Determination of Several Chlorinated Pesticides by the AOAC Multiresidue Method with Additional Quantitation of Perthane after Dehydrochlorination: Collaborative Study

1973 ◽  
Vol 56 (3) ◽  
pp. 721-727
Author(s):  
Richard T Krause
Keyword(s):  
Parent Compound ◽  
Collaborative Study ◽  
Heptachlor Epoxide ◽  
Chlorinated Pesticides ◽  
Average Recovery ◽  
Multiresidue Method ◽  
Coefficients Of Variation ◽  
Before And After ◽  
Coefficients Of Variations

Abstract The AOAC multiresidue method for chlorinated pesticides, 29.001–29.017, was studied collaboratively by 7 laboratories. Perthane, heptachlor epoxide, mirex, and dieldrin were determined in apple and cauliflower samples fortified at 2 levels, and Perthane was determined in butterfat samples fortified at 2 levels. Perthane was quantitatively measured before and after a simplified dehydrochlorination procedure. Average recoveries and coefficients of variations for pesticides in the apple samples for both levels were: Perthane 100±10%, heptachlor epoxide 102±14%, mirex 96±9%, dieldrin 101±14%, and Perthane (after dehydrochlorination and recalculation to the parent compound) 100±9%. Average recoveries and coefficients of variation for pesticides in the cauliflower samples for both levels were: Perthane 105±9%, heptachlor epoxide 103± 15%, mirex 103±7%, dieldrin 98±11%, and Perthane (after dehydrochlorination and recalculation) 100±10%. The average recovery for both levels of Perthane (after dehydrochlorination and recalculation) in the butterfat samples was 91±10%. For a spinach sample with field-incurred residues the collaborators found an average of 4.47 ppm Perthane before dehydrochlorination and 5.09 ppm Perthane as the olefin after dehydrochlorination. In most instances, the identities of all the residues were confirmed by TLC. The dehydrochlorination technique has been adopted as official first action.

Multiresidue Gas Chromatographic Method for Determining Organochlorine Pesticides in Meats: Validation Study for Swine and Beef Fats

1985 ◽  
Vol 68 (5) ◽  
pp. 941-944
Author(s):  
James A Ault ◽  
Timothy E Spurgeon ◽  
Douglas S Gillard ◽  
Edward T Mallinson
Keyword(s):  
Organochlorine Pesticides ◽  
Validation Study ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Heptachlor Epoxide ◽  
Average Recovery ◽  
Coefficients Of Variation ◽  
Poultry Fat ◽  
Gas Chromatographic Method

Abstract A validation of a previously studied method for determining organochlorine residues in poultry fat was conducted to extend the usefulness of the method to beef and swine fats. The validation samples consisted of 16 materials all analyzed in duplicate. Fortification levels ranged from 0.02 to 1.2 ppm for a-BHC, lindane, cis- and Irans-chlordane, octachlor epoxide, o,p'- and p,p'-DDT, p,p'-DDE, p,p'-TDE, hexachlorobenzene, heptachlor epoxide, dieldrin, endrin, methoxychlor, mirex, and toxaphene. The average recovery was 101 % with a range of 7 9 - 113%, not including toxaphene. The ranges of coefficients of variation wtreCV. = 0-23.37% and CVX = 3.74-26.19%. The results were comparable to the previous collaborative study of the same method for poultry fat. The extended method has been adopted official first action

Collaborative Study of the Determination of Sorbic Acid in Wine

1975 ◽  
Vol 58 (1) ◽  
pp. 133-135
Author(s):  
Arthur Caputi ◽  
Karen Slinkard
Keyword(s):  
Sorbic Acid ◽  
Collaborative Study ◽  
Thiobarbituric Acid ◽  
The Other ◽  
Ultraviolet Spectrophotometry ◽  
Acid Complex ◽  
Average Recovery ◽  
Colorimetric Measurement ◽  
Coefficients Of Variation

Abstract Eleven collaborators participated in a study of 2 methods for determining sorbic acid in wine. One method utilizes ultraviolet spectrophotometry and the other depends on the colorimetric measurement of a thiobarbituric acid complex. Three different wine types were each spiked with 200, 300, and 400 mg sorbic acid/ L. Average recovery ranged from 97.3 to 107.5% with the thiobarbituric acid method with coefficients of variation from 4.4 to 8.7%. The ultraviolet method gave recoveries from 97 to 103.5% with coefficients of variation ranging from 2.0 to 6.4%. Comments on both methods from collaborators were favorable. Both methods have been adopted as official first action.

