Int J Pharm Pharm Sci, Vol 10, Issue 1, 53-59Original Article


GAS CHROMATOGRAPHIC DETERMINATION OF 23 ORGANOPHOSPHORUS PESTICIDES RESIDUE IN BOTTLE GUARD MATRIX

SUDEEP MISHRA1, LALITESH KR. THAKUR1, NEELAM RICHHARIYA2*

1Institute of Pesticide Formulation Technology, Sector-20, Udyog Vihar, Opp. Ambience Mall, NH-8, Gurgaon, Haryana 122016, India, 2Govt. Indra College Satna Madhya Pradesh 485001, India
Email: neelamsuved@gmail.com

Received: 30 Jun 2017 Revised and Accepted: 22 Nov 2017

ABSTRACT

Objective: To validate in-house QuEChERS method, which scrutinizes and quantify the residue levels of some most frequently used organophosphorus pesticides and to prove a complete workflow for routine multi-residue pesticide analysis in representative bottle guard matrices and study the persistence of 23 organ phosphorus pesticides.

Methods: QuEChERS (quick, easy, cheap, effective, rugged and safe) extraction method was followed. Method validation and residue screening of bottle guard samples were conducted by GC-FPD (Gas Chromatography-Flame Photometric Detector) were used to analyse the presence of pesticides whereas confirmation of pesticides was done by GC-MS (Gas Chromatographic-Mass Spectrometer).

Results: For bottle guard matrix, LOD (limit of detection) and LOQ (limit of quantification) values are lowest for phorate (0.005 mg/kg and 0.015 mg/kg) and highest for parathion-methyl (0.1 mg/kg and 0.3 mg/kg) respectively. Calibration curve, was plotted between an area of 23 pesticide standard mixture against seven different concentration levels of 0.01, 0.02, 0.05, 0.10, 0.20, 0.50, 1.00 mg/kg with regression coefficient (R2) are in the range of 0.978-0.994. The mean recovered amount at 0.05 mg/kg spikeing concentration are in the range of lowest 0.0413 mg/kg to highest 0.0467 mg/kg and relative standard deviation are in the range of lowest 2.2 to highest 8.571.

Conclusion: For ensuring exposure to contaminants, especially by dietary intake, Robust analytical methods were validated for carrying out both research and monitoring programmes and thus for defining limitations and supporting enforcement of regulations.

Keywords: Bottle guard, Pesticides, LOD, LOQ, MRL, QuEChERS

© 2018 The Authors. Published by Innovare Academic Sciences Pvt Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
DOI: http://dx.doi.org/10.22159/ijpps.2018v10i1.21058

INTRODUCTION

The use of pesticides results in the ‘green revolution’ during the 1960s due to which crop losses reduces, yield improved but results in adverse effects on environmental quality and human health [1-5]. Replacing persistent organochlorines pesticides currently organophosphorus (OP’s) Synthetic Pyrithroids (SP’s) and Herbicides are most widely used in the world as an alternative pest control [6-9]. Tetraethyl pyrophosphate (TEPP) was the first OP insecticide, which was developed in Germany during World War Two as a by-product of nerve gas development [10]. OPs are derived from phosphoric acid, which are mostly acute, toxic, degrade in the atmospheric conditions [11].

The Association of Official Analytical Chemists (AOAC) adopted a method which is the internationally recognized procedure for MRM. By gas chromatography (GC) or high-performance liquid chromatography (HPLC) with selective detectors, the analyte determination is performed. International organizations: the European Union (EU) and the Codex Alimentarius Commission of the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) controlled pesticide residues in food at permissible levels by the MRLs, which are established by them [12]. The pesticides studied were chosen based on their widespread use for crop protection [13].

To overcome the drawbacks of the traditional approaches modern sample preparation procedures, like accelerated solvent extraction (ASE) [14], supercritical fluid extraction (SFE) [15], microwave-assisted extraction (MAE), [16] solid phase extraction (SPE) [17], solid phase microextraction (SPME), [18] matrix solid-phase dispersion (MSPD),[19] extraction and QuEChERS (quick, easy, cheap, effective, rugged and safe),[20] have been developed.

