scholarly journals Contribution of Sampling to the Variability of Pesticide Residue Data

2004 ◽  
Vol 87 (6) ◽  
pp. 1368-1379 ◽  
Author(s):  
Árpád Ambrus ◽  
Eugenia Soboleva
Keyword(s):  
Pesticide Residue ◽  
Residue Analysis ◽  
Field Trials ◽  
Medium Size ◽  
Relative Standard ◽  
Significant Difference ◽  
Average Residue ◽  
Combined Uncertainty ◽  
Residue Levels ◽  
Characteristic Features

Abstract The uneven distribution of pesticide residues among the treated objects leads to an inevitable variability of pesticide residue levels measured in the samples, which may significantly contribute to the combined uncertainty of the analytical results. A total of 8844 unit-crop residue data derived from 57 lots and 19 field trials were evaluated to determine the characteristic features of residue distribution in unit crops and composite samples. The average residue levels and the corresponding coefficient of variation (CV) values obtained for individual units taken from a given lot showed wide variation from lot to lot. There was no significant difference between the CVs of residue levels in sample sets of various unit crops or composite sample populations of different sizes taken from various crops. The CV values for levels of residues taken from individual lots followed normal distribution. Very good correlation was found between the CVs of the parent and sample populations. The experimentally obtained values were very close to those expected on the basis of the central limit theorem. The estimated typical relative standard uncertainties of sampling medium-size crops for pesticide residue analysis in the cases of sample sizes of 5, 10, and 25 were 37, 25, and 16%, respectively.

scholarly journals Estimation of Measurement Uncertainty in Pesticide Residue Analysis

2001 ◽  
Vol 84 (5) ◽  
pp. 1569-1578 ◽  
Author(s):  
Lutz Alder ◽  
Wolfagang Korth ◽  
Alan L Patey ◽  
Henk A van der Schee ◽  
Siegmar Schoeneweiss
Keyword(s):  
Pesticide Residue ◽  
Pesticide Residues ◽  
Residue Analysis ◽  
Pesticide Residue Analysis ◽  
Proficiency Tests ◽  
Entire Concentration Range ◽  
Dependent Relationship ◽  
Relative Standard ◽  
Residue Concentration ◽  
Standard Deviations

Abstract Proficiency test results from 5 countries involving 61 separate interlaboratory proficiency tests for pesticide residues were examined in this study. A total of 24 different matrixes and 869 relative standard deviations of the mean (or median) pesticide residue concentration were statistically evaluated in relation to the Horwitz function. The aim was to determine whether or not the concentration-dependent relationship described by Horwitz would hold for the much narrower range of chemicals and concentrations covered in routine pesticide residue analysis. Although for fatty (animal-derived) matrixes the variability increased as the concentration decreased in line with the Horwitz equation, the between-laboratories relative standard deviations for nonfatty matrixes (fruit, vegetables, and grain) remained at 25% over the entire concentration range of 1 μg/kg to 10 mg/kg for the pesticides studied. Given these findings, the Horwitz equation remains valid for calculating uncertainties involving pesticide residues in fatty matrixes. However, for pesticide residue analyses involving nonfatty matrixes, a constant relative standard deviation of 25% is more appropriate for calculating uncertainties, particularly when a reported result is assessed against a regulatory limit.

scholarly journals Pesticide Residue Analysis of Vegetables by Gas Chromatography with Electron-Capture Detection

2007 ◽  
Vol 90 (1) ◽  
pp. 263-270 ◽  
Author(s):  
José Fenoll ◽  
Pilar Hellín ◽  
Carmen M Martínez ◽  
Pilar Flores
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Electron Capture ◽  
Residue Analysis ◽  
Electron Capture Detection ◽  
Pesticide Residue Analysis ◽  
Selected Ion Monitoring ◽  
Green Pepper ◽  
Relative Standard ◽  
Residue Levels

Abstract A new and original analytical method was developed for the routine analysis of 28 multiclass pesticide residues in vegetables (green pepper, red pepper, and tomato). The extraction was performed with acetone, and the pesticides were partitioned into ethyl acetatecyclohexane (1 + 1, v/v). Residue levels in vegetables were determined by gas chromatography (GC) with electron-capture detection. Residue identities were confirmed by GC coupled with mass spectrometry in the selected ion monitoring mode. The average recoveries in pepper and tomato obtained for all analytes studied were 67.3 and 123.1%, respectively, with relative standard deviation between 1.8 and 7.0%. The detection limit for the pesticides studied varied from 0.1 to 2.6 μg/kg. The proposed method was applied to the analysis of these compounds in vegetables grown in experimental greenhouses.

