Gas Chromatographic Determination of Hydrogen, Nitrogen, Oxygen, Methane, Krypton, and Carbon Dioxide at Room Temperature

1970 ◽  
Vol 8 (9) ◽  
pp. 550-551 ◽  
Author(s):  
G. C. Carle
Keyword(s):  
Carbon Dioxide ◽  
Room Temperature ◽  
Chromatographic Determination

Improved liquid-chromatographic determination of haloperidol in plasma.

1984 ◽  
Vol 30 (7) ◽  
pp. 1228-1230 ◽  
Author(s):  
A K Dhar ◽  
H Kutt
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Room Temperature ◽  
Internal Standard ◽  
Isoamyl Alcohol ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract This method for determination of haloperidol in plasma is based on "high-performance" isocratic liquid chromatography with the use of a C8 bonded reversed-phase column at room temperature. Haloperidol and the internal standard (chloro-substituted analog) are extracted from alkalinized plasma into isoamyl alcohol/heptane (1.5/98.5 by vol) and back-extracted into dilute H2SO4. The aqueous phase is directly injected onto the column. The mobile phase is a 30/45/25 (by vol) mixture of phosphate buffer (16.5 mmol/L, pH 7.0), acetonitrile, and methanol. Unlike other liquid-chromatographic procedures for haloperidol, commonly used psychotropic drugs do not interfere. Analysis can be completed within an hour. The procedure is extremely sensitive (1.0 microgram/L) and is well reproducible (CV 5.6% for a 2.5 micrograms/L concentration in plasma).

Gas-Solid Chromatographic Determination of Oxygen, Nitrogen, Carbon Dioxide, Ethylene, and Nitrous Oxide at Ambient Temperature

1973 ◽  
Vol 56 (1) ◽  
pp. 119-123
Author(s):  
Martin J Finkelson
Keyword(s):  
Carbon Dioxide ◽  
Nitrous Oxide ◽  
Ambient Temperature ◽  
Molecular Sieve ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Digital Integrator ◽  
In Series ◽  
Peak Areas

Abstract A gas-solid chromatographic method is described for the separation and determination of 5 medicinal gases at ambient temperature, using 2 gas chromatographic columns, Porapak Q and Molecular Sieve 13X, operated in series with a 6-port thermal conductivity detector and I recorder. An electronic digital integrator is used for calculating peak areas. Data on retention time, linearity, reproducibility of injection, and comparison with absorption methods are presented. Analytical results for oxygen, nitrogen, carbon dioxide, ethylene, and nitrous oxide are attainable within 1.0% without the use of an internal standard.

Headspace Sampling and Gas Chromatographic Determination of Styrene Migration from Food-Contact Polystyrene Cups into Beverages and Food Simulants

1981 ◽  
Vol 64 (5) ◽  
pp. 1122-1130 ◽  
Author(s):  
Sandra L Varner ◽  
Charles V Breder
Keyword(s):  
Gas Chromatography ◽  
Room Temperature ◽  
Detection Limits ◽  
Chromatographic Determination ◽  
Headspace Sampling ◽  
Ionization Detector ◽  
Migration Studies ◽  
Flame Ionization ◽  
And Storage

Abstract Migration studies using coffee, tea, water, and 8% ethanol were conducted with various types of foodcontact polystyrene cups. Study conditions simulated filling and storage at room temperature and hot-filling or pasteurization above 150°F (65.6°C). The quantity of styrene migrating was determined by headspace sampling and gas chromatography (GC). The GC column was 6% Carbowax 20M on Chromosorb 101 with quantitation via a flame ionization detector. Detection limits ranged from 3 to 10 ppb in various liquids. The method and results of the migration studies are presented.

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 Chromatographic Determination of Glucono-δ-Lactone in Foods

1983 ◽  
Vol 66 (6) ◽  
pp. 1532-1534
Author(s):  
Taizo Tsuda ◽  
Hiroshi Nakanishi
Keyword(s):  
Detection Limit ◽  
Room Temperature ◽  
Chromatographic Determination ◽  
Soybean Curd ◽  
Standard Deviations

Abstract A method is described for the gas chromatographic (GC) determination of glucono-δ-lactone in foods. A sample was homogenized with 60-70°C water and filtered. The filtrate was buffered with NH4OHNH4CI pH 10 solution, and was passed through a QAE-Sephadex A25 column. The column was washed with water and glucono-δ-lactone was eluted with 0.1N HC1. An aliquot of the eluate was evaporated to dryness and derivatized with pyridine, N,O-bis(trimethylsilyl)trifluoroacetamide, and trimethylchlorosilane at room temperature. GC separation of glucono-δ-lactone as the TMS derivative was performed on a 2% OV-17 column at 180°C. Recoveries from bread, jelly, soybean curd, and other foods fortified with 0.1% glucono-δ-lactone ranged from 92 to 106%, with standard deviations from 2.2 to 9.8%. The detection limit was approximately 0.025%.

Gas-Solid Chromatographic Determination of Carbon Monoxide and Carbon Dioxide in Cigarette Smoke

1974 ◽  
Vol 57 (1) ◽  
pp. 1-7
Author(s):  
Arthur D Horton ◽  
Michael R Guerin
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Gas Phase ◽  
Confidence Intervals ◽  
Cigarette Smoke ◽  
Chromatographic Determination ◽  
Standard Errors ◽  
Sampling Techniques ◽  
Relative Standard

Abstract Gas-solid chromatographic methods are presented for the determination of carbon monoxide, carbon dioxide, or both simultaneously in the gas phase of cigarette smoke. The methods are