Analytical methods designed for multiple pesticide residues present in foodstuffs. Analytical methods capable of accurately measuring extremely small amounts of pesticides are required. QuEChERS (Quick Easy Cheaper Effective Rugged and safe) method in 2003 for pesticide residue analysis, which gives high-quality results in a fast, easy and an inexpensive way. Analytical quality requirements like trueness, precision, sensitivity and selectivity have been met to suit the need for any particular analysis. The QuEChERS method has been validated for hundreds of pesticide residues in many types of foods, and has become Association of Analytical Communities (AOAC) Official Method 2007.01 [21-24].

The present study was undertaken with the objective to validate in-house QuEChERS method which scrutinizes and quantify the residue levels of some most frequently used organophosphorus pesticides on bottle guard. The objective of this research work is to prove a complete workflow solution that can be implemented for routine multi-residue pesticide analysis in representative bottle guard matrices and study the persistence of organophosphorus pesticide in bottle guard.

Gas chromatography (GC equipped Flame Photometric Detector (FPD) or mass spectrometer (MS) has been frequently applied for the analysis of pesticides in food for many years [25-28]. In this paper, we report the laboratory validation and uncertainty measurement of some organophosphorus pesticides in spinach matrix with good selectivity, sensitivity, and cost-effectiveness.

MATERIALS AND METHODS

Chemicals and reagents

Pesticide reference standards (Sigma-Aldrich), ethyl acetate (HPLC grade), n-hexane (HPLC grade), anhy. Na2SO4 (Merck), anhy. MgSO4 (Merck), primary secondary amine (PSA), (Agilent Technologies), and graphitized carbon black sorbent supelco (Bellefonte, PA, USA).

Extraction and standard stock preparation

Bottle guard sample was purchased from vegetable mandi of Satna (M. P.) and transported to the laboratory. QuEChERS (quick, easy, cheap, effective, rugged and safe) method [29] extraction was done. Fifteen-gram sample was weighted homogenized and chopped into a centrifuge tube and ethyl acetate (30 ml) was added for extraction and shaken for 1 min. Na2SO4 (10g) was added and shaken for 30 min by rotospin and centrifuged at about 5 min. Cleaning step was followed according to Lehotay (2007) [30]. Cleaning of 6 ml upper layer extract was done adding 0.9 g anhydrous MgSO4, 0.25 g PSA and 0.25 g activated charcoal and shaken for 1 min into a 15 ml centrifuge tube. The tube was centrifuged and supernatant 4 ml was dried and finally make up to 1 ml for injection in GC-FPD (Gas Chromatography-Flame Photometric Detector) and GC-MS (Gas Chromatographic-Mass Spectrometer).

The stock solution was prepared by Certified Reference Materials (CRM) of individual pesticide weighed approx 2 mg, in 10 ml volumetric flask, which was dissolved in few drops of HPLC grade acetone and filled up to the mark of standard volumetric flask with HPLC grade hexane. Standard stock solution and working standards were stored in deep freezer at −20 °C. 23 organophosphorus commonly used viz anilophos, chlorfenvinfos, chlorpyrifos, chlorpyrifos-methyl, dichlorvos, ethion, malathion, parathion-methyl, monocrotophos, phorate, profenofos, quinolphos, trizophos, fenitrothion, phosalone, paraxon-methyl, fenamiphos, edfinphos, dimetoate, diazinon, fenthion, parathion and phosphamidon, standard solution mixture was prepared at seven different concentration levels of 0.01, 0.02, 0.05, 0.10, 0.20, 0.50, 1.00 mg/kg, All pesticides are sensitive for FPD detector. Seven different concentration levels were prepared for calibration and recovery tests. Fig. 1, shows the standard mix. Chromatogram of 23 organophosphorus pesticides at 0.5 ppm concentration.