scholarly journals Analytical considerations on the use of a fruit-specific and representative matrix in pesticide residue analysis by LC-ESI-MS/MS

2013 ◽  
Vol 11 (7) ◽  
pp. 1112-1131 ◽  
Author(s):  
Anna Stachniuk ◽  
Emilia Fornal
Keyword(s):  
Pesticide Residue ◽  
Calibration Curve ◽  
Multiple Reaction Monitoring ◽  
Residue Analysis ◽  
Pesticide Residue Analysis ◽  
Liquid Chromatography Mass Spectrometry ◽  
Black Currant ◽  
Relative Standard ◽  
Multiple Reaction Monitoring Mode ◽  
Analytical Errors

AbstractOne of the quantification methods frequently applied to pesticide residue analysis in food by liquid chromatography — mass spectrometry (LC-MS) involves matrix-matched calibrations with a representative matrix used for all commodities belonging to one group. This approach, although very practical, is deemed to generate analytical errors. The effect of the application of a representative-matrix calibration curve on the pesticide quantification result was examined. Extractions of 56 pesticides from five soft fruits (strawberries, blackberries, raspberries, black currant and red currant) were carried out using QuEChERS method. Pesticide determinations were performed by LC-MS/MS in multiple reaction monitoring mode. Quantification difference functions and parameters were proposed and calculated. At the concentration of 0.05 mg kg−1 for ca. 90% of examined pesticides the quantification difference arising from the use of a representative matrix calibration curve (raspberries) instead of a specific fruit matrix calibration curve was below 20% for black and red currents, and below 30% and 35% in the case of strawberries and blackberries, respectively. The 25% difference limit was not exceeded for 51 pesticides in black and red currents, 46 pesticides in blackberries and 45 pesticides in strawberries. Quantification difference functions and parameters such as relative standard deviation of corrected process efficiencies were found to be helpful in data-driven decision-making on the applicability of a representative matrix; the former may be also used as a tool for data correction to ensure the reliability and accuracy of analyses.

Residue analysis of fosthiazate in cucumber and soil by QuEChERS and GC-MS

2014 ◽  
Vol 68 (10) ◽  
Author(s):  
Min Wu ◽  
Jiye Hu
Keyword(s):  
Solid Phase ◽  
Residue Analysis ◽  
Field Trials ◽  
Residue Level ◽  
Gas Chromatography Mass Spectrometry ◽  
Dispersive Solid Phase Extraction ◽  
First Order ◽  
First Order Kinetics ◽  
Maximum Residue Level ◽  
Relative Standard

AbstractA convenient method was developed for the determination and validation of fosthiazate in cucumber and soil. The procedure is based on liquid partitioning with acetonitrile followed by dispersive solid phase extraction as the clean-up step, after which samples were analysed by gas chromatography-mass spectrometry (GC-MS). The average recoveries ranged from 91.2 % to 99.0 % with relative standard deviations (RSDs) of less than 6.05 %, at three fortification levels (0.02 mg kg−1, 0.1 mg kg−1, 0.5 mg kg−1) in cucumber and soil, and the limits of quantification (LOQs) for fosthiazate were all established at 0.02 mg kg−1. The proposed method was applied successfully to analyses of the dissipation and residue of fosthiazate in field trials. The dissipation rate of fosthiazate was described using pseudo-first-order kinetics with a half-life of 4.33 days and 4.08 days in soil in Beijing and Shandong, respectively. In the terminal residue experiment, fosthiazate residues in cucumber and soil were clearly below the maximum residue level (MRL, 0.2 mg kg−1) set in China.

scholarly journals Producers’ Perceptions of Public Good Agricultural Practices Standard and Their Pesticide Use: The Case of Q-GAP for Cabbage Farming in Chiang Mai Province, Thailand

2021 ◽  
Vol 13 (11) ◽  
pp. 6333
Author(s):  
Yuichiro Amekawa ◽  
Surat Hongsibsong ◽  
Nootchakarn Sawarng ◽  
Sumeth Yadoung ◽  
Girma Gezimu Gebre
Keyword(s):  
Pesticide Residue ◽  
Residue Analysis ◽  
Agricultural Practices ◽  
Pesticide Use ◽  
Pesticide Analysis ◽  
Chiang Mai ◽  
Department Of Agriculture ◽  
Safety Assurance ◽  
Significant Difference ◽  
Chiang Mai Province

