Evaluation of Liquid Chromatographic Methods for Analysis of Chlorphoxim Formulations

1985 ◽  
Vol 68 (5) ◽  
pp. 887-890
Author(s):  
Dwight L Mount ◽  
James W Miles
Keyword(s):  
Ethyl Acetate ◽  
Disease Control ◽  
Silica Gel ◽  
Active Ingredient ◽  
Internal Standard ◽  
Emulsifiable Concentrate ◽  
Water Dispersible ◽  
External Standard ◽  
Liquid Chromatographic

Abstract Liquid chromatographic (LC) methods for determination of active ingredient in chlorphoxim formulations have been developed independently by Bayer AG and the Centers for Disease Control (CDC). Both methods specify separation on a silica gel column. The Bayer method uses a 5% solution of tetrahydrofuran in hexane as the eluting solvent and quantitates results on the basis of an external standard. The CDC method uses a 5% solution of ethyl acetate in hexane as the eluting solvent and uses 4-fluorophenyl sulfone as an internal standard. The 2 methods were compared by replicate analyses of samples of chlorphoxim technical and water-dispersible powder and emulsifiable concentrate formulations. The precision of both methods was acceptable

High Performance Liquid Chromatographic Method for Determination of Temephos in Technical and Formulated Products: Collaborative Study

1982 ◽  
Vol 65 (3) ◽  
pp. 580-583
Author(s):  
James W Miles ◽  
Dwight L Mount
Keyword(s):  
Ethyl Acetate ◽  
High Performance ◽  
Collaborative Study ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Hplc Method ◽  
Water Dispersible ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic

Abstract An HPLC method for the determination of temephos in temephos technical and formulated products has been subjected to an international collaborative study with 14 laboratories participating. Samples were extracted with ethyl acetate and eluted on a silica gel column with ethyl acetate-hexane (1 + 9); p-nitrophenyl p-nitrobenzoate served as the internal standard. Collaborators were furnished samples of technical, 20 and 50% emulsifiable concentrates, 50% water-dispersible powder, and 1% sand granules. The coefficients of variation of the values obtained on the 5 samples were 1.21,2.02,1.26,1.89, and 9.90%, respectively. The method has been adopted official first action.

Gas Chromatographic Methods for Determination of γ-BHC in Technical Emulsifiable Concentrates and Water-Dispersible Powder Formulations and in Lindane Shampoo and Lotion: Collaborative Study

1984 ◽  
Vol 67 (4) ◽  
pp. 834-837
Author(s):  
James W Miles ◽  
Dwight L Mount ◽  
◽  
T J Beckmann ◽  
S K Carrigan ◽  
...  
Keyword(s):  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Internal Standard ◽  
The Other ◽  
Water Dispersible ◽  
Coefficients Of Variation ◽  
Aoac Method ◽  
Liquid Chromatographic ◽  
Gas Chromatographic Separation

Abstract Although the gas chromatographic separation of the isomers of BHC was demonstrated two decades ago, the present AOAC method of analysis of BHC for gamma-isomer (lindane) content is based on a separation carried out on a liquid chromatographic partition column. A method of analysis has been developed that uses an OV-210 column for separation of the gamma-isomer from the other isomers and impurities in technical BHC. Di-n-propyl phthalate was chosen as an internal standard. The same system allows quantitation of lindane in lotion and shampoo after these products are extracted with ethyl acetate-isooctane (1 + 4). The analytical methods were subjected to a collaborative trial with 10 laboratories. The coefficient of variation for technical BHC was 2.83%. For the water-dispersible powder and emulsifiable concentrate, the coefficients of variation were 2.89% and 4.62%, respectively. Coefficients of variation for 1% lindane lotion and shampoo were 4.36% and 11.92%, respectively. The method has been adopted official first action.

Gas-Liquid Chromatographic Determination of Captan and Two Metabolites in Milk and Meat

1977 ◽  
Vol 60 (3) ◽  
pp. 679-681
Author(s):  
John H Onley
Keyword(s):  
Ethyl Acetate ◽  
Silica Gel ◽  
Chromatographic Determination ◽  
Gel Chromatography ◽  
Milk Samples ◽  
Liquid Chromatographic Determination ◽  
Meat Samples ◽  
Silica Gel Chromatography ◽  
Liquid Chromatographic

Abstract A gas-liquid chromatographic (GLC) method has been developed for the determination of captan (N-trichloromethylthio-4-cyclohexene-1, 2-dicarboximide) and 2 metabolites, tetrahydrophthalimide (THPI) and tetrahydrophthalamic acid (THPMA), in milk and meat. The sample is extracted with ethyl acetate and is cleaned up by acetonitrile partition and silica gel chromatography where captan, THPI, and THPMA are separated. Captan is directly determined by GLC. THPI and THPMA are separately derivatized in an acetone solution of penta fluorobenzyl bromide. The resultant derivatives are purified separately on an Al2O3, column and quantitated by GLC, using an electron capture detector. Recoveries from milk samples fortified at 0.02–10 ppm ranged from 71 to 102%; recoveries from meat samples fortified at 0.04–10 ppm ranged from 75 to 99%.

