scholarly journals Rapid Method for Trace Determination of Organochlorine Pesticides and Polychlorinated Biphenyls in Yogurt

2002 ◽  
Vol 85 (5) ◽  
pp. 1181-1186 ◽  
Author(s):  
Cristina Yagüe ◽  
Antonio Herrera ◽  
Agustín Ariño ◽  
Regina Lázaro ◽  
Susana Bayarri ◽  
...  
Keyword(s):  
Polychlorinated Biphenyls ◽  
Organochlorine Pesticides ◽  
Reversed Phase ◽  
Electron Capture Detection ◽  
Trace Determination ◽  
Neutral Alumina ◽  
Relative Standard ◽  
Repeatability And Reproducibility ◽  
Concentration Levels

Abstract A new multiresidue method was developed for the analysis of 19 organochlorine pesticides and 6 polychlorinated biphenyls in yogurt. The sample was extracted twice with acetone by homogenization with an Ultra-Turrax dispersing unit, and the combined extracts were filtered. The extract was then purified by reversed-phase C18 columns and subjected to further cleanup with neutral alumina columns. The residues were determined by gas chromatography with electron capture detection. After the method was optimized, it was validated by determination of recovery percentages, precision (repeatability and reproducibility), and sensitivity (detection and quantitation limits) with yogurt samples fortified at 10 and 1 μg/kg concentration levels. The recovery of 23 organochlorine residues ranged from 77 to 95% at a level of 10 μg/kg, from 74 to 102% at a level of 1 μg/kg, and between 54 and 61% for dieldrin and α-endosulfan. The method is repeatable and reproducible, with relative standard deviation values <19% for all residues except dieldrin. Detection and quantitation limits were between 0.02 and 0.62 μg/kg. The analytical method proposed was quick, accurate, repeatable, and reproducible for the determination of organochlorine residues in yogurt samples.

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 Multiresidue Determination of Organochlorine Pesticides and Polychlorinated Biphenyls in Milk by Gas Chromatography with Electron-Capture Detection after Extraction by Matrix Solid-Phase Dispersion

2001 ◽  
Vol 84 (5) ◽  
pp. 1561-1568 ◽  
Author(s):  
Cristina Yagüe ◽  
Susana Bayarri ◽  
Regina Lázaro ◽  
Pilar Conchello ◽  
Agustín Ariño ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Polychlorinated Biphenyls ◽  
Organochlorine Pesticides ◽  
Electron Capture ◽  
Analytical Method ◽  
Solid Phase ◽  
Electron Capture Detection ◽  
Matrix Solid Phase Dispersion ◽  
Phase Dispersion ◽  
Repeatability And Reproducibility

Abstract A multiresidue analytical method based on matrix solid-phase dispersion was developed to analyze liquid milk for 22 organochlorine pesticides (OCPs) and 6 polychlorinated biphenyls (PCBs). Initial extraction is performed by loading 3 mL milk onto a 2.0 g octadecyl (C18)-bonded silica cartridge with n-hexane as the eluant. Neutral alumina column chromatography with sodium sulfate as the drying agent is used for further cleanup. The eluate is concentrated to 0.5 mL, and target analytes are determined by capillary gas chromatography with electron-capture detection. The optimized method was validated by determining accuracy (recovery percentages), precision (repeatability and reproducibility), and sensitivity (detection and quantitation limits) from analyses of milk samples fortified at 10 and 1 μg/L levels. Average recoveries were between 74 and 106% for all residues except β-HCH, β-endosulfan, and endosulfan sulfate. Both repeatability and reproducibility relative standard deviation values were &lt; 22% for all residues. Detection limits ranged from 0.02 to 0.12 μg/L and quantitation limits were between 0.02 and 0.62 μg/L. The proposed analytical method may be used as a fast and simple procedure in routine determinations of OCPs and PCBs in milk.

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.

scholarly journals Determination of Six Pesticides in the Medicinal Herb Cordia salicifolia by Matrix Solid-Phase Dispersion and Gas Chromatography/Mass Spectrometry

2009 ◽  
Vol 92 (4) ◽  
pp. 1184-1189 ◽  
Author(s):  
Pedro Henrique Viana De Carvalho ◽  
Vanessa De Menezes Prata ◽  
Pricles Barreto Alves ◽  
Sandro Navickiene
Keyword(s):  
Extraction Method ◽  
Solid Phase ◽  
Gas Chromatography Mass Spectrometry ◽  
Neutral Alumina ◽  
Appetite Suppressant ◽  
Matrix Solid Phase Dispersion ◽  
Phase Dispersion ◽  
Relative Standard ◽  
Concentration Levels

Abstract A simple and effective extraction method based on matrix solid-phase dispersion was developed for acephate, chlorpropham, pyrimicarb, bifenthrin, tetradifon, and phosalone in leaves of the medicinal plant Cordia salicifolia, whose extracts are commercialized in Brazil as diuretic, appetite suppressant, and weight loss products. The determination method was GC/MS with selectedion monitoring. Different parameters of the method were evaluated, such as type of solid phase (C18, alumina, silica gel, and Florisil) and the amount of solid phase and eluent (dichloromethane, ethyl acetate, chloroform, and cyclohexane). The best results were obtained using 0.5 g herb sample, 0.5 g neutral alumina as the dispersant sorbent, 0.5 g C18 as the cleanup sorbent, and cyclohexanedichloromethane (3 + 1, v/v) as the eluting solvent. The method was validated using herb samples fortified with pesticides at different concentration levels (0.3, 0.5, and 1.0 mg/kg). Average recoveries (seven replicates) ranged from 67.7 to 129.9, with relative standard deviations between 6.3 and 26. Detection and quantitation limits for the herb ranged from 0.10 to 0.15 and 0.15 to 0.25 mg/kg, respectively.

