Quantitation of Polychlorinated Biphenyl Residues by Electron Capture Gas-Liquid Chromatography: Collaborative Study

1978 ◽  
Vol 61 (2) ◽  
pp. 282-291
Author(s):  
Leon D Sawyer
Keyword(s):  
Electron Capture ◽  
Polychlorinated Biphenyl ◽  
Collaborative Study ◽  
Peak Height ◽  
Gas Liquid Chromatography ◽  
Chicken Fat ◽  
Fortified Milk ◽  
Significant Difference ◽  
The Individual ◽  
Liquid Chromatographic

Abstract Ten collaborators quantitated 2 synthetically prepared polychlorinated biphenyl (PCB) mixtures, 2 PCB-fortified milk samples, and an incurred PCB residue in milk and chicken fat. Three electron capture gas-liquid chromatographic (GLC) methods were used for quantitating each unknown PCB against Aroclor reference materials. Two of the methods were existing AOAC total response comparisons and the third was a proposed individual peak comparison. In addition, existing AOAC multiresidue pesticide methodology was employed for determining PCB recovery from whole milk. The average combined recovery of Aroclor 1254 from milk fortified at 1.4 and 2.7 ppm (fat) was approximately 85% (coefficient of variation, 15%) with no significant difference by the methods of quantitation. The incurred PCB residue in milk (as 1254) was determined to be 1.3 (30%), 1.7 (31%), and 1.2 ppm (18%) by total peak height, total area, and individual peak quantitation methods, respectively. In the same order, incurred PCB in chicken fat was determined to be 6.8 (13%), 7.5 (16%), and 5.6 ppm (8%) as 1242, or 6.9 (6%), 5.9 (8%), and 6.3 ppm (8%) as 1248. Total PCB quantitated individually in a 3- and a 4-component chlorobiphenyl mixture, using 1248 as the reference standard, resulted in the following averages of actual amounts present: 3-component—109% (23%), 95% (18%), and 95% (6%); 4-component— 116% (16%), 112% (29%), and 104% (7%), respectively, for total peak height, total area, and individual peak quantitation methods. Both the individual peak quantitation method and the AOAC multi-pesticide methodology have been adopted as official first action methods for PCB.

Quantitation of Polychlorinated Biphenyl Residues by Electron Capture Gas-Liquid Chromatography: Reference Material Characterization and Preliminary Study

1978 ◽  
Vol 61 (2) ◽  
pp. 272-281
Author(s):  
Leon D Sawyer
Keyword(s):  
Electron Capture ◽  
Material Characterization ◽  
Chemical Ionization ◽  
Polychlorinated Biphenyl ◽  
Collaborative Study ◽  
Gas Liquid Chromatography ◽  
Ionization Mass ◽  
Preliminary Study ◽  
The Individual ◽  
Liquid Chromatographic

Abstract Weight per cent compositions of individual peaks of Aroclors 1016, 1242, 1248, 1254, and 1260 were determined under standard gas-liquid chromatographic (GLC) conditions. The GLC peak compositions were determined by using a Hall electrolytic conductivity detector for chlorine measurement and chemical ionization mass spectrometry with single ion monitoring for molecular weight characterization. The Aroclors used are available as reference materials for individual peak quantitation of polychlorinated biphenyl (PCB) residues by electron capture GLC. On the basis of a limited interlaboratory study and a collaborative study, the individual peak method shows improved interlaboratory precision and/or accuracy in PCB quantitation over existing methods.

Collaborative Study of the Recovery and Gas Chromatographic Quantitation of Polychlorinated Biphenyls in Chicken Fat and Polychlorinated Biphenyl–DDT Combinations in Fish

1973 ◽  
Vol 56 (4) ◽  
pp. 1015-1023 ◽  
Author(s):  
Leon D Sawyer
Keyword(s):  
Polychlorinated Biphenyls ◽  
Electron Capture ◽  
Silicic Acid ◽  
Polychlorinated Biphenyl ◽  
Collaborative Study ◽  
Peak Height ◽  
Chlorinated Pesticides ◽  
Chicken Fat ◽  
Fish Samples ◽  
Aroclor 1242