Collaborative Study of the Determination of Dichlorophene in Veterinary Preparations by Ultraviolet Spectrophotometry

1972 ◽  
Vol 55 (1) ◽  
pp. 163-165
Author(s):  
Dalia M Gilvydis
Keyword(s):  
Standard Deviation ◽  
Collaborative Study ◽  
Liquid Extraction ◽  
Synthetic Mixture ◽  
Ultraviolet Spectrophotometry ◽  
Average Recovery ◽  
Liquid Liquid Extraction ◽  
Coefficients Of Variation ◽  
Standard Deviations

Abstract Dichlorophene is determined in veterinary preparations by a liquid-liquid extraction and UV quantitation. Eight collaborators each analyzed 4 commercial preparations and one synthetic mixture. The average recovery for dichlorophene in the synthetic mixture is 100.3% with a standard deviation of 2.13. The standard deviations obtained for the 5 samples range from 0.13 to 3.69 with coefficients of variation from 0.69 to 3.43. It is recommended that the method be adopted as official first action.

Collaborative Study on the Determination of Aflatoxins in Cottonseed Products

1969 ◽  
Vol 52 (1) ◽  
pp. 61-72
Author(s):  
Walter A Pons
Keyword(s):  
Collaborative Study ◽  
Systematic Errors ◽  
Average Recovery ◽  
Coefficients Of Variation ◽  
Tlc Plates ◽  
High Degree

Abstract Twelve laboratories collaboratively studied a method for estimating aflatoxins in cottonseed products, using both visual and fluorodensilometric estimation of aflatoxins on TLC plates. Average recovery of total aflatoxins (B1 + B2) added to five products was 85% by visual and 90% by densitometric estimation; average coefficients of variation were 18 and 12%, respectively. Within- and between-laboratory precision was essentially equivalent for both types of measurement, with no significant systematic errors among the laboratories. There was a high degree of correlation between visual and densitometric estimation of aflatoxins.

Multiresidue Gas Chromatographic Method for Determining Organochlorine Pesticides in Poultry Fat: Collaborative Study

1984 ◽  
Vol 67 (2) ◽  
pp. 284-289 ◽  
Author(s):  
James A Ault ◽  
Tim E Spurgeon ◽  
◽  
M M Anderson ◽  
R Bowers ◽  
...  
Keyword(s):  
Chromatographic Method ◽  
Collaborative Study ◽  
Gel Permeation Chromatography ◽  
Accuracy And Precision ◽  
Coefficients Of Variation ◽  
Poultry Fat ◽  
Gel Permeation ◽  
Detector Method ◽  
Gas Chromatographic Method

Abstract A gas chromatographic electron capture detector method is described for the quantitative determination of organochlorine pesticide residues in poultry fat. The samples are rendered and cleaned up using automated gel permeation chromatography. The collaborative samples consisted of 10 fortified samples and one incurred residue sample, all in duplicate. Fortification levels ranged from 0.15 to 1.0 ppm for a-BHC, lindane, cis- and frans-chlordane, octachlor epoxide, o,p' and p,p'-DDT, p,p'-DDE, p,p'-TDE, hexachlorobenzene, heptachlor epoxide, dieldrin, endrin, methoxychlor, mirex, and toxaphene. The average recovery was 91.9% with a range of 81-102%. The ranges of coefficients of variation were: CVo = 3.39-14.79%; CVL = 0-16.6%; and CVx = 5.82-19.0%. The results indicate accuracy and precision comparable to other official methodology. The method has been adopted official first action.

Collaborative Study of a Method for the Determination of Ochratoxin A in Green Coffee

1975 ◽  
Vol 58 (2) ◽  
pp. 258-262 ◽  
Author(s):  
Colette P Levi
Keyword(s):  
Thin Layer ◽  
Ochratoxin A ◽  
Collaborative Study ◽  
Green Coffee ◽  
Average Recovery ◽  
Semiquantitative Determination ◽  
Chromatographic Methods ◽  
Green Coffee Beans ◽  
Coffee Beans

Abstract A method for the semiquantitative determination of ochratoxin A in green coffee has been studied collaboratively by 11 laboratories. The average recovery for the 7 samples spiked at 3 levels of ochratoxin A was 69.1%, ranging from 60.5 to 85.6%. This is comparable to other visual thin layer chromatographic methods of mycotoxin detection. The method has been adopted as official first action for the determination of ochratoxin A in green coffee beans.

