Capillary Gas Chromatographic Determination of Some Chlorobiphenyls in Eel Fat: Interlaboratory Study

1985 ◽  
Vol 68 (4) ◽  
pp. 756-759
Author(s):  
Louis G M Th Tuinstra ◽  
Arie H Roos ◽  
Geziena A Werdmuller
Keyword(s):  
Gas Chromatography ◽  
Standard Deviation ◽  
Coefficient Of Variation ◽  
Capillary Gas Chromatography ◽  
Chromatographic Determination ◽  
Interlaboratory Study ◽  
Analytical Results ◽  
The Mean

Abstract A method for determination of 6 individual chlorobiphenyls in eel fat, based on saponification of the sample and determination with capillary gas chromatography, was studied collaboratively. Eleven laboratories submitted analytical results in duplicate for 6 individual chlorobiphenyls on 2 naturally contaminated eel fat samples. The reproducibility coefficient of variation was about 14% at the 1 mg/kg level for each chlorobiphenyl compound and about 23% at the 0.1 mg/kg level. For each compound, the mean recovery was about 90% with a standard deviation varying from 7 to 9%.

scholarly journals Determination of Glyphosate and Aminomethylphosphonic Acid in Crops by Capillary Gas Chromatography with Mass-Selective Detection: Collaborative Study

2001 ◽  
Vol 84 (3) ◽  
pp. 823-846 ◽  
Author(s):  
Philip L Alferness ◽  
Lawrence A Wiebe ◽  
L Anderson ◽  
O Bennett ◽  
M Bosch ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Capillary Gas Chromatography ◽  
Collaborative Study ◽  
Selective Detection ◽  
Aminomethylphosphonic Acid ◽  
Relative Standard ◽  
The Mean

Abstract A collaborative study was conducted to validate a method for the determination of glyphosate and aminomethylphosphonic acid (AMPA) in crops. The analytes are extracted from crops with water, and the crude extracts are then subjected to a cation exchange cleanup. The analytes are derivatized by the direct addition of the aqueous extract into a mixture of heptafluorobutanol and trifluoroacetic anhydride. The derivatized analytes are quantitated by capillary gas chromatography with mass-selective detection (MSD). The collaborative study involved 13 laboratories located in 5 countries 12 laboratories returned valid data sets. The crops tested were field corn grain, soya forage, and walnut nutmeat at concentrations of 0.050, 0.40, and 2.0 mg/kg. The study used a split-level pair replication scheme with blindly coded laboratory samples. Twelve materials were analyzed, including 1 control and 3 split-level pairs for each matrix, 1 pair at each nominal concentration. For glyphosate, the mean recovery was 91%, the average intralaboratory variance, the repeatability relative standard deviation (RSDr), was 11%, and the interlaboratory variance, the reproducibility relative standard deviation (RSDR), was 16%. For AMPA, the mean recovery was 87%, the RSDr was 16%, and the RSDR was 25% at mg/kg levels.

scholarly journals Liquid Chromatographic Determination of Deoxynivalenol in Baby Food and Animal Feed: Interlaboratory Study

2006 ◽  
Vol 89 (4) ◽  
pp. 1012-1020 ◽  
Author(s):  
Joerg Stroka ◽  
Michelle Derbyshire ◽  
Carsten Mischke ◽  
Massimo Ambrosio ◽  
Katy Kroeger ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
High Performance ◽  
Animal Feed ◽  
Chromatographic Determination ◽  
Baby Food ◽  
Interlaboratory Study ◽  
Relative Standard ◽  
Liquid Chromatographic

