scholarly journals Validation of a Rapid Multiresidue Method for the Determination of Pesticide Residues in Vine Leaves. Comparison of the Results According to the Different Conservation Methods

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1176
Author(s):  
Salem Hayar ◽  
Rawan Zeitoun ◽  
Britt Marianna Maestroni
Keyword(s):  
Vitis Vinifera ◽  
Pesticide Residues ◽  
Quechers Method ◽  
Systemic Fungicides ◽  
Preservation Methods ◽  
Relative Standard ◽  
Repeatability And Reproducibility ◽  
Comparison Of The Results ◽  
Chemical Groups

The QuEChERS method was applied to the determination of pesticide residues in vine (Vitis vinifera) leaves by LC-MSMS. The method was validated in-house for 33 pesticides representing 17 different chemical groups, that are most commonly used in grape production. Recoveries for the pesticides tested ranged from 75 to 104%, and repeatability and reproducibility relative standard deviations (RSDr% and RSDRw%) were less than 20%. The method was applied to the analysis of pesticide residues in 17 market brands of vine leaves processed according to three different preservation methods and sampled from the Lebanese market. Dried vine leaves were more contaminated with pesticide residues than those preserved in brine or stuffed vine leaves. The systemic fungicides were the most frequently detected among all the phytosanitary compounds usually applied to grape production. Brine-preserved and stuffed vine leaves contained lower concentrations of the residues but still contained a cocktail of different pesticides.

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.

scholarly journals Determination of Selected Priority Pesticides in High Water Fruits and Vegetables by Modified QuEChERS and GC-ECD with GC-MS/MS Confirmation

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 417 ◽  
Author(s):  
Maciej Tankiewicz
Keyword(s):  
Water Content ◽  
Fruits And Vegetables ◽  
High Water ◽  
International Agency ◽  
High Water Content ◽  
Vegetable Crops ◽  
Fruit And Vegetable ◽  
Quechers Method ◽  
Relative Standard

A modified quick, easy, cheap, efficient, rugged and safe (QuEChERS) method coupled to gas chromatography with electron capture detector (GC-ECD) was developed for simultaneous determination of selected electronegative pesticides in fruits and vegetables with high water content. The chosen compounds are commonly detected in fruit and vegetable crops, and some of their metabolites have even been found in human urine. In addition, some of them are known or suspected carcinogens according to the International Agency for Research of Cancer. Extraction and clean up parameters were optimized, thus the original QuEChERS method was modified to decrease solvent usage, in accordance with ‘green chemistry’ principles. The proposed methodology was validated in terms of selectivity, specificity, linearity, precision and accuracy. The obtained limits of detection (LODs) for all investigated pesticides ranged from 5.6 µg·kg−1 to 15 µg·kg−1 and limits of quantification (LOQs) from 17 µg·kg−1 to 45 µg·kg−1. The obtained data demonstrated the good reproducibility and stability of the procedure in the tested concentration range up to 10 mg·kg−1, with relative standard deviations (RSDs) lower than 10%. Recoveries for spiked pear samples at LOQ level for each pesticide were from 90% to 107% with RSDs lower than 9.6%. The suitability of the developed procedure was tested on various fruit and vegetable samples available on the market at different seasons. The proposed methodology is applicable for detection and monitoring of selected pesticides not only in fruits and vegetables with high water content, but also in samples containing large amounts of pigments and dyes.

Liquid Chromatographic Method for Determination of Iodine in Milk: Collaborative Study

1993 ◽  
Vol 76 (4) ◽  
pp. 711-719 ◽  
Author(s):  
David Sertl ◽  
William Malone ◽  
◽  
P Beljaars ◽  
C Blake ◽  
...  
Keyword(s):  
Membrane Filter ◽  
Collaborative Study ◽  
Reversed Phase ◽  
Powdered Milk ◽  
Insoluble Material ◽  
Relative Standard ◽  
Repeatability And Reproducibility ◽  
Standard Deviations ◽  
Liquid Chromatographic

