Electron-capture gas-liquid chromatographic determination of ethosuximide and desmethylmethsuximide in plasma or serum.

1979 ◽  
Vol 25 (2) ◽  
pp. 252-255 ◽  
Author(s):  
J E Wallace ◽  
H A Schwertner ◽  
H E Hamilton ◽  
E L Shimek
Keyword(s):  
Electron Capture ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Salting Out ◽  
Liquid Chromatograph ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Derivatives Of

Abstract We describe the determination of ethosuximide and desmethylmethsuximide, simultaneously or separately, in 50 to 100 microliter of plasma or serum. Derivatives of ethosuximide and desmethylmethsuximide formed by reaction with pentafluorobenzoyl chloride are extremely sensitive to the electron-capture detector of a gas-liquid chromatograph. The sample, with added internal standard and ammonium sulfate as a pH-adjusting and salting-out agent, is extracted with ethyl acetate/benzene (20/80 by vol). The extract is evaporated and the derivatives are formed. Analytical recoveries of ethosuximide and desmethylmethsuximide exceed 99%, and the relative standard deviation (CV) between analyses is usually less than 4.0%. alpha-Methyl-alpha-propylsuccinimide is used as the internal standard for ethosuximide, 2-phenylsuccinimide as the internal standard for desmethylmethsuximide.

Liquid Chromatographic Determination of Bendiocarb in Technical Materials and Wettable Powder Formulations: Collaborative Study

1986 ◽  
Vol 69 (5) ◽  
pp. 908-911
Author(s):  
Peter L Carter ◽  
Keith C Overton ◽  
◽  
P G Baker ◽  
O O Bennett ◽  
...  
Keyword(s):  
Statistical Data ◽  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Liquid Chromatograph ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method for determination of bendiocarb in technical materials and wettable powders was tested by 12 collaborators. Bendiocarb is dissolved in acetonitrile containing 0.1% propiophenone as internal standard. This solution is analyzed on a liquid chromatograph utilizing a reverse phase (C18) column. The compound is detected at 254 nm and peak area is used for quantitation. The 3 different materials studied contained 20, 80, and nominally 100% bendiocarb. Each was examined in duplicate to provide the necessary matched pairs. Collaborators approved of the ease and simplicity of the method and, in particular, the way the method can be applied to automatic injection assemblies. The statistical data show acceptable precision of the method: Reproducibility coefficients of variation were 20% material, 2.04%; 80% material, 1.02%; and nominal 100% material (technical product), 0.64%. The method has been adopted official first action.

A Simplified Method for the Gas-Liquid Chromatographic Determination of Methyl Mercury in Fish and Shellfish

1976 ◽  
Vol 59 (6) ◽  
pp. 1226-1233 ◽  
Author(s):  
James O Watts ◽  
Kenneth W Boyer ◽  
Anthony Cortez ◽  
Edgar R Elkins
Keyword(s):  
Methyl Mercury ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Mercury Chloride ◽  
Liquid Chromatograph ◽  
Mercury In Fish ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Fish And Shellfish

Abstract A simple acetone wash of the fish sample which removes lipids and other organic materials replaces the cysteine cleanup specified in other methods. Methyl mercury is freed by hydrochloric acid, extracted into benzene, and determined with a gas-liquid chromatograph equipped with an electron capture detector. The method is quantitative for methyl mercury levels as low as 0.10 ppm in fish and shellfish. Ethyl mercury chloride may be used as an internal standard to detect unsuspected error or instrumental parameter variation.