Abstract An interlaboratory study was conducted for the determination of deoxynivalenol in baby food and animal feed by high-performance liquid chromatography with UV detection. The study included 14 participants representing a cross section of industry, official food control, and research facilities. Mean recoveries reported ranged from 89% (at 120 g/kg) to 85% (at 240 g/kg) for baby food and from 100% (at 200 g/kg) to 93% (at 400 g/kg) for animal feed. On the basis of the results for spiked samples (blind duplicates at 2 levels), as well as those for naturally contaminated samples (blind duplicates at 3 levels), the relative standard deviation for repeatability (RSDr) in analyses of baby food ranged from 6.4 to 14.0% and in analyses of animal feed, from 6.1 to 16.5%. The relative standard deviation for reproducibility (RSDR) in analyses of baby food ranged from 9.4 to 19.5% and in analyses of animal feed, from 10.5 to 25.2%. The HorRat values ranged from 0.4 to 1.0 and from 0.7 to 1.3, for baby food and animal feed, respectively. The method showed acceptable performance for within-laboratory and between-laboratory precision for each matrix, as required by European legislation.

Gas Chromatographic Determination of Captan, Folpet, and Captafol Residues in Tomatoes, Cucumbers, and Apples Using a Wide-Bore Capillary Column: Interlaboratory Study

1991 ◽  
Vol 74 (5) ◽  
pp. 830-835 ◽  
Author(s):  
Dalia M Gilvydis ◽  
Stephen M Walters
Keyword(s):  
Gas Chromatography ◽  
Electron Capture ◽  
Capillary Column ◽  
Chromatographic Determination ◽  
Interlaboratory Study ◽  
Electron Capture Detection ◽  
Coefficients Of Variation ◽  
Capillary Column Gas Chromatography ◽  
Ppm Level

Abstract An interlaboratory study of the determination of captan, folpet, and captafol in tomatoes, cucumbers, and apples was conducted by 4 laboratories using wide-bore capillary column gas chromatography with electron capture detection. The 3 fungicides were determined using the Luke et al. multlresidue method modified to Include additional solvent elutlon in the optional Florisll column cleanup step used with this method. The crops were fortified with each fungicide at 3 levels per crop. Mean recoveries ranged from 86.2% for a 25.1 ppm level of captan in apples to 115.4% for a 0.288 ppm level of captafol In apples. Interlaboratory coefficients of variation ranged from 3.4% (24.7 ppm folpet) to 9.7% (0.243 ppm captafol) for tomatoes; from 2.8% (2.0 ppm captafol) to 8.2% (24.8 ppm captan) for cucumbers; and from 1.5% (0.234 ppm folpet) to 22.1% (0.266 ppm captafol) for apples.

scholarly journals Liquid Chromatographic Determination of Tilmicosin in Swine Feed at 200–400 mg/kg Level: Interlaboratory Study

1997 ◽  
Vol 80 (6) ◽  
pp. 1156-1160
Author(s):  
Robin S Readnour ◽  
Mark R Coleman ◽  
Mary G Leadbetter ◽  
F Armstrong ◽  
H Campbell ◽  
...  
Keyword(s):  
Chromatographic Determination ◽  
Interlaboratory Study ◽  
Label Claim ◽  
Liquid Chromatographic Determination ◽  
The Mean ◽  
Gradient Liquid Chromatography ◽  
Liquid Chromatographic ◽  
Feed Samples ◽  
Intended Use

Abstract An analytical method for the determination of tilmicosin at 200–400 mg/kg, the intended use concentration range, was evaluated in an interlaboratory study involving 5 laboratories, including the sponsor. The interlaboratory study evaluated the intra- and interlaboratory precision and accuracy of a tilmicosin feed method. The method procedure involved extracting tilmicosin from feed by adding 200 mL extractant to 20 g feed and shaking for 1 h. The extract is filtered and analyzed by gradient liquid chromatography which separates tilmicosin from feed matrix in 30 min. Each laboratory assayed 5 replicates of fortified feed at concentrations of 0,100, 200, 400, and 600 mg/kg. The mean recovery among fortified samples ranged from 81.4 to 98.8%, with a percent coefficient of variation (%CV) ranging from 0.3 to 4.0%. For all blank control feed samples no significant interferences were observed. In addition, each laboratory assayed 5 replicates of medicated feed samples prepared at 2 levels (200 and 400 mg/kg) with either a horizontal or vertical mixer. Along with the medicated feed samples were included 5 replicates of a blank control feed. The identities of the medicated and blank control feed samples were blinded to the analysts. The results for the medicated feed samples ranged from 95.8 to 106% of label claim, with a %CV ranging from 2.1 to 6.7%.