This study examined the effectiveness of Thailand’s Q-GAP initiative in raising cabbage farmers’ awareness regarding food safety assurance and improving their pesticide use practices by comparing 41 Q-GAP-certified and 90 uncertified farmers in Chiang Mai Province, Thailand. The research methods included a questionnaire survey administered to the participating farmers and laboratory pesticide residue testing of their cabbage produce samples. The research found that certified farmers had a significantly more heedful attitude than uncertified farmers toward the effects of pesticide use on the users, consumers, and the environment. This is supported by the higher level of Q-GAP training experiences. Compared to uncertified farmers, a significantly lower proportion of certified farmers also applied either insecticide, fungicide, or herbicide, with significantly less frequencies when including in the analysis those who did not use the particular pesticide. In the pesticide residue analysis, no significant difference was found between the two types of farms regarding the number of farms detected with minimum residue level exceedance in the sample produce and regarding the results of the aggregate organophosphate pesticide analysis. However, it was found that the produce of the uncertified farmers contained significantly more residue in the aggregate synthetic pyrethroid pesticide analysis as compared to that of the certified farmers. These findings indicate the Q-GAP-certified farmers’ progress in process control from earlier Q-GAP studies on compliance. However, considering the limited achievements of certified farmers in pesticide handling and recordkeeping, and those of the Department of Agriculture officers in auditing, there is a need for more governmental efforts, especially in these areas.

scholarly journals Assessment of Pesticide Residue Levels in common Fruits consumed in Lagos State, Nigeria

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Koleayo Omoyajowo
Keyword(s):  
Pesticide Residue ◽  
Sweet Orange ◽  
Gas Chromatography Mass Spectrometry ◽  
Sampling Location ◽  
Agricultural Produce ◽  
Significant Difference ◽  
Lagos State ◽  
Strict Regulation ◽  
Residue Concentration ◽  
Residue Levels

This study examined pesticide residue levels in three fresh fruit varieties commonly consumed in Lagos state, Nigeria. The fruits (apple, watermelon and sweet orange) were collected from various sale points of fruits in three local government areas; Eti-osa (Ajah), Lagos mainland (Oyingbo) and Ifako-ijaiye (Ifako-Ijaiye). Pesticide residue levels were determined using gas chromatography/mass spectrometry (GC-MS). Data obtained from GC-MS were statistically analysed using graph pad prism 6.0 software and compared with WHO/FAO limits. There was no significant difference (P> 0.05) in each fruits obtained per sampling location. Fruits contained pesticides below WHO/FAO limit except for watermelon that had mean pesticide residue concentration for atrazine (0.088-0.133 mg/kg), clothianidin (0.00 - 0.029 mg/kg), omethoate (0.094 - 0.205 mg/kg) and oxamyloxime (0.088 - 0.125 mg/kg) above WHO/FAO MRLs of 0.02, 0.02, 0.01 and 0.03 mg/kg for atrazine, clothianidin, omethoate and oxamyloxime respectively. The presence of pesticides in these fruits calls for strict regulation of the application of pesticides in farms and preservation chambers. This study recommends further investigation of all agricultural produce in order to circumvent contamination and other problems associated with pesticide accumulation and toxicity.

scholarly journals Removal of Matrix Interferences by Nano-MgO and Co-Adsorbents for Accurate Multi-Pesticide Residue Analysis in the Chinese Medicinal Herb, Paeoniae Radix Alba

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Chunyu Wang ◽  
Xinquan Wang ◽  
Jiao Wang ◽  
Shanshan Di ◽  
Zhiwei Wang ◽  
...  
Keyword(s):  
Pesticide Residue ◽  
Solid Phase ◽  
Residue Analysis ◽  
Method Comparison ◽  
Medicinal Herb ◽  
Acetonitrile Solution ◽  
Pesticide Residue Analysis ◽  
Chinese Medicinal Herb ◽  
Relative Standard ◽  
Paeoniae Radix