Fig.1: Standard mix chromatogram of 23 organ phosphorus pesticides at 0.5 ppm concentration

Instrument conditions

GC-FPD

Shimadzu makes GC-FPD (GC-QP 2010 model) with the AOC-20S auto sampler. DB-5MS fused silica capillary column was used for analysis. Oven temperature programming of 100 °C as initial temperature for 2 min followed by a ramp rate of 25 °C/min up to 200 °C for 5 min., 4 °C/min up to 230 °C for 2 min and 20 °C/min up to a final temperature of 280 °C with a hold time of 5 min. The injector was set at 250 °C whereas detector at 290 °C. Sampling rate 40 msec, injection volume 1.0 micro litre and 0.5 min equilibrium time. Split Ratio 10:1 was applied. Helium was used as makeup gas and also as carrier gas at a flow rate of 1.23 ml/min. H2 flow rate 85 ml/min with air flow 110.0 ml/min.

GC-MS

GC Model 7890A (Agilent Technologies) with a mass detector (EI mode). DB-5MS fused silica capillary column was used. Oven programming of initial temperature 50 °C for 2 min followed by a ramp rate of 8 °C/min up to a temperature of 280◦C with a hold time of 10 min, total run time 40.75 min. The injector was set at 280 °C. The interface, ion source and quadrapole temperatures were set at 280 °C and 230 °C and 150 °C respectively. Electron impact (70ev) ionization mode with solvent delay time 3 min. The instrument was operated in scan mode. Sampling rate 40 msec, injection volume 1.0 micro litre and 0.5 min equilibrium time. Concentrated extract 1 microlitre was injected in splitless mode. Helium was used as makeup gas and also as carrier gas at a flow rate of 1 ml/min.

RESULTS AND DISCUSSION

Method validation and residue screening of bottle guard samples were conducted by GC-FPD for the presence of pesticides whereas concentrated samples were analyzed by GC-MS in full scan mode for further confirmation of pesticides. Matching of retention time (RT) and mass spectrum (MS) data of the sample peak with that of the standard, confirms identification of the pesticides present in the sample. Final quantification was carried out on GC-FPD. Laboratory method validation of the method was carried out on bottle guard matrix for 23 organ phosphorus pesticides.

Pesticides taken for study

23 organ phosphorus pesticides which are commonly used in India viz anilophos, chlorfenvinfos, chlorpyrifos, chlorpyrifos-methyl, dichlorvos, ethion, malathion, parathion-methyl, monocrotophos, phorate, profenofos, quinolphos, trizophos, fenitrothion, phosalone, paraxon-methyl, fenamiphos, edfinphos, dimetoate, diazinon, fenthion, parathion and phosphomidon are considered for the study. The premilinary screening was done to find out the best chromatographic techniques which can be used in terms of peak shape, response and LOD/lOQ. All 23 pesticides gave good response for FPD detector which can be used for quantification and confirmation by GC-MS.

Method development and validation

For ensuring a robust method, method development and validation parameters, are-Recovery, Selectivity (Specificity), Calibration, Repeatability, Reproducibility, Limit of Detection (LOD), Limit of Quantitation (LOQ). System performance experiment was performed by injecting six consecutive injections at the beginning [31].

Limit of detection and limit of quantification

LOD and LOQ will be measured by using EPA method as it is simple, easy and practical to implement [32, 33]. Limit of detection (LOD) and Limit of quantification (LOQ) was calculated as the lowest concentration a pesticide in a selected matrix which gave the signal to noise (S/N) ratio of approximately equals to 3 and 10 respectively. To measure the LOD, peak to peak noise of blank matrix (bottle guard) at or around the retention time of individual pesticides, the chromatogram of the standard mixture is noted and averaged for three replicates.

The concentration of the individual pesticide is calculated (in µg/g) from the matrix spiked chromatogram which could produce the signal equal to three times of blank matrix. LOQ is calculated by multiplying the LOD value by factor 3 round of two decimal place value. Measured method LOD, LOQ and the relevant legislative limits (MRLs) and ADI [34] are listed in table 1. With the present method, all 23 organophosphorus pesticides for the study presented LOD and LOQ were in the range of below MRL. From table 1, it was observed that for bottle guard matrix, LOD value is lowest for phorate (0.005 mg/kg) and highest for parathion-methyl (0.1 mg/kg) whereas LOQ value is lowest for phorate (0.015 mg/kg) and highest for parathion-methyl (0.3 mg/kg). MRL values of phorate is lowest (0.05 mg/kg) and highest for malathion (3.0 mg/kg) whereas ADI values for diazenon, malathion, phasalone are highest (0.02 mg/kg) and lowest for fenthion, monocrotophos (0.0005 mg/kg). MRL values for some pesticides like chlorpyrifos-methyl, quinolphos, fenamiphos, profenophos, trizophos, edfinphos, anilophos are not available whereas ADI values are not available for monocrotophos, paraxon-methyl, parathion, chlorfenvinphos, quinolphos, fenamiphos, profenophos, ethion, trizophos edifenphos and anilophos.