Thin-Layer Chromatographic Determination of Sterigmatocystin in Cheese: Interlaboratory Study

1987 ◽  
Vol 70 (5) ◽  
pp. 842-844
Author(s):  
Octave J Francis ◽  
George M Ware ◽  
Allen S Carman ◽  
Gary P Kirschenheuter ◽  
Shia S Kuan ◽  
...  
Keyword(s):  
Thin Layer ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
Interlaboratory Study ◽  
Thinlayer Chromatography ◽  
The Mean ◽  
Low Levels ◽  
Control Samples

Abstract A collaborative study of a method for the determination of sterigmatocystin in cheese was conducted by 10 laboratories. The study included control samples and samples spiked at levels of 5, 10, and 25 ppb, in coded blind pairs. Recoveries were 60.0, 90.7, and 59.3%, outliers excluded, for the respective levels. The mean reproducibilities, outliers excluded, were 81.97, 17.13, and 52.77%, respectively. Mean repeatabilities, outliers excluded, were 77.66,17.13, and 46.40%, respectively. Results of this collaborative study indicate that the method, modified as described in this report, is applicable to the determination of sterigmatocystin in cheese at low levels (5-50 ppb) for the purpose of surveys. With regard to the difficulty with thinlayer chromatography in this study, it is recommended that a more satisfactory determinative step be developed. Recommendation for official first action status is deferred

Simple Colorimetric Determination of Carrageenan in Jellies and Salad Dressings

1991 ◽  
Vol 74 (6) ◽  
pp. 1019-1022 ◽  
Author(s):  
Yoshie Yabe ◽  
Takahiro Ninomiya ◽  
Takashi Tatsuno ◽  
Taro Okada
Keyword(s):  
Gas Chromatography ◽  
Detection Limit ◽  
Alcian Blue ◽  
Coefficient Of Variation ◽  
Capillary Gas Chromatography ◽  
Colorimetric Method ◽  
Sample Solution ◽  
Colorimetric Determination ◽  
Chromatography Method

Abstract A simple, rapid colorimetric method is described for the determination of carrageenan (CAR) in foods such as jellies and salad dressings. Alcian blue reagent is added to the sample solution prepared from these foods, then CAR is precipitated selectively as a CAR-alcian blue complex. The precipitate is dissolved in monoethanolamine and determined colorimetrically at 615 nm. Overall recovery for jelly was 93.3% with a coefficient of variation (CV) of 5.8%. Overall recovery for salad dressing was 91.9% with a CV of 3.0%. The detection limit was 0.05%. The results obtained by the proposed method were similar to those obtained by a capillary gas chromatography method.

Gas Chromatographic Determination of Deoxynivalenol in Wheat with Electron Capture Detection: Collaborative Study

1986 ◽  
Vol 69 (5) ◽  
pp. 899-901 ◽  
Author(s):  
George M Ware ◽  
Octave J Francis ◽  
Allen S Carman ◽  
Shia S Kuan ◽  
◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Electron Capture ◽  
Collaborative Study ◽  
Control Sample ◽  
Chromatographic Determination ◽  
Electron Capture Detection ◽  
Average Recovery ◽  
Repeatability And Reproducibility ◽  
The Mean

Abstract Ten laboratories participated in a collaborative study of a method for the determination of deoxynivalenol in wheat by gas chromatography with electron capture detection. Each laboratory analyzed 6 samples in duplicate. Each collaborator received samples spiked at the 100.3, 501.3, and 1002.6 ng/g levels; a control sample; and 2 naturally contaminated samples. The average recovery (outliers excluded) for the spiked samples was 92.2%. The mean repeatability and reproducibility, respectively, were 32.2 and 41.3% for the spiked samples and 30.9 and 47.6% for the naturally contaminated samples. The method was adopted official first action.