Gas Chromatographic Determination of Metolachlor in Pesticide Formulations: Collaborative Study

1985 ◽  
Vol 68 (3) ◽  
pp. 570-572
Author(s):  
Thomas G Gale ◽  
Arthur H Hofberg
Keyword(s):  
Active Ingredient ◽  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Matched Pair ◽  
Emulsifiable Concentrate ◽  
Flame Ionization ◽  
Pesticide Formulations ◽  
Better Than

Abstract A gas chromatographic (GC) procedure for the determination of metolachlor in emulsifiable concentrate formulations containing about 76% active ingredient was collaboratively studied using the matched pair scheme. Metolachlor was extracted from the formulation with acetone containing dipentyl phthalate as the internal standard, chromatographed on OV-101, and detected by flame ionization. Determinations on the 4 samples by 21 government, university, and industrial collaborators using peak area measurements showed within-laboratory repeatability of better than 0.5%. Reproducibility was better than 1% for the formulation. The method has been adopted official first action.

Multiple Internal Standard Technique for the Gas-Liquid Chromatographic Determination of Indole in Shrimp

1978 ◽  
Vol 61 (1) ◽  
pp. 136-138
Author(s):  
Walter F Staruszkiewicz ◽  
John F Bond
Keyword(s):  
Silica Gel ◽  
Room Temperature ◽  
Internal Standard ◽  
Standard Technique ◽  
Chromatographic Determination ◽  
Experimental Conditions ◽  
Liquid Chromatographic Determination ◽  
Standard Solution ◽  
Liquid Chromatographic

Abstract A multiple internal standard technique has been developed for the official first action gas-liquid chromatographic (GLC) method for determining indole in shrimp. The modification was developed because interfering GLC peaks are occasionally observed when 2-methylindole is used as the internal standard. An internal standard solution containing 1-methylindole, 2- methylindole, and diphenylamine was added to extracts of shrimp before silica gel cleanup and separation by GLC. All of the compounds were quantitatively recovered and were separated on the GLC column under identical experimental conditions. Extracts of acceptable shrimp to which indole was added at levels of 3–10 μg/ 100 g and extracts of decomposed shrimp were stored at room temperature for 2 weeks. Average and maximum changes (μg indole/100 g) during storage were, respectively, for each internal standard: average 0.6, 0.4, and 1.1; maximum 1.7, 0.9, and 2.9.

Gas-Liquid Chromatographic Determination of Adipate Content of Acetylated Di-starch Adipate

1982 ◽  
Vol 65 (2) ◽  
pp. 238-240
Author(s):  
Gordon A Mitchell ◽  
Michel J Vanderbist ◽  
Florent F Meert
Keyword(s):  
Ethyl Acetate ◽  
Adipic Acid ◽  
Silicone Oil ◽  
Internal Standard ◽  
Active Phase ◽  
Chromatographic Determination ◽  
Silyl Derivative ◽  
Alkaline Conditions ◽  
Liquid Chromatographic

Abstract A gas-liquid chromatographic method is described for rapid, quantitative determination of adipate content of acetylated di-starch adipate. The adipate group is very labile and, under mild alkaline conditions at ambient temperature, is easily hydrolyzed from the starch. Free adipic acid is formed by acidification of the solution with HC1, and then extracted with ethyl acetate. Ethyl acetate is removed under vacuum distillation, and a silyl derivative of the adipic acid is formed. Glutaric acid internal standard is introduced into the original starch sample before hydrolysis. An aliquot of the silylated solution is injected into a gas chromatograph fitted with a column having silicone oil as the active phase. A flame ionization detector is also incorporated. Results correlate well with the amount of adipylating reagent used. No adipic acid is detectable when a hydrolyzed, extracted sample of acetylated di-starch adipate is subjected to a second extraction. Recovery levels of adipic acid, from starches fortified with 100-500 ppm, are in the range of 97-102.5.%

Gas-Liquid Chromatographic Determination of Hexestrol Residues in Adipose Tissue

1981 ◽  
Vol 64 (3) ◽  
pp. 709-713
Author(s):  
Hisaya Tobioka ◽  
Ryoji Kawashima
Keyword(s):  
Adipose Tissue ◽  
Silica Gel ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Optimum Ratio ◽  
Extraction And Purification ◽  
Percent Recovery ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A gas-liquid chromatographic (GLC) method is described for determining hexestrol residues in adipose tissue. The extraction and purification procedures were based on a published method for determining diethylstilbestrol. To increase precision and sensi-(ivy, the sample was further cleaned up by silica gel column chromatography. The heptafluorobutyric (HFB) derivative of hexestrol was used for GLC analysis with HFB-docosanol as an internal standard. A variety of acetone-benzene mixtures were compared to determine the optimum ratio for hexestrol acylation. Acetone-benzene (90 + 10) or 100% acetone provided 16% higher GLC response than did a 50 – 50 mixture (P <0.001) and was selected for use in the acylation procedure. A system for evaporating excess reagents was also studied. Overall percent recovery reached 72 ± 5. The method can be used to determine residual hexestrol at the 0.1 ppb level.