Abstract Nine laboratories collaborated on the analyses of PCBs in chicken fat and DDT-PCB combinations in fish. Existing AOAC multipesticide methodology with GLC quantitation was employed. One solution containing a mixture of Aroclors 1254 and 1260 was analyzed by GLC only. The fish samples were subjected to a published silicic acid procedure for separating the DDT-PCB mixtures. The DDT analogs were quantitated before and after the separation. The PCB content was quantitated by total peak height and total area comparisons against appropriate Aroclor(s), using electron capture GLC, and additionally in 6 laboratories by total area comparisons, using halogen-specific detection. The electron capture GLC data demonstrated better accuracy and precision. The following PCB recoveries were obtained by using total peak height comparisons: 5 ppm mixed Aroclor solution, 100±4%; 8 ppm Aroclor 1242-fortified chicken fat, 101±13%; 7.5 ppm Aroclor 1248-fortified chicken fat, 96±9%; incurred Aroclor 1242 chicken fat, 9.2 ppm±8%; 6 ppm Aroclor 1254-fortified fish, 75±14%; 6 ppm Aroclor 1260-fortified fish, 75±15%; and an environmentally incurred residue in fish, 4.5 ppm±20%. The 2 Aroclor-fortified fish samples were concurrently spiked with the p,p′-isomers of DDE, TDE, and DDT at levels of 4, 1, and 3 ppm, respectively. After silicic acid separation the combined recoveries for these 2 samples were: DDE, 86±13%; TDE, 89±20%; and DDT, 84±17%. Environmentally incurred-DDT residues were recovered at 4.1 ppm±14% for p,p′-DDE, 0.7 ppm±24% for o,p′-DDT, and 2.7 ppm±17% for p,p′-DDT. The DDT values calculated before the silicic acid separation compared favorably with those summarized. The multiresidue method for chlorinated pesticides, 29.001–29.027, has been adopted official first action to include polychlorinated biphenyls in poultry fat and fish.

Collaborative Study of the Gas-Liquid Chromatographic Determination of Coumarin (1,2-Benzopyrone) in Wine

1976 ◽  
Vol 59 (4) ◽  
pp. 780-782
Author(s):  
Randolph H Dyer ◽  
Glenn E Martin
Keyword(s):  
Collaborative Study ◽  
Chromatographic Determination ◽  
Chloroform Extract ◽  
Gas Liquid Chromatography ◽  
Individual Values ◽  
Significant Difference ◽  
Liquid Chromatographic Determination ◽  
The Individual ◽  
Liquid Chromatographic

Abstract The determination of coumarin in wine by using gas-liquid chromatography of a chloroform extract was collaboratively studied. Eleven collaborators analyzed 6 samples: 3 containing 4.0 mg coumarin/L, 2 containing 8.0, and 1 containing 0.0. When the triplicate and duplicate recoveries for the 4.0 and 8.0 levels were averaged and treated singly for the collaborators, there was no statistically significant difference in the accuracy between the 2 levels. However, the accuracy for the 4.0 level was much better than that for the 8.0 level: 100.0 vs. 105.9%. An analysis of the individual values showed no significant differences among collaborator means at the 4.0 level, while there was a significant difference among means at the 8.0 level. All collaborators were within the allowable score limits in the ranking test. The method was adopted as official first action.

scholarly journals Quantitative Calculation of Gas Chromatographic Peaks in Pesticide Residue Analyses

1966 ◽  
Vol 49 (2) ◽  
pp. 389-399
Author(s):  
Jean A Gaul
Keyword(s):  
Electron Capture ◽  
Peak Height ◽  
Electron Capture Detection ◽  
Gas Liquid Chromatography ◽  
Gas Chromatograph ◽  
Quantitative Calculation ◽  
Parallel Lines ◽  
Half Height ◽  
Significant Difference ◽  
Chromatographic Peaks

Abstract Comparison of five methods for calculating gas chromatographic peaks (disc integration, triangulation, peak height × width at half height, Rt × peak height, and peak height) shows no significant difference in the calculated results when aldrin, heptachlor epoxide, and dieldrin are injected into a gas chromatograph equipped with electron capture detector. Problems are associated with the calculation of toxaphene, chlordane, DDT, and BHC The author makes suggestions for calculating these four residues when present individually and in combinations with other pesticides. Use of the last fovir toxaphene peaks compares favorably with results obtained by vising the entire toxaphene curve. A method for calculating DDT in the presence of toxaphene, based on the construction of “parallel lines”, gives 89–100% of the DDT in the presence of 1–10 parts of toxaphene. Results for chlordane obtained by adding heights of individual chlordane peaks are shown to be close to results obtained with an integrator. When electron capture detection is used for determining the α, β, γ, and δ-isomers of BHC, the response of the β-isomer is fovmd to be approximately 50% less than response of the other isomers, thus pointing up the need for use of individual BHC isomers for electron capture gas-liquid chromatography quantitation.

