Determination of the activity coefficients of methanol and ethanol in benzene solutions by gas chromatography

1967 ◽  
Vol 45 (24) ◽  
pp. 3089-3095 ◽  
Author(s):  
Peter Pollak ◽  
G. C. B Cave
Keyword(s):  
Gas Chromatography ◽  
Quantitative Analysis ◽  
Activity Coefficients ◽  
Vapor Phase ◽  
Chromatographic Method ◽  
Low Concentrations ◽  
Gas Chromatographic Method

A rapid gas-chromatographic method is described for the quantitative analysis of the equilibrium vapor phase over a solution. A vapor pump has been designed for the purpose and is described. The method should be particularly useful at low concentrations of volatile solutes, alone or in mixtures. As an example of the application of the method, the vapor concentrations of methanol and of ethanol over benzene solutions at 25 °C have been measured. The precision of the data is also reported. The activity coefficients of the alcohols in the benzene solutions were calculated.

Gas Chromatographic Determination of N-Butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine and α,α,α-Trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine in Formulations

1971 ◽  
Vol 54 (3) ◽  
pp. 711-712
Author(s):  
Martha Fuzesi
Keyword(s):  
Gas Chromatography ◽  
Quantitative Determination ◽  
Electron Capture ◽  
Chromatographic Method ◽  
Chromatographic Determination ◽  
Electron Capture Detector ◽  
Reference Solution ◽  
Gas Chromatographic Method

Abstract A gas chromatographic method is described for the quantitative determination of N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-tolindine and α,α,α-trifluoro-2,6-dinitro-N,N-dipropyI-p-toluidine herbicides in formulations. The sample is extracted with benzene, and equal amounts of sample and reference solution in the same concentration range are analyzed by gas chromatography, using an electron capture detector and an SE-30/Diatoport S column. The method has been applied successfully to laboratory-prepared and commercial samples.

scholarly journals The Use of Cryogenic Temperature Gas Chromatography for the Determination of Carbon Monoxide and Carbon Dioxide in Cigarette Smoke

1972 ◽  
Vol 6 (4) ◽  
Author(s):  
G.P. Morie ◽  
C.H. Sloan
Keyword(s):  
Carbon Dioxide ◽  
Gas Chromatography ◽  
Carbon Monoxide ◽  
Liquid Nitrogen ◽  
Cigarette Smoke ◽  
Cryogenic Temperature ◽  
Chromatographic Method ◽  
Porapak Q ◽  
Gas Chromatographic Method

AbstractA gas chromatographic method for the determination of carbon monoxide and carbon dioxide in cigarette smoke was developed. A column containing Porapak Q packing and a cryogenic temperature programmer which employed liquid nitrogen to cool the column to subambient temperatures was used. The separation of N

Comparison of Emmerie-Engel Method and Gas Chromatographic Method for Determination of Supplemental α-Tocopheryl Acetate in Feed Concentrates

1987 ◽  
Vol 70 (3) ◽  
pp. 417-419
Author(s):  
Michael P Labadie ◽  
Charles E Boufford
Keyword(s):  
Gas Chromatography ◽  
Vitamin E ◽  
Coefficient Of Variation ◽  
Chromatographic Method ◽  
Tocopheryl Acetate ◽  
High Potency ◽  
Gc Analysis ◽  
Gas Chromatographic Method ◽  
Official Procedure

Abstract The determination of supplemental a-tocopheryl acetate in high potency vitamin E powders and oils was compared using the Emmerie- Engel method and gas chromatography (GC). The Emmerie-Engel reaction requires saponification, extraction of the saponiflable fracaon, and quantitation by colorimetry. GC analysis requires only an extraction and/or dilution before quantitation. These are represented essentially by AOAC methods 43.147-43.151 (colorimetry) and 43.152-43.159 (GC) for high potency vitamin E concentrates. Each method was statistically evaluated for precision and sample-to-sample reproducibility. Each Emmerie-Engel value was divided by the GC value obtained for the same sample; an average of 1.049 with a coefficient of variation of 2.89% was obtained. It was concluded that (he GC procedure was superior to the Emmerie-Engel method, and ahould be the official procedure for determination of supplemental a-tocopheryl acetate in feed concentrates.

Capillary Column Gas Chromatographic Determination of Trace Residues of the Herbicide Chlorsulfuron in Agricultural Runoff Water

1987 ◽  
Vol 70 (4) ◽  
pp. 745-748
Author(s):  
Uaz Ahmad
Keyword(s):  
Gas Chromatography ◽  
Chromatographic Method ◽  
Capillary Column ◽  
Methylene Chloride ◽  
Chromatographic Determination ◽  
Agricultural Runoff ◽  
Runoff Water ◽  
Florisil Column ◽  
Gas Chromatographic Method

Abstract A capillary column gas chromatographic method is described for determining parts-per-trillion (ppt) levels of chlorsulfuron in agricultural runoff water. The water sample is acidified with acetic acid and extracted with methylene chloride. The chlorsulfuron in the extract is derivatized to its monomethyl derivative. After Florisil column cleanup, the methylated chlorsulfuron is determined by electron-capture gas chromatography. Recovery of chlorsulfuron from fortified water samples is greater than 80%. Detection limit of the method is 25 ng chlorsulfuron/L water (25 ppt). There are 2 reaction sites on the chlorsulfuron molecule, both of which are susceptible to methylation leading to monomethyl chlorsulfuron and dimethyl chlorsulfuron. A procedure is described to methylate selectively the sulfonamide nitrogen of chlorsulfuron.