Collaborative Study of a Semiautomated Fluorometric Method for the Determination of Reserpine in Tablets

1976 ◽  
Vol 59 (2) ◽  
pp. 289-292
Author(s):  
Mary A Kreienbaum
Keyword(s):  
Vanadium Pentoxide ◽  
Collaborative Study ◽  
Dosage Level ◽  
Fluorometric Method ◽  
Coefficients Of Variation ◽  
Semiautomated Method

Abstract A semiautomated fluorometric method for the determination of resperpine in tablets was collaboratively studied by 7 laboratories. The method is a modification of the semiautomated method of Urbányi and Stober, which involves formation of a fluorogen with vanadium pentoxide. Collaborators were supplied with 3 composites, each from a different dosage level of commercial tablets. The results obtained agreed well with the AOAC manual fluorometric method; coefficients of variation ranged from 0.45 to 2.70%. The method has been adopted as official first action.

Collaborative Study of a Gas-Liquid Chromatographic Method for the Determination of Water-Soluble Menadione (Vitamin K3) in Feed Premixes

1973 ◽  
Vol 56 (5) ◽  
pp. 1277-1280
Author(s):  
Victor W Winkler
Keyword(s):  
Collaborative Study ◽  
Internal Standard ◽  
Water Soluble ◽  
Vitamin K3 ◽  
Menadione Sodium Bisulfite ◽  
Liquid Chromatographic Method ◽  
Coefficients Of Variations ◽  
Liquid Chromatographic ◽  
Pyrolytic Product

Abstract A GLC method for the determination of menadione bisulfite addition products in feed premixes was tested by 8 laboratories. Menadione sodium bisulfite complex (trihydrate) is extracted with methanol containing 1 mg diethyl phthalate/ml as internal standard and injected directly onto a 2% OV-17 (silylated) GLC column. The principle of the method is on-column pyrolysis of menadione bisulfite and subsequent GLC analysis of the pyrolytic product, menadione. The method is simple, rapid, and free from interference. The average recovery values for 4 samples at 16.0, 14.4, 4.0, and 3.6 g/lb ranged from 95.8 to 100.4% with coefficients of variations between 5.5 and 6.5%. The method has been adopted as interim official first action.

Potassium Interferences in Flame Emission Method for Determining Sodium in Fertilizers

1984 ◽  
Vol 67 (5) ◽  
pp. 888-889
Author(s):  
Luis F Corominas ◽  
Roberto A Navarro ◽  
Ruben J Lopez
Keyword(s):  
Analysis Of Variance ◽  
Calibration Curve ◽  
Collaborative Study ◽  
Potassium Content ◽  
Emission Method ◽  
Average Recovery ◽  
Flame Emission ◽  
Aoac Official ◽  
Preliminary Determination

Abstract Several sodium concentrations ranging from 5.2 to 20 ppm at K:Na ratios ranging from 0 to 40 were studied to determine potassium interferences in the AOAC official first action method, 2.147-2.150, for flame emission spectrophotometric (FES) determination of sodium in fertilizers. According to an analysis of variance performed with recoveries of sodium in solution, potassium interference is the same at low (5.2 ppm) or high (20 ppm) sodium concentrations but is different when the K:Na ratio is changed. A Duncan test showed that potassium interference is equivalent only in the adjacent ratios studied (0, 1, 2, 5, 10, 20, 40) and not for larger ranges. We obtained an average recovery of 98.8% using a calibration curve for a K:Na ratio from a preliminary determination with a calibration curve without potassium content. It is essential to know the potassium content of the sample to enable preparation of a calibration curve for correction. We recommend a collaborative study of NPK samples to determine whether to modify the FES method.

Determination of Sevin Insecticide Residues in Fruits and Vegetables

1964 ◽  
Vol 47 (2) ◽  
pp. 283-286
Author(s):  
D P Johnson
Keyword(s):  
Fruits And Vegetables ◽  
Collaborative Study ◽  
Colorimetric Determination ◽  
Average Recovery ◽  
Insecticide Residues ◽  
Chromogenic Agent ◽  
Hydrolysis Of ◽  
Concentration Levels ◽  
Good Agreement

Abstract Collaborative study of a method for Sevin insecticide residues was repeated with apples and lettuce as test crops. The method is based on alkaline hydrolysis of Sevin and colorimetric determination of the resulting 1-naphthol with p-nitrobenzenediazonium fluoborate as chromogenic agent. Data from 5 collaborators were in good agreement with an average recovery of 87.8% at 2 concentration levels. It is recommended that the method be adopted as official, first action.

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