Abstract Nine laboratories participated in an AOAC International/ International Dairy Federation collaborative study on a liquid chromatographic (LC) method for determination of iodine in milk. Liquid milk is passed through a 25 000 MW membrane filter to remove protein and insoluble material. Iodine (in the form of iodide) in the clear filtrate is separated by reversed-phase ion-pair LC and is detected electrochemically. Participants analyzed 2 commercial pasteurized whole milks and 5 nonfat dry milk powders in blind duplicate. Each sample was tested in duplicate on 2 days. Repeatability and reproducibility standard deviations (sr and SR, respectively) and repeatability and reproducibility relative standard deviations (RSDr and RSDR, respectively) for determinations of iodine in whole milk (mean recovery, 86.7%) were as follows: sr, 22 μg/L; SR, 22 μg/L; RSDr, 8.2%; and RSDR, 8.3%. For powdered milk (mean recovery, 91 %), the values were as follows: sr, 0.14 μg/g; SR, 0.22 μg/g; RSDr, 9.0%; and RSDR, 12.7%. The method was adopted first action by AOAC International.

Evaluation of an alternative fluorinated chitosan as a QuEChERS adsorbent for pesticide residue analysis in apple samples

2019 ◽  
Vol 11 (27) ◽  
pp. 3460-3466 ◽  
Author(s):  
Qilin Deng ◽  
Liping Sun ◽  
Tao Zhu
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Pesticide Residue ◽  
Pesticide Residues ◽  
High Performance ◽  
Residue Analysis ◽  
Pesticide Residue Analysis ◽  
Quechers Method

In this study, a new and green fluorinated chitosan (trifluoroethyl methacrylate-chitosan (TFEMA-CTS)) was synthesized, and the QuEChERS method was applied for the effective determination of four pesticide residues in apple samples by high performance liquid chromatography.

Gas Chromatographic Determination of Nicotine in Environmental Tobacco Smoke: Collaborative Study

1989 ◽  
Vol 72 (6) ◽  
pp. 1002-1006
Author(s):  
Michael W Ogden
Keyword(s):  
Environmental Tobacco Smoke ◽  
Tobacco Smoke ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
Selective Detection ◽  
Mainstream Smoke ◽  
Relative Standard ◽  
Repeatability And Reproducibility ◽  
Gas Chromatographic Method

Abstract A gas chromatographic method for determination of vapor phase nicotine in environmental tobacco smoke (ETS) was collaboratively studied by 6 laboratories. Nicotine is desorbed from XAD-4 sample tubes with ethyl acetate containing triethylamine and determined by gas chromatography with nitrogen-selective detection. Each collaborator received blind duplicate samples at each of 6 nicotine concentrations. Three concentrations were generated by spiking XAD-4 tubes with known amounts of nicotine; the remaining 3 concentrations were ETS samples obtained in a carefully controlled environmental chamber containing sidestream and exhaled mainstream smoke from 1R4F Kentucky reference cigarettes. Repeatability and reproducibility relative standard deviations ranged from 4.4 to 11.1% and from 7.0 to 11.1%, respectively, for nicotine concentrations evaluated (up to 6 ng/cu m). The method has been adopted official first action.

Determination of Nitrogen Content in Milk by the Kjeldahl Method Using Copper Sulfate: Interlaboratory Study

1988 ◽  
Vol 71 (5) ◽  
pp. 893-898 ◽  
Author(s):  
R Grappin ◽  
William Horwitz
Keyword(s):  
Quality Control ◽  
Nitrogen Content ◽  
Copper Sulfate ◽  
Interlaboratory Study ◽  
Internal Quality ◽  
Relative Standard ◽  
Nitrogen Concentrations ◽  
Kjeldahl Method ◽  
Repeatability And Reproducibility

Abstract Copper sulfate was substituted for mercury as the catalyst in the International Dairy Federation (IDF) Standard 20A:1986 method for the determination of nitrogen content in milk. The substitution was supported by results obtained in an interlaboratory study by 24 laboratories in 12 countries. Each laboratory analyzed 12 test samples of milk as blind duplicates in a double split level design with high, medium, and low nitrogen concentrations. The method protocol requires the concurrent analyses of an ammonium salt solution and a tryptophan solution as internal quality control standards with a minimum nitrogen recovery between 99 and 100% for the former and at least 98% for the latter. The repeatability and reproducibility relative standard deviations are 0.5 and 1%, respectively, for the range 0.35-0.70 g N/100 g. The performance of the laboratories that did not meet the required quality control specifications was clearly poorer than that of those that did meet the specifications.

scholarly journals Determination of the Levels of Polycyclic Aromatic Hydrocarbons in Toasted Bread Using Gas Chromatography Mass Spectrometry

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Amal Al-Rashdan ◽  
Murad I. H. Helaleh ◽  
A. Nisar ◽  
A. Ibtisam ◽  
Zainab Al-Ballam
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Wheat Flour ◽  
Aromatic Hydrocarbons ◽  
Soxhlet Extraction ◽  
Gas Chromatography Mass Spectrometry ◽  
White Wheat ◽  
Relative Standard ◽  
Polycyclic Aromatic ◽  
Repeatability And Reproducibility

Concentration of 16 polycyclic aromatic hydrocarbons (PAHs) in eighteen baked bread samples using gas oven toasting were evaluated in this study. Samples were classified into the following categories: (1) bread baked from white wheat flour, (2) bread baked from brown wheat flour, and (3) sandwich bread baked from white wheat flour. Analysis was performed by GC-MS after Soxhlet extraction of the sample and clean up of the extract. The levels of B[a]P was not detected in ten of eighteen samples. In the rest of the samples, B[a]P are varied from 2.83 to 16.54 g/kg. B[a]A, CHR, B[b]FA, B[k] FA, IP, DB[a,h]A, and B[ghi]P concentrations were found to be less than 10.0 g/kg. However, B[a]P are not detected in original white and brown wheat flour. The total PAHs were varied in the range 1.06–44.24 g/kg and 3.08–278.66 g/kg for H-PAH and L-PAH, respectively. Reproducibility and repeatability of the proposed method was calculated and presented in terms of recovery and relative standard deviations (RSD, %). Recoveries were varied from 72.46% to 99.06% with RSD ± 0.28–15.01% and from 82.39% to 95.01% with RSD ±1.91–13.01% for repeatability and reproducibility, respectively. Different commercialized samples of toasted bread were collected and analyzed.

scholarly journals Kinetic Spectrophotometric Determination of Gemifloxacin Mesylate and Moxifloxacin Hydrochloride in Pharmaceutical Preparations Using 4-Chloro-7-nitrobenzo-2-oxa-1,3-diazole

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Mohammed G. Abdel Wahed ◽  
Ragaa El Sheikh ◽  
Ayman A. Gouda ◽  
Sayed Abou Taleb
Keyword(s):  
Limit Of Detection ◽  
Kinetic Method ◽  
Pharmaceutical Preparations ◽  
Fixed Time ◽  
Spectrophotometric Methods ◽  
Relative Standard ◽  
Significant Difference ◽  
Kinetic Spectrophotometric ◽  
Comparison Of The Results

Simple, sensitive, and accurate kinetic spectrophotometric method was proposed for the determination of gemifloxacin mesylate (GMF) and moxifloxacin hydrochloride (MOX) in pure forms and pharmaceutical preparations (tablets). The method is based on coupling the studied drugs with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) in the presence of alkaline borate buffer. Spectrophotometric measurement was achieved by recording the absorbance at 466 and 464 nm for GMF and MOX, respectively, after a fixed time of 20 and 15 min on a water bath adjusted at 70 ± 5°C for both drugs. The different experimental parameters affecting the development and stability of the color were carefully studied and optimized. The absorbance-concentration plots were linear over the ranges 0.5–8.0 and 2.0–12 μg mL−1for GMF and MOX, respectively. The limit of detection of the kinetic method was about 0.12 (2.47 × 10−7 M) and 0.36 (8.22 × 10−7 M) μg mL−1for GMF and MOX, respectively. The proposed methods have been applied and validated successfully with percentage relative standard deviation (RSD% ≤ 0.52) as precision and percentage relative error (RE% ≤ 1.33) as accuracy. The robustness of the proposed method was examined with recovery values that were 97.5–100.5 ± 1.3–1.9%. Statistical comparison of the results with the reference spectrophotometric methods shows excellent agreement and indicates no significant difference in accuracy or precision.

Sign in / Sign up

Export Citation Format

Share Document