From LOD and LOQ values it is observed that LOQ is lower than the MRL value as given in PFA (Prevention of Food Adulteration) agency. The method is reliable only if the LOQ value should be always lesser than MRL value of pesticide. Therefore the method can be applicable for the similar type of pesticides and matrix taken for study.

Table 1: Shows class, retention time (R. T), limit of detection (LOD), limit of quantification (LOQ), maximum residues limits (MRL) and acceptable daily intake (ADI) of Organophosphorous pesticide spiked in bottle guard matrix by GC-FPD

S. No. Organophosphorous pesticides R. T LOD (mg/kg) LOQ (mg/kg) MRL (mg/kg) ADI (mg/kg/day)
1 Dichlorvos 5.49 0.007 0.021 0.15 0.004
2 Monocrotophos 9.16 0.03 0.09 0.2 NA
3 Phorate 9.44 0.005 0.015 0.05 0.0005
4 Dimetoate 9.86 0.04 0.12 2 0.002
5 Diazinon 10.43 0.06 0.18 0.50 0.02
6 Paraxon-methyl 11.22 0.05 0.15 0.2 NA
7 Phosphomidon 12.03 0.05 0.15 0.2 0.004
8 Chlorpyrifos-methyl 12.44 0.02 0.06 NA 0.01
9 Parathion methyl 12.67 0.1 0.3 1.00 0.003
10 Fenitrothion 13.61 0.03 0.09 0.30 0.005
11 Malathion 13.88 0.01 0.03 3.00 0.02
12 Chlorpyrifos 14.25 0.02 0.06 0.20 0.01
13 Fenthion 14.25 0.03 0.09 1 0.0005
14 Parathion 14.43 0.01 0.03 0.5 NA
15 Chlorfenvinfos 15.95 0.04 0.12 0.5 NA
16 Quinolphos 16.42 0.01 0.03 NA NA
17 Fenamiphos 17.86 0.02 0.06 NA NA
18 Profenofos 18.58 0.03 0.09 NA NA
19 Ethion 20.93 0.01 0.03 1.00 NA
20 Trizophos 21.60 0.02 0.06 NA NA
21 Edfinphos 21.99 0.01 0.03 NA NA
22 Anilophos 24.15 0.05 0.15 NA NA
23 Phosalone 25.74 0.02 0.06 1 0.02

Fig. 2a-b: Calibration curve of 23 organophosphorus pesticides mixture at 0.01, 0.02, 0.05, 0.1, 0.2, 0.5, 1 ppm conc level

Linearity

The calibration curve of GC-FPD instrument are created at seven levels i. e (matrix match) prepared by spiking 23 pesticides standard mixture solution at different concentration levels and injected in triplicate. Fig. 1 and 2 shows calibration curve, plotted between an area of 23 pesticide standard mixture against seven different concentration levels of 0.01, 0.02, 0.05, 0.10, 0.20, 0.50, 1.00 mg/kg with regression coefficient (R2) are in the range of 0.978-0.994. edifenphos with lowest (R2)0.978 and monocrotophos with highest (R2) 0.9974, rest all pesticides coefficient of regression lies between these value. Fig. 1 and 2 shows calibration curve of 23 organophosphorus pesticides mixture of concentration 0.01, 0.02, 0.05, 0.1, 0.2, 0.5, 1.0 mg/kg in GC-FPD with coefficient of regression (R2). Before starting any analysis work in the gas chromatography, it should be sure that the instrument response should be checked. As the coefficient of regression values lies near to one, shows instrument was ready to work.