Electron capture gas-liquid chromatographic-mass spectral identification of acids produced by Neisseria meningitidis in a defined medium

1979 ◽  
Vol 9 (1) ◽  
pp. 97-102
Author(s):  
C C Alley ◽  
J B Brooks ◽  
D S Kellogg
Keyword(s):  
Liquid Chromatography ◽  
Neisseria Meningitidis ◽  
Electron Capture ◽  
Defined Medium ◽  
Gas Liquid Chromatography ◽  
Mass Spectral ◽  
Spectral Identification ◽  
Acid Metabolites ◽  
Liquid Chromatographic ◽  
Chromatographic Mass

The acid metabolites and the cellular fatty acids of three strains of Neisseria meningitidis grown in a chemically defined liquid medium were determined with computerized frequency-pulsed electron capture gas-liquid chromatography. Five acids not previously reported were subsequently identified: isobutyric, octanoic, decenoic (C10:1), dodecenoic (C12:1), and tetradecenoic (C14:1). These acids were produced during active metabolism and were not detected as cellular constituents. The frequency-pulsed electron capture gas-liquid chromatography methods which we used provide a rapid, reliable, sensitive means of detecting both these and other metabolic and cellular acids in spent culture medium.

High Pressure Liquid Chromatographic Determination of Fensulfothion: Collaborative Study

1983 ◽  
Vol 66 (3) ◽  
pp. 801-803
Author(s):  
Margie E Owen ◽  
◽  
O O Bennett ◽  
L T Chenery ◽  
C J Cohen ◽  
...  
Keyword(s):  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Peak Height ◽  
Matched Pair ◽  
Standard Material ◽  
Liquid Chromatographic Determination ◽  
The Difference ◽  
Liquid Chromatographic

Abstract A method for analyzing fensulfothion was tested by 10 collaborators. Formulations were dissolved, or extracted from inerts, in methanol. Benzophenone was used as an internal standard. The solution was diromatographed on a Partisil-10 ODS-2, or equivalent, reverse phase column, and detected at 230 nm. A mobile phase of methanol-water-phosphoric acid was used. The ratio of fensulfothion peak height to benzophenone peak height was calculated from the UV response and compared to the standard material for quantitation. A 15% granular formulation was analyzed as a matched pair. The results of one collaborator were outliers by the Dixon test. The coefficient of variation for the granular formulation was 1.6%. A matched pair of 63% spray concentrate samples was analyzed by 10 collaborators. The difference in results was an outlier for one collaborator; the coefficient of variation for the other collaborators was 1.5%. The method has been adopted official first action.

Liquid Chromatographic Determination of Diclazuril in Premix and Supplemented Feed: Interlaboratory Study

1994 ◽  
Vol 77 (6) ◽  
pp. 1359-1361 ◽  
Author(s):  
Andre Fontaine ◽  
Karel Haustraete
Keyword(s):  
Solid Phase ◽  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Peak Height ◽  
Reversed Phase ◽  
Poultry Feed ◽  
Uv Detector ◽  
Relative Standard ◽  
Liquid Chromatographic

Abstract Diclazuril, Janssen Research Compound R 64433 (Clinacox), is analyzed by liquid chromatography (LC). Compound R 062646, with a structure analogous to that of diclazuril, is used as internal standard. The drug is extracted from feed with acidified methanol. Diclazuril is then isolated by solid-phase extraction (SPE) with a cartridge containing a C18 phase. The eluate is evaporated, and the residue is redissolved in dimethylformamide. An aliquot is injected onto a reversed-phase ODS LC column, and the drug quantitated at 280 nm with a UV detector. Peak areas are obtained at the retention times corresponding to the internal standard and diclazuril. The quantity of active ingredient is determined by comparing the ratio of the peak height of diclazuril to that of internal standard in the sample with the same ratio in a single calibration solution. SPE is not necessary for the analysis of premixes. Eleven laboratories participated in the collaborative study. Laboratories were provided with 2 samples of premixes and 3 samples of feed for poultry. Feed sample K1 was sent to only 6 laboratories. The reproducibility relative standard deviations (RSDRS) were 7.38 and 7.53% for the 2 premixes and 9.67,13.65, and 18.61% for the 3 samples of supplemented feed.