Liquid-chromatographic measurement of creatinine in serum and urine.

1983 ◽  
Vol 29 (5) ◽  
pp. 851-853 ◽  
Author(s):  
T Okuda ◽  
T Oie ◽  
M Nishida
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Liquid Chromatographic Method ◽  
External Standard ◽  
Chromatographic Measurement ◽  
Liquid Chromatographic ◽  
Serum And Urine

Abstract We describe the adaptation of a "high-performance" liquid chromatographic method for determination of creatinine in serum and urine. The proposed method is simple, rapid, precise, and accurate. The retention time for creatinine can be varied simply by changing the KH2PO4 concentration in the mobile phase: acetonitrile/aqueous KH2PO4 (1/4 by vol). Within-day precision (CV) was 1.2-3.6% in serum chromatographed with an internal standard, and 2.3-2.8% in serum when an external standard was used. Between-day precision (CV) was 1.3-2.1% in serum and 1.3-2.7% in urine (with an external standard). Analytical recoveries of creatinine added to serum were 94-100% for the method with an internal standard, 95-103% with an external standard.

Gas-Liquid Chromatographic Determination of Residues of Oxadiazon and Its Metabolites in Green and Dry Hops and Hop Foliage

1982 ◽  
Vol 65 (1) ◽  
pp. 28-31
Author(s):  
Donald A George
Keyword(s):  
Liquid Chromatography ◽  
Active Ingredient ◽  
Chromatographic Determination ◽  
Late Spring ◽  
Gas Liquid Chromatography ◽  
Emulsifiable Concentrate ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Column Chromatographic

Abstract Ronstar EC (emulsifiable concentrate) was applied at rates of 4.48 or 8.96 kg ai/ha as a broadcast spray during the winter, in late spring, and in mid-summer to plots in commercial hop fields. Residues of oxadiazon, the active ingredient, and its 4 metabolites (methoxy, alcohol, acid, and phenol) were determined at harvest (1 month after last treatment) in green and dry hops and in hop foliage, by using gas-liquid chromatography after column chromatographic cleanup. Drying the cone increased residues of oxadiazon, but resulted in loss of the methoxy and alcohol metabolites. Oxadiazon residues in hop foliage ranged from 0.058 to 0.163 ppm. Measurable amounts of metabolites were also found in the foliage.

Gas Chromatographic Determination of Fluazifop-butyl in Formulations: Collaborative Study

1984 ◽  
Vol 67 (3) ◽  
pp. 499-502
Author(s):  
Peter D Bland ◽  
◽  
L Chenery ◽  
N Ellis ◽  
L Firestone ◽  
...  
Keyword(s):  
Active Ingredient ◽  
Methylene Chloride ◽  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Peak Height ◽  
Emulsifiable Concentrate ◽  
Coefficients Of Variation ◽  
Peak Areas

Abstract A method is described for the determination of butyl 2-(4-(5-trifluoromethyl- 2-pyridinyloxy)phenoxy) propanoate in technical and formulated material by gas chromatography (GC). Samples of technical or formulated material are dissolved in methylene chloride containing dibenzyl succinate as internal standard. The solution is injected into a gas chromatograph fitted with a flame ionization detector and a 6 ft × 2 mm glass column. The column is packed with 3% OV-17 on 100–120 mesh Chromosorb WHP and is maintained at 230°C. Peak areas obtained at the retention times of the internal standard and the active ingredient are measured with an integrator. The quantity of fluazifop-butyl is determined by comparing the internal standard and active ingredient peak areas with the peak areas obtained from a calibration solution containing known amounts of internal standard and pure active ingredient. Four samples were chosen for collaboration: technical fluazifop-butyl, a 4 lb/US gal. emulsifiable concentrate, a 560 g/L oil concentrate, and a 5% granular. Fourteen collaborators carried out replicate determinations on each sample. Coefficients of variation between laboratories were 0.80 for the technical, 0.88 for the emulsifiable concentrate, 1.03 for the oil concentrate, and 2.04 for the granular. Parallel peak height determinations showed substantially higher coefficients of variation for all except the granular sample. The method has been adopted official first action.

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