Qualitative and Quantitative Determination of Methaqualone in Serum by Gas Chromatography

1974 ◽  
Vol 20 (2) ◽  
pp. 249-254 ◽  
Author(s):  
M A Evenson ◽  
G L Lensmeyer
Keyword(s):  
Gas Chromatography ◽  
Quantitative Determination ◽  
Chromatographic Method ◽  
Internal Standard ◽  
Serum Concentrations ◽  
Single Extraction ◽  
Qualitative And Quantitative ◽  
Gas Chromatographic Method ◽  
Isothermal Gas

Abstract A rapid, simple, accurate, and precise isothermal gas-chromatographic method is introduced for determination of methaqualone (2-methyl-3-o-tolyl-4(3H)-quinazolinone) in serum. A single extraction of 2 ml of serum, without derivative formation, will give adequate sensitivity for quantitation of therapeutic serum concentrations of the drug within 15 min. The method is free of interferences from biological substances, as well as from commonly used drugs. A non-drug internal standard compensates for variables in extraction, injection, and instrumental changes during analysis. The coefficient of variation, day-to-day, is 5.6%. Mean recovery of added methaqualone was 80%. To compensate for the nonquantitative yield and ensure accurate results, we prepared all analytical methaqualone standards in serum.

Determination of fluoxetine and norfluoxetine in plasma by gas chromatography with electron-capture detection.

1982 ◽  
Vol 28 (10) ◽  
pp. 2100-2102 ◽  
Author(s):  
J F Nash ◽  
R J Bopp ◽  
R H Carmichael ◽  
K Z Farid ◽  
L Lemberger
Keyword(s):  
Gas Chromatography ◽  
Human Plasma ◽  
Electron Capture ◽  
Relative Error ◽  
Chromatographic Method ◽  
Linear Range ◽  
Electron Capture Detector ◽  
Electron Capture Detection ◽  
Gas Chromatographic Method

Abstract This gas-chromatographic method for assay of fluoxetine and norfluoxetine in human plasma involves extraction of the drugs and use of a 63Ni electron-capture detector. The linear range of detection is 25 to 800 micrograms/L for each drug. Overall precision (CV) in the concentration range of 10 to 100 micrograms/L for both drugs was approximately 10%. Accuracy (relative error) in the same concentration range was approximately +10%. None of the commonly prescribed antidepressants or tranquilizers that we tested interfere with the assay.

Gas Chromatographic Determination of Benalaxyl Residues in Different Crops and Water

1993 ◽  
Vol 76 (3) ◽  
pp. 650-656 ◽  
Author(s):  
Teodoro Crisippi ◽  
Guido Zini ◽  
Riccardo Fabbrini
Keyword(s):  
Gas Chromatography ◽  
Column Chromatography ◽  
Active Ingredient ◽  
Chromatographic Method ◽  
Chromatographic Determination ◽  
Standard Deviations ◽  
Gas Chromatographic Method

Abstract A gas chromatographic method is described that is suitable for the determination of benalaxyl residues ranging from 10 to 0.1 μg/kg in several crops, must, wine, and water. The compound is extracted with acetone and purified either by partitioning between water and n-hexane or by passing the extract through an Extrelut column with n-hexane. Further purification is achieved by column chromatography on alumina. The active ingredient is finally determined by gas chromatography with nitrogenphosphorus detection. Mean recoveries were ≥95% in the various crops tested and in the 0.01-1.05 mg/kg fortification range. Standard deviations for each crop were ≤6.5%.

Gas-Liquid Chromatographic Determination of Acephate and Ortho 9006 Residues in Crops

1974 ◽  
Vol 57 (1) ◽  
pp. 189-191
Author(s):  
James B Leary
Keyword(s):  
Gas Chromatography ◽  
Chromatographic Method ◽  
Chromatographic Determination ◽  
Ionization Detector ◽  
Flame Ionization ◽  
Ether Solution ◽  
Liquid Chromatographic Determination ◽  
Gas Chromatographic Method ◽  
Liquid Chromatographic

Abstract A gas chromatographic method is described for determining acephate (O,S-dimethyl acetylphosphoramidothioate) and a metabolite, Ortho 9006 (O,S-dimethyl phosphoramidothioate), in a variety of crops. After extraction of the sample with ethyl acetate, the solvent is evaporated, and an ether solution of the residue is passed through a silica gel column to remove interferences. Acephate and Ortho 9006 are eluted from the column with 10% methanol in ether and measured simultaneously by programmed temperature gas chromatography, using an alkali flame ionization detector.

Selective Determination of Methyl Mercury in Biological Samples by Means of Programmed Temperature Gas Chromatography

1993 ◽  
Vol 76 (3) ◽  
pp. 608-614 ◽  
Author(s):  
R A Lorenzo ◽  
A Carro ◽  
E Rubí ◽  
C Casais ◽  
R Cela
Keyword(s):  
Gas Chromatography ◽  
Biological Samples ◽  
Methyl Mercury ◽  
Chromatographic Method ◽  
Preliminary Treatment ◽  
Selective Determination ◽  
Good Linearity ◽  
Aoac Official ◽  
Gas Chromatographic Method

Abstract A programmed temperature gas chromatographic method is presented by which it is possible to carry out routine analysis of methyl mercury in biological samples prepared according to the AOAC official first action recommendations without the need for preliminary treatment of the columns. This method greatly extends the life of the columns as well as the useful time for analysis; it has good linearity and repeatability. With the proposed method a total of 36 samples can be analyzed daily.

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