Recovery

Method trueness was assessed by recovery studies using bottle guard matrix spiked at 0.05 ppm concentration level and injected in three individually prepared replicates. Spiking of samples occurred prior to sample preparation, recovery, standard deviation and relative standard deviation (% RSD) are calculated in table 2 which shows recovery, standard deviation and relative standard deviation for organophosphorus pesticides. From table 1, it is observed that mean recovered amount at 0.05 mg/kg spike concentration of 23 pesticides mixture of organophosphorus in bottle guard matrix are in the range of 0.0413 mg/kg to 0.0467 mg/kg and it is observed that highest recovery percent is for chlorpyrifos (92.67 %) and lowest recovery percent is for ethion (82.67%) rest pesticides recovery percent in between the range whereas relative standard deviation are in the range of 2.2 to 8.571 values lies below codex permissible limit of 15.

Fig. 3: GC-FPD chromatogram representing a matrix of okra sample

Table 2: Shows recovery, mean recovery, standard deviation (S. D) and relative standard deviation (RSD) of organophosphorus pesticides from spiked bottle guard matrix at 0.05 ppm

R1 R2 R3
S. No. Pesticide RT Spiking conc. Amount recovered Recovered percent Amount recovered Recovered percent Amount recovered Recovered percent Mean recovery Mean recovery SD R. S. D
Dichlorvos 5.49 0.05 0.043 86 0.045 90 0.04 80 0.0427 85.33 0.0025 5.859
Monocrotophos 9.16 0.05 0.043 86 0.044 88 0.045 90 0.0440 88.00 0.001 2.273
Phorate 9.44 0.05 0.045 90 0.042 84 0.043 86 0.0433 86.67 0.0015 3.462
Dimetoate 9.86 0.05 0.047 94 0.046 92 0.043 86 0.0453 90.67 0.0021 4.632
Diazinon 10.43 0.05 0.043 86 0.048 96 0.046 92 0.0457 91.33 0.0025 5.474
Paraxon-methyl 11.22 0.05 0.043 86 0.04 80 0.043 86 0.0420 84.00 0.0017 4.048
Phosphomidon 12.03 0.05 0.044 88 0.046 92 0.045 90 0.0450 90.00 0.001 2.222
Fenthion 12.25 0.05 0.045 90 0.044 88 0.043 86 0.0440 88.00 0.001 2.273
Chlorpyrifos-methyl 12.44 0.05 0.048 96 0.046 92 0.045 90 0.0463 92.67 0.0015 3.237
Parathion methyl 12.67 0.05 0.04 80 0.046 92 0.043 86 0.0430 86.00 0.003 6.977
Fenitrothion 13.61 0.05 0.04 80 0.047 94 0.043 86 0.0433 86.67 0.0035 8.077
Malathion 13.88 0.05 0.041 82 0.046 92 0.048 96 0.0450 90.00 0.0036 8.000
Chlorpyrifos 14.25 0.05 0.048 96 0.045 90 0.047 94 0.0467 93.33 0.0015 3.214
Parathion 14.43 0.05 0.043 86 0.048 96 0.046 92 0.0457 91.33 0.0025 5.474
Chlorfenvinfos 15.95 0.05 0.045 90 0.046 92 0.041 82 0.0440 88.00 0.0026 5.909
Quinolphos 16.42 0.05 0.043 86 0.046 92 0.046 92 0.0450 90.00 0.0017 3.778
Fenamiphos 17.86 0.05 0.043 86 0.046 92 0.048 96 0.0457 91.33 0.0025 5.474
Profenofos 18.58 0.05 0.046 92 0.042 84 0.044 88 0.0440 88.00 0.002 4.545
Ethion 20.93 0.05 0.04 80 0.043 86 0.041 82 0.0413 82.67 0.0015 3.629
Trizophos 21.6 0.05 0.043 86 0.04 80 0.046 92 0.0430 86.00 0.003 6.977
Edfinphos 21.99 0.05 0.04 80 0.046 92 0.047 94 0.0443 88.67 0.0038 8.571
Anilophos 24.15 0.05 0.04 80 0.044 88 0.043 86 0.0423 84.67 0.0021 4.961
Phosalone 25.74 0.05 0.046 92 0.043 86 0.047 94 0.0453 90.67 0.0021 4.632

According to SANCO, recovery values should come within an acceptable range between 70–120%. It always happens that matrix effect was predominant for some pesticides.