Measurement of thiamylal and thiopental in plasma by electron capture and flame photometric gas-liquid chromatography.

1977 ◽  
Vol 23 (7) ◽  
pp. 1306-1309 ◽  
Author(s):  
R H Smith ◽  
J A MacDonald ◽  
D S Thompson ◽  
W E Flacke
Keyword(s):  
Liquid Chromatography ◽  
Ethyl Acetate ◽  
Electron Capture ◽  
Internal Standard ◽  
Chromatographic Column ◽  
Gas Liquid Chromatography ◽  
Unchanged Drug ◽  
Chromatographic Procedure ◽  
Isothermal Gas ◽  
Liquid Chromatographic

Abstract We describe an isothermal gas-liquid chromatographic procedure developed for measuring thiamylal and thiopental in plasma. The unchanged drug is extracted into ethyl acetate from acidified plasma, together with an internal standard. The solvent is removed, the residue methylated, aliquots, diluted with benzene, are injected into a 183-cm gas-liquid chromatographic column containing 3% OV-17. Sensitivity of detection is in the nanogram to picogram range.

Modification of the AOAC Gas-Liquid Chromatographic Method for Indole in Shrimp: Collaborative Study

1982 ◽  
Vol 65 (4) ◽  
pp. 842-845
Author(s):  
Theodore L Chambers ◽  
◽  
E C Netz ◽  
K Ogger
Keyword(s):  
Silica Gel ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Internal Standard ◽  
Current Method ◽  
Peak Height ◽  
Modified Method ◽  
Liquid Chromatographic Method ◽  
Gas Chromatographic Method ◽  
Liquid Chromatographic

Abstract Several changes were suggested for standardization of the AOAC official final action gas chromatographic method for the determination of indole in shrimp. In a collaborative study, 3 FDA laboratories compared the modified method with the current method. At a 95% confidence level, the same results were obtained for each respective sample by the AOAC or the modified method, which had the following changes. The cleanup column was standardized by drying the silica gel for 2 h at 125°C and equilibrating with 3 g of water/25 g of silica gel. Concentrated ethyl acetate shrimp extracts were treated with anhydrous sodium sulfate before column cleanup and indole was eluted from the column with 15% ethyl ether/hexane. A reduced amount of the internal standard, 2-methylindole, was used to improve peak height measurements at the 25 μg% indole level. The modified method has been adopted official first action to replace method 18.075.

Liquid-chromatographic measurement of p-aminobenzoic acid and its metabolites in serum.

1988 ◽  
Vol 34 (11) ◽  
pp. 2235-2238 ◽  
Author(s):  
L L Yung-Jato ◽  
P R Durie ◽  
S J Soldin
Keyword(s):  
High Performance ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Peak Height ◽  
Individual Compound ◽  
Aminobenzoic Acid ◽  
Serum Samples ◽  
The Individual ◽  
A Minor ◽  
Liquid Chromatographic

Abstract This is a high-performance liquid-chromatographic method for measuring p-aminobenzoic acid (PABA) and its metabolites in plasma or serum. Samples are deproteinized, then extracted with organic solvents before chromatography. For quantification, the peak height of the individual compound is compared with that of the internal standard. Analytical recoveries ranged from 41% to 100%, depending on the compound studied. Comparison of patients' samples after oral administration of either N-benzoyl-L-tyrosyl-p-aminobenzoic acid or free PABA revealed that PABA is extensively metabolized and conjugated to either p-acetamidobenzoic acid, p-aminohippuric acid, or p-acetamidohippuric acid. PABA concentrations in serum as measured with the Bratton-Marshall ultraviolet spectrophotometric procedure would appear predominantly to reflect measurements of metabolites, with only a minor contribution from PABA itself.

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