Collaborative Study of a Fluorometric and Thin Layer Chromatographic Determination of Aminacrine and Its Salts in Drug Preparations

1967 ◽  
Vol 50 (3) ◽  
pp. 680-682
Author(s):  
Laura A Roberts
Keyword(s):  
Standard Deviation ◽  
Thin Layer ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
Assay Method ◽  
The Mean ◽  
Layer Chromatography ◽  
Mean Concentration

Abstract Eight collaborators studied a fluoromelric and thin layer chromatographic method for aminacrine and its salts in powder and cream drug preparations. Recovery of aminacrine.HCI by fluorometer in both preparations averaged 100% for powder and 102% for cream. The mean concentration of aminacrine.HCI found in the powder was 0.108% with a standard deviation of ± 0.001%. The mean concentration of aminacrine found in the cream was 0.191% with a standard deviation of ± 0.003%. Seven of the 8 collaborators successfully used thin layer chromatography to identify the aminacrine in both sample forms supplied. The assay method for aminacrine and its salts in drug preparations is recommended for adoption as official, first action

Capillary Gas Chromatographic Determination of Technical Chlordane in Emulsifiable Concentrates and Aqueous Dilutions

1985 ◽  
Vol 68 (2) ◽  
pp. 175-176
Author(s):  
Rodger W Stringham ◽  
Ray P Schulz
Keyword(s):  
Gas Chromatography ◽  
Capillary Gas Chromatography ◽  
Regression Coefficient ◽  
Chromatographic Determination ◽  
Electron Capture Detection ◽  
Average Recovery ◽  
Titrimetric Method ◽  
Relative Standard ◽  
Aoac Official

Abstract Technical chlordane is extracted in acetone, diluted with hexane, and determined via capillary gas chromatography with electron capture detection. Quantitation is based on the sum of areas or heights of 6 well resolved major peaks. The method was tested for precision, linearity, recovery, and applicability to aqueous dilutions of emulsifiable concentrate formulations. Comparison of quadruplicate analysis of 5 formulations by this method with the AOAC official titrimetric method gave average relative standard deviations of 1.4 and 0.9 %, respectively. Results were comparable for the 72% formulations, but were lower using this method for the 45% samples. Linearity and recovery were excellent (regression coefficient = 0.9996, recovery = 100.7%). Application of this method to aqueous dilutions was simple and resulted in an average recovery of 97%. The method is faster, safer, and more specific than the AOAC titrimetric method.

Gas Chromatographic Determination of Calcium Propionate Added as Preservative to Bread

1987 ◽  
Vol 70 (4) ◽  
pp. 763-767
Author(s):  
William M Lamkin ◽  
Natalie C Unruh ◽  
Yeshajahu Pomeranz
Keyword(s):  
Gas Chromatography ◽  
Phosphoric Acid ◽  
Coefficient Of Variation ◽  
Chromatographic Separation ◽  
Chromatographic Determination ◽  
Low Concentrations ◽  
Average Coefficient ◽  
Chromatographic Procedure ◽  
Calcium Propionate

Abstract A simple and rapid gas chromatographic procedure was developed for determining low concentrations of propionate added as a preservative to bread. A bread sample to be analyzed was ground in a meat grinder with a 3 mm hole plate and finely divided by rubbing through a No. 8 sieve. The propionate was then extracted into 0.050M formic acid in a blender at low speed for 5 min, and an aliquot of a filtrate was analyzed directly by gas chromatography. Chromatographic separation was accomplished on a Carbopack C column coated with 0.3% (w/w) Carbowax 20M and 0.1% (w/w) phosphoric acid. Less than 0.2 ppm propionic acid could be detected in the aqueous extract. Over the range of 0.03-0.23% calcium propionate, average relative error was —1.20% with an average coefficient of variation of 2.02%.

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