To overcome variable matrix effect, the quantification was done using matrix-matched standards prepared in matrix blank. Recovery table shows that all 23 pesticides give lowest approx 82 to highest approx. 92 percent recovery which is according to SANCO guideline. RSD values are also below 10 as per SANCO.

Therefore method can efficiently be used for analysis of similar type of pesticides and matrix taken for study

Selectivity/Sensitivity

NIST library of Gas chromatography-mass spectrometry was used to confirm the presence of pesticides taken for study. Spectra matched with reference spectra of NIST. Presence of pesticides was confirmed by their fragmentation pattern matches with reference spectra of NIST. Some of the reference spectra of pesticide of the group like chlorpyrifos, profenofos are given in fig. 2 and fig. 3 respectively. Table 3 shows mass fragmentation pattern of each pesticide for confirmation in GC-MS. Matrix blank sample of bottle guard (fig. 3), was inspected in GC-FPD for the presence of interfering peaks in close to target retention times observed for all pesticides taken for study.

Table 3: Fragmentation pattern of 23 organophosphorus pesticides taken for study

S. No. Organophosphorous pesticides Qualifier Ions (m/z) S. No Organophosphorous pesticides Qualifier ions (m/z)
Anilophos 226 125 -
Trizophos 257 161 -
Chlorfenvinfos 323 269 267
Fenitrothion 277 260 109
Chlorpyrifos 314 286 197
Phosalone 367 182 -
Chlorpyrifos-methyl 286 125 -
Paraxon-methyl 125 109 263
Dichlorvos 220 109 185
Fenamiphos 303 154 80
Ethion 231 153 -
Edfinphos 310 173 -
Malathion 173 158 -
Dimetoate 125 87 -
Parathion methyl 263 233 125
Diazinone 304 179 152
Monocrotophos 192 164 127
Fenthion 278 125 93
Phorate 260 231 75
Parathion 194 109 67
Profenofos 339 139 97
Phosphomidon 264 127 72
Quinolphos 157 146 118

Repeatability and reproducibility

The method was analysed for recovery studies which were repeated for three times are R1, R2 and R3. Their Mean (M), Standard Deviation (SD) and Relative Standard Deviation (RSD) of each pesticide were calculated as shown in table 2. Similarly from table 4. three repeatable injections for 23 organophosphorus pesticide at seven concentration level i. e 0.01, 0.02, 0.1, 0.2, 0.5, 1 ppm shows that area of three injections of each pesticides mixture are repeatable at all concentration with relative standard deviation lies from 0.4 for parathion-methyl and chlorpyrifos to 4.2 for paraxon methyl and anilophos at 0.2 ppm concentration. It is observed that all the three injections are repeatable at different conc. with Relative Standard Deviations lies<= 5. Instrument injection precision was tested for both retention time and peak area for all target compounds by subsequent injections (n=3) of low concentration level (0.01) standard solution mixture for GC-FPD. Instrument injection precision for retention time was below 0.5% for all compounds. According to SANCO requirements, <20% was set as acceptance criteria for the target compounds and matrices. Therefore the method adopted for analysis of pesticide residue is reliable for a similar type of pesticides and matrices.

As the method is well suitable for the qualitative and quantitative determination of pesticides in bottle guard matrix. A similar type of result can also be seen in bottle guard like other matrices. Many studies have been carried out for monitoring pesticides in various matrices. A study conducted in tomato, banana and wheat matrices, for the analysis of 25 pesticides of various groups, by a single method, single run and single ECD instrument [35-37].

