, broccoli, cabbage, cauliflower and potatoes) at 0.05 and 0.five ppm. Recoveries averaged 93% at each fortification levels. The coefficient of variation from the method at both levels is
Estimation by GC-MS/LC-MS Since the mass spectrometer is capable of achieving larger levels of molecular specificity as compared to the classic GC detectors and can be programmed to look for a number of hundred target ions, GC/MS could be a promising approach for regulatory agencies to discover for monitoring pesticide residues in daily food supply (Cheng et al, 1994). Cheng et al (1994) reported a multiresidue approach employing 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 were amongst 46 and 108% at the 0.five mg/kg fortification level of each pesticide in apples, cabbages, cucumbers and grapes. Coefficients of variation have been in between 0.7 and 19%, with an average of 7.5%. The estimated limits of detection from the pesticides within the crops have been 0.1-0.05 mg/kg, except that captan had limit of detection in the crops larger than 0.5 mg/kg. A method depending on 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 various sorts of fruits and vegetables .twelve carbamates added to vegetable components have been extracted with methanol using a homogenizer followed by filtration , an aliquot from the homogenate equivalent to 5 g of the vegetable material was suitably diluted with water and passed via a 1 Carbograpg 1 extraction cartridge. Carbamates have been eluted by passing by means of the cartridge six ml of a CH2Cl2/CH3OH (80:20 v/vegetables) mixture. Recovery in the analytes was far better than 80%, irrespective on the variety vegetable matrix to which the analytes had been added. A strategy employing 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 were determined by Fillion et al (1995) in fruits and vegetables utilizing acetonitrile as extracting solvent as well as 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 were obtained by fortifying 3 matrixes (pear, carrots and bananas) at 0.1-0.five ppm. Blasco et al (2004) utilised a quantitative matrix solid-phase dispersion and liquid chromatographyatmospheric pressure chemical ionization mass spectrometry (LC-APCI-MS) method for the simultaneous analysis of dithiocarbamates and their degradation goods in crops. Typical recoveries varied from 33 to 109%, and relative regular deviation was among four and 21% with limits of quantification ranged from 0.25 to two.five mg/kg. A multiresidue analysis for the determination on the 101 pesticides, including organophosphorus, organochlorine and nitrogen-containing pesticides, in crops by gas chromatography with mass selective detector was performed by Chun et al (2003). Analysis was performed in the selected-ion monitoring mode. Samples have been spiked with pesticides at 0.1-1.0 mg/kg. The recoveries of 90% from the pesticides wee among 70 and 110%; however, the recoveries of acephate and folpet were really poor, i.e.,
Proposed strategy of operate Standardisation of multiresidue analytical techniques of pesticides
Analytical standard of chosen pesticides belonging to various 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 research have been collected from various sources as follows: Sl No.Name in the pesticidesPurity %Source Organochlorine 1?-HCH99.5EPA two?-HCH99.5EPA 3?-HCH99.5EPA four?-HCH99.5EPA 5OP-DDT99.7EPA 6PP-DDT99.7EPA 7OP-DDD99.7EPA 8PP-DDE99.7EPA 9?-endosulfan99.0Excel ten?-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 remedy: Stock normal remedy of different pesticides are to be ready in distilled hexane/acetone and diluted suitably to serve as operating standard and to check the mindividual chromatographic peaks for their suitability for multiresidue evaluation. four.1.2Preparation of mixed standard solytion: from the individual common options a mixed normal remedy is to be ready for approach mdevelopment and decontamination research. 4.1.3Extraction and cleanup In the overview of literature 3 techniques proposed by Kole et al (1998), Nakamura et al (1994) and Obana et al (2001) have been selected to conduct the extraction and cleanup process exactly where each the liquid-liquid as well as a solid-phase extraction using a cartridge column will likely be in comparison to develop a rapidly,simpler and cost-effective strategy to screen a wide array of pesticides. 4.1.4Estimation of pesticide multiresidue A gas chromatograph coupled with an Electron Capture Detectore (ECD) and Nitrogen Phosphorus Detector (NPD) would be to be utilised for estimation on the pesticide residues. The operating circumstances will also be studied as stated inside the chosen 3 approaches. 4.1.5standardisation in the mathod: The selected strategy wil be standardized by conducting a recovery study with all the mixed standard by spiking within the fruits and vegetables. 4.2Monitoring of pesticide residues: 4.two.1Sampling programme: Typa of sample: fruits (Mango and Banana) and vegetables (Tomato, Chilli, Caulioflower, Cabbage). Sampling place: From 2 reputed wholesale markets like.. of West Bengal. Frequency and duration of sampling: Once in each month for one particular 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 research The pesticides are to be selected around the basis of their larger 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.3.1Decontamination processes to be followed: four.three.1.1Washing with water: Chopped samples will likely be taken within a tray containing water as well as the material is going to be gently rubbed with water for about one minute and also the water will probably be decanted or it is rinsed beneath operating tap water for 130 sec., with gentle rotation by hand . washing is to be repeated twice or thrice. 4.3.1.2Salt water washing: Chopped samples will likely be dipped within a beaker containing 2% or 55 sodium chloride answer. After 10-15 minutes the plant samplws is going to be gently rubbed by hand in salt solution and salt water will probably be decanted. Then the samples will be washed in water. 4.3.1.3 Boiling/Cooking: Unwashed samples wil be chopped and boiled within a beaker till the water is completely evaporated covering the containr with or with no lid. Samples is usually to be permitted to cool. 4.three.1.4 Mixture in the above approaches like soak in water for 15 min., rinse with water, reduce into pieces and boiled in water 4.3.1.5Wash with soap resolution, rinse with water.
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