Gas-Liquid Chromatographic Determination of Fluchloralin in Formulations

1977 ◽  
Vol 60 (5) ◽  
pp. 1145-1147
Author(s):  
Gregory S Grimes
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Reference Standard ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Standard Solution ◽  
Liquid Chromatographic

Abstract A gas-liquid chromatographic (GLC) method has been developed that is precise, rapid, simple, and specific for fluchloralin in emulsifiable liquid formulation. Sample and reference standard are weighed, internal standard solution is added, and an aliquot of the mixture is injected onto the chromatographic column. Fluchloralin gives a sharp symmetrical peak at about 5.4 min. The internal standard has a broader symmetrical peak at about 6.9 min. The relative standard deviation for 21 consecutive injections of the standard solution was 0.3773%. The method was compared with the official GLC method, 6.210–6.215, for the structurally similar trifluralin. Fluchloralin gave a sharp symmetrical peak at about 8.5 min; the internal standard had a sharp symmetrical peak at about 9.2 min. The relative standard deviation of 21 consecutive injections of reference standard solution was 0.6988%. Comparison of the variances of the 2 methods by the F-test at the 99% confidence level showed that the proposed method demonstrated substantially better precision.

Gas-Liquid Chromatographic Determination of Aniline Metabolites of Substituted Urea and Carbamate Herbicides in Aqueous Solution

1981 ◽  
Vol 64 (4) ◽  
pp. 833-840
Author(s):  
Erika E Hargesheimer ◽  
Ronald T Coutts ◽  
Franco M Pasutto
Keyword(s):  
Aqueous Solution ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Distilled Water ◽  
Substituted Anilines ◽  
Flame Ionization ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Derivatives Of

Abstract A simple gas-liquid chromatographic (GLC) method has been developed which provides sensitivity and specificity for the analysis of complex mixtures of the commonly occurring herbicide metabolites aniline, 3-chloroaniline, 4-chloroaniline, 4-bromoaniline, and 3-chloro-4-methylaniline. All of these anilines react with acetic anhydride directly in basified aqueous solution. Further reaction of the acetylated anilines with trifluoroacetic anhydride gave diacyl derivatives which were readily resolved by gas chromatography. The structures of the N-acetylated and IV-trifluoroacetylated derivatives of benzylamine (internal standard) and the anilines were confirmed by GLC-mass spectrometry. In distilled water the minimum detectable concentrations of aniline and the substituted anilines, using electron capture GLC, are 0.1 nmole/100 mL and 0.05 nmole/100 mL, respectively. The detection limit for the anilines is 1 nmole/100 ml distilled water, using GLC with flame ionization detection. The technique was applied to the determination of anilines added to urine samples obtained from the general population.

Liquid Chromatographic Determination of Fluorescent Derivatives of Six Sulfonamides in Bovine Serum and Milk

1995 ◽  
Vol 78 (3) ◽  
pp. 674-678 ◽  
Author(s):  
Chin-En Tsai ◽  
Fusao Kondo
Keyword(s):  
Bovine Serum ◽  
Potassium Phosphate ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Fluorometric Detection ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Derivatives Of ◽  
Fluorescent Derivatives

Abstract A rapid and sensitive liquid chromatographic (LC) method with fluorometric detection was developed to detect sulfadiazine, sulfathiazole, sulfamethazine, sulfamonomethoxine, sulfamethoxazole, and sulfadimethoxine residues in bovine serum and milk. p-Aminobenzoic acid (PABA) was added as an internal standard. The sulfonamides were extracted from samples and derivatized with fluorescamine, and 50 μL was injected into a NovaPak C18 LC column and eluted with acetonitrile– 10 mM potassium phosphate (30 + 70, v/v). The sulfonamides were detected fluorometrically (excitation, 390 nm; emission, 475 nm), and their retention times ranged from 6.2 to 16.5 min without interference from coextractives. The detection limit for standard sulfonamide solution was 0.1 ng/mL; the calibration curves were linear between 1 and 100 ng/mL in the presence of PABA as internal standard. Recovery rates of sulfonamides from spiked samples (1 and 10 ppb) were 95.4–107.2 and 81.4–89.6% for serum and 80.7–91.1 and 62.6–84.1% for milk, respectively.