Table 4: Shows repeatability, standard deviation (SD), relative standard deviation (RSD) of organophosphorus pesticides at 0.5 ppm concentration

Pesticide

OP Mix

 RT Area1 Area2 Area3 Average area  SD RSD
Conc-0.5 ppm  
Dichlorvos 5.40 6011349.3 6006880.1 6040900.1 6019709.8 18486.9 0.3
Monochrotofos 8.96 1182863.4 1180992.6 1183551.6 1182469.2 1324.3 0.1
Phorate 9.34 12260776.2 12268967.9 12275272.0 12268338.7 7268.4 0.1
Dimethoate 10.00 8435229.7 8410649.8 8578248.7 8474709.4 90506.0 1.1
Diazinon 10.50 12243666.7 12430952.5 12368525.2 12347714.8 95361.4 0.8
Paraxon Methyl 11.24 634866.8 625034.9 638437.3 632779.7 6940.7 1.1
Phosphomidon 12.03 852218.5 889402.3 938065.1 893228.6 43051.0 4.8
Chlorpyrifos Methyl 12.35 7878194.2 7953549.2 8064050.8 7965264.7 93480.5 1.2
Parathion Methyl 12.69 10609289.7 10686466.0 10833056.1 10709603.9 113663.4 1.1
Fenitrothion 13.62 10343503.5 10446194.7 10544864.9 10444854.4 100687.4 1.0
Malathion 13.85 8561172.8 8607688.2 8702414.5 8623758.5 71979.1 0.8
Chlorpyrifos 14.14 9724404.9 9870959.6 9910863.7 9835409.4 98181.4 1.0
Fenthion 14.40 12873700.5 13070325.3 13061142.0 13001722.6 110965.4 0.9
Parathion 14.57 12416931.0 12569078.4 12538812.3 12508273.9 80539.8 0.6
Chlorfenvinfos 16.06 2558500.4 2576435.6 2657833.8 2597589.9 52937.8 2.0
Quinalphos 16.37 13035836.8 13188248.6 13098370.6 13107485.3 76613.6 0.6
Fenamifos 18.06 4304599.7 4431810.2 4259665.8 4332025.2 89289.1 2.1
Profenofos 18.52 2117843.4 2156272.4 2239560.6 2171225.5 62221.1 2.9
Ethion 20.87 20771770.0 20905654.9 20842785.3 20840070.1 66983.7 0.3
Triazofos 21.65 10775845.0 10852581.4 10734936.7 10787787.7 59724.7 0.6
Edifinfos 22.09 777446.1 766196.0 833851.3 792497.8 36252.2 4.6
Anilofos 24.21 3877620.4 3979122.0 4148026.1 4001589.5 136595.8 3.4
Phosalane 24.80 7766225.6 7752598.1 7973108.7 7830644.1 123565.9 1.6

CONCLUSION

Determination of pesticide residues in vegetables is necessary for ensuring human exposure to contaminants, especially by dietary intake, does not exceed acceptable levels for health. Robust analytical methods were validated for carrying out both research and monitoring programmes and thus for defining limitations and supporting enforcement of regulations. Reproducible analytical methods are required to allow the effective separation, selective identification, and accurate quantification of pesticide analytes at low levels in food-stuffs including foods of plant and animal origin.

The qualitative and quantitative determination of pesticide residue in vegetables provide following informations.

Vegetables are commonly consumed throughout the region, therefore it is important to know the toxicity pertains in it. Food and Agriculture Organization of the World Health Organization (FAO/WHO) and the European Union (EU), requires an adequate methodology for enforcement of maximum residue limits (MRL) and acceptable daily intake (ADI) values.

The advantage of this approach would be rapidity and ease of analysis, higher recoveries, good sensitivity, low limit of detection and less reagent requirement. Commonly used pesticides such as organochlorine, organophosphorus, synthetic pyrethorides and herbicides will be monitored in matrices. Different extraction techniques will be followed by a selection of most precise techniques with higher recovery percentage.

ACKNOWLEDGEMENT

The author is thankful to Director and Incharge Analytical to provide the necessary facilities to complete this work.

AUTHOR CONTRIBUTIONS

Author name Sudeep Mishra is a Ph. D. student under Dr. Smt. Neelam Richhariya. The work relates to Ph. D work of author under the guidance of Dr Neelam Richhariya.

CONFLICT OF INTERESTS

Declared none

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