A simple, accurate, and high-throughput analytical method was developed to detect 123 pesticide residues in Chinese medicinal herb Paeoniae Radix Alba (PRA) by introducing nano-MgO as a highly efficient purification material based on quick, easy, cheap, effective, rugged, and safe (QuEChERS) design concept. Various PRA samples were extracted using 8 mL 0.5% acetic acid-acetonitrile solution and purified by a dispersive solid-phase extraction method with 30 mg nano-MgO, 40 mg primary secondary amine (PSA), and 40 mg octadecylsilane (C18) as the cleanup adsorbents, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). 70.7% of pesticides showed a weak matrix effect after the purification process, indicating that this method can give the precise quantitative analysis of trace pesticides residue. The method was systematically validated under optimal conditions in five different kinds of PRA samples; good linearity was observed in the concentration range of 0.5–250 μg/L or 1–250 μg/L. Pesticide recovery in each sample spiked at concentrations of 20, 50, and 200 μg/kg ranged from 98.0% to 111% and the mean relative standard deviation ranged from 2.72% to 5.70%. Furthermore, the method comparison with the traditional QuEChERS method suggested the feasibility, advantages, and potential application prospect of the present method for the multi-pesticide residue analysis in various PRA samples.

scholarly journals Women’s Economic Empowerment in Vietnam: Performance and Constraints of Female-Led Manufacturing SMEs

2021 ◽  
Vol 14 (6) ◽  
pp. 255
Author(s):  
MinhTam Bui ◽  
Trinh Q. Long
Keyword(s):  
Labor Productivity ◽  
Small And Medium Enterprises ◽  
Manufacturing Sector ◽  
Value Added ◽  
Medium Size ◽  
Formal Sector ◽  
Firm Level ◽  
Average Value ◽  
Significant Difference ◽  
Medium Enterprises

This paper identifies whether there was a performance difference among micro, small and medium enterprises (MSMEs) led by men and by women in Vietnam during the period 2005–2013 and aims to provide explanations for the differences, if any, in various performance indicators. The paper adopts a quantitative approach using a firm-level panel dataset in the manufacturing sector in 10 provinces/cities in Vietnam in five waves from 2005 to 2013. Fixed effect models are estimated to examine the influence of firm variables and demographic, human capital characteristics of owners/managers on firms’ value added, labor productivity and employment creation. We found that men led MSMEs did not outperform those led by women on average. Although the average value added was lower for female-led firms in the informal sector, the opposite was true in the formal sector where women tend to lead medium-size firms with higher value added and labor productivity. The performance disparity was more envisaged across levels of formality and less clear from a gender perspective. Moreover, while firms owned by businessmen seemed to create more jobs, firms owned by women had a higher share of female employees. No significant difference in business constraints faced by women and by men was found.

Residue Analysis of Organophosphorus and Organochlorine Pesticides in Fatty Matrices by Gas Chromatography Coupled with Electron-Capture Detection

2006 ◽  
Vol 61 (5-6) ◽  
pp. 341-346 ◽  
Author(s):  
Jae-Woo Park ◽  
A. M. Abd El-Aty ◽  
Myoung-Heon Lee ◽  
Sung-Ok Song ◽  
Jae-Han Shim
Keyword(s):  
Gas Chromatography ◽  
Electron Capture ◽  
Simple Procedure ◽  
Linear Regression Analysis ◽  
Residue Analysis ◽  
Electron Capture Detection ◽  
Relative Standard ◽  
Wide Range ◽  
Repeatability And Reproducibility

A multiresidue method for the simultaneous determination of 22 organochlorine (OCs) and organophosphorus (Ops) pesticides (including isomers and metabolites), representing a wide range of physicochemical properties, was developed in fatty matrices extracted from meat. Pesticides were extracted from samples with acetonitrile/n-hexane (v :v, 1:1). The analytical screening was performed by gas chromatography coupled with electron-capture detection (ECD). The identification of compounds was based on their retention time and on comparison of the primary and secondary ions. The optimized method was validated by determining accuracy (recovery percentages), precision (repeatability and reproducibility), and sensitivity (detection and quantitation limits) from analyses of samples fortified at 38 to 300 ng/g levels. Correlation coefficients for the 22 extracted pesticide standard curves (linear regression analysis, n = 3) ranged from 0.998 to 1.000. Recovery studies from 2 g samples fortified at 3 levels demonstrated that the GC-ECD method provides 64.4-96.0% recovery for all pesticides except 2,4′-DDE (44.6-50.4%), 4,4′-DDE (51.1-57.5%) and 2,4′-DDT (50.0-51.2%). Both repeatability and reproducibility relative standard deviation values were < 20% for all residues. Detection limits ranged from 0.31 to 1.27 ng/g and quantification limits were between 1.04 and 4.25 ng/g. The proposed analytical method may be used as a simple procedure in routine determinations of OCs and Ops in meat. It can also be applied to the determination of pesticide multi-residues in other animal products such as butter and milk.

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