High Pressure Liquid Chromatographic Determination of Chlorophacinone in Formulations

1979 ◽  
Vol 62 (5) ◽  
pp. 1001-1003
Author(s):  
Ralph G Grant ◽  
Richard K Pike
Keyword(s):  
High Pressure ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Whole Grain ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatograph ◽  
High Pressure Liquid Chromatograph ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A simple and rapid method is described determining for 2- ((p-chlorophenyl) phenylacetyl-1,3- indandione (chlorophacinone) in rodenticides formulated as tracking powders and whole grain and crushed grain baits. The bait is extracted with methanol containing an internal standard, and the extract is injected into a high pressure liquid chromatograph. The sample is analyzed by reverse phase chromatography on octadecyl (C18) bonded to glass beads with a mobile phase of methanolwater (35+65) plus 0.75% NH4OH. A 5 μL injection containing 240 ng benzophenone internal standard and 77 ng chlorophacinone produces half scale peaks at 280 nm with a full scale absorbance of 0.01 absorbance unit. Two formulations and a spiked sample were analyzed by the method. Recovery as determined by peak area was >97%.

High Pressure Liquid Chromatographic Determination of N-3-Pyridylmethyl-N′-p-nitrophenylurea in Rodenticides

1977 ◽  
Vol 60 (6) ◽  
pp. 1375-1378
Author(s):  
Carl W Sims ◽  
Richard K Gard
Keyword(s):  
High Pressure ◽  
Methylene Chloride ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Liquid Chromatograph ◽  
Two Samples ◽  
High Pressure Liquid Chromatograph ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A simple and rapid method is described for determining N′-3-pyridylmethyl-N′-p-nitrophenylurea (RH-787) in Vacor Ratkiller rodenticide. The bait is extracted with acetone, the extract is evaporated to dryness, an internal standard is added, and the solution is injected into a high pressure liquid chromatograph. The sample is analyzed by normal phase chromatography on a Partisil 10 column with a mobile phase of methanol-methylene chloride (10+90). An 8 μl injection containing 4 μg pyridine internal standard and 8 μg RH-787 produces half-scale peaks at 254 nm with a full scale absorbance of 0.5 absorbance unit. In an alternative procedure, the active ingredient is extracted from the bait with acetone and titrated to a methyl red end point with 0.1N perchloric acid dissolved in acetic acid. Two samples of Vacor Ratkiller and a spiked blank were analyzed by both procedures.

Gas-Liquid Chromatographic Determination of Ethopabate in Feed Premixes

1978 ◽  
Vol 61 (3) ◽  
pp. 561-563
Author(s):  
Robert L Smallidge
Keyword(s):  
Internal Standard ◽  
Chromatographic Determination ◽  
Gas Chromatograph ◽  
Ionization Detector ◽  
Flame Ionization ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A gas-liquid chromatographic method is presented for determining ethopabate in 0.8 and 8.0% premixes. A sample is extracted with tetrahydrofuran containing an internal standard, by sonication or overnight soaking. The extract is clarified by centrifugation, diluted if necessary, and injected into a gas chromatograph equipped with a flame ionization detector. Average per cent recoveries for spiked blank samples were 100.6 at the 0.8% level and 100.4 at the 8.0% level. Precision, as indicated by replicate analyses of several premixes, ranged from 0.5 to 1.7% relative standard deviation

scholarly journals High-performance liquid chromatographic determination of famotidine in human plasma using solid-phase column extraction

2003 ◽  
Vol 68 (11) ◽  
pp. 883-892 ◽  
Author(s):  
Dragica Zendelovska ◽  
Trajce Stafilov
Keyword(s):  
Human Plasma ◽  
High Performance ◽  
Solid Phase ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Water Ph ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

A rapid, specific and sensitive high-performance liquid chromatographic method for the determination of famotidine in human plasma has been developed. Famotidine and the internal standard were chromatographically separated from plasma components using a Lichrocart Lichrospher 60 RP select B cartridge for solid-phase separation with a mobile phase composed of 0.1 % (v/v) triethylamine in water (pH 3) and acetonitrile (92:8, v/v). UV detection was set at 270 nm. The calibration curve was linear in the concentration range of 10.0 ? 350.0 ng mL-1. The method was implemented to monitor the famotidine levels in patient samples.

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