Extraction and Cleanup for Determination of Polychlorinated Biphenyls in Paper and Paperboard

1973 ◽  
Vol 56 (4) ◽  
pp. 957-961
Author(s):  
Susan J V Young ◽  
Charles Finsterw Alder ◽  
Jerry A Burke
Keyword(s):  
Sulfuric Acid ◽  
Polychlorinated Biphenyls ◽  
Organochlorine Pesticides ◽  
Electron Capture ◽  
Electron Capture Detection ◽  
Acid Digestion ◽  
Paper Sample ◽  
Exhaustive Extraction ◽  
Aroclor 1242

Abstract A procedure is described for the determination of polychlorinated biphenyls (PCBs) in paper and paperboard. PCBs are extracted from the paper sample by reflux with alcoholic KOH. Column chromatography on Florisil is used for cleanup, if needed. Compounds are determined by GLC with electron capture detection, using conditions previously devised for organochlorine pesticides. An exhaustive extraction utilizing sulfuric acid was developed in order to obtain comparative data on extraction effectiveness. Recoveries of Aroclors 1242 and 1254 from fortified paper samples averaged 95.5 and 96.8% with the alcoholic KOH reflux and sulfuric acid digestion extractions, respectively. Aroclor 1242 determined after alcoholic KOH extraction of paperboard was 96% of the amount found after sulfuric acid digestion of comparable samples. Aroclor 1242 had been incorporated into the paperboard during manufacture.

scholarly journals Analysis and Evaluation of 7 Indictor Polychlorinated Biphenyls (PCBs) Residues in Dried Kelp by Gas Chromatography (GC)

2020 ◽  
Vol 165 ◽  
pp. 03044
Author(s):  
Liangliang Tian ◽  
Yongfu Shi ◽  
Dongmei Huang ◽  
Huijuan Yu ◽  
Shuai Wang ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Polychlorinated Biphenyls ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Phase Extraction ◽  
Internal Standard Method ◽  
Neutral Alumina ◽  
Solid Phase Extraction Cartridge ◽  
Relative Standard

In this study, a special method was developed for the determination of 7 kinds of polychlorinated biphenyls (PCBs) residues in dried kelp by gas chromatography (GC) with electron capture detector (ECD). The PCBs were extracted with hexane/dichloromethane (1/1, v/v) by ultrasonic extraction. Clean-up methods were used by concentrated sulphuric acid, neutral alumina oxide solid phase extraction cartridge and silica solid phase extraction cartridge. The analytical compounds were quantified by an internal standard method. Under optimal experimental conditions, good linearity was observed in the range of 5~200ng/mL, and the correlation coefficients were 0.9993~0.9998. The limit of quantification (LOQ) for target analytical compounds ranged from 6.0 to 7.5μg/kg. At the spiked levels of 10，20，50 μg/kg，the average recoveries ranged from 81.8% to 105% with the relative standard deviations 3.05%～11.2%. The result showed that the proposed method was accurate and could be used for the determination of the PCBs in dried kelp.

Liquid Chromatographic Method for Determination of Diquat and Paraquat Herbicides in Potatoes: Collaborative Study

1993 ◽  
Vol 76 (4) ◽  
pp. 881-887 ◽  
Author(s):  
Brian L Worobey ◽  
◽  
F Béraldin ◽  
G Bruns ◽  
J Embleton ◽  
...  
Keyword(s):  
Ion Pairs ◽  
Collaborative Study ◽  
Reversed Phase ◽  
Negative Control ◽  
Silica Cartridge ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Repeatability And Reproducibility ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method for the determination of diquat and paraquat herbicides/desiccants in potatoes was collaboratively studied in 6 laboratories. Analytes are extracted from 5 g sample with dilute acid by using a microreflux procedure; the hydrolysate is adjusted to pH 9–10 and passed through a disposable silica cartridge for rapid cleanup and preconcentration. Analytes are separated on a reversed-phase LC column and are measured as their heptanesulfonate ion pairs by UV detection. Each collaborator determined diquat and paraquat at 4 levels (0.05,0.1,0.5, and 1.0 ppm) in blind duplicate samples plus 2 blind negative control samples. Potatoes, obtained from each participant’s region, were spiked by the collaborators with unknown aqueous solutions containing no analyte or a mixture of diquat and paraquat standards. Repeatability and reproducibility relative standard deviations (RSDr and RSDR) averaged 17.1 and 29.0%, respectively, for determination of diquat and 10.8 and 29.5%, respectively, for paraquat. For analysis of standard solutions, RSDr and RSDR values were 6.3 and 12.0%, respectively, for diquat and 7.3 and 13.9%, respectively, for paraquat. Accuracy, measured by comparison with true spiking values (absolute recovery) averaged 77.6 and 76.2% for diquat and paraquat, respectively, and ranged from 71.8 to 88.0% for both compounds. The method was adopted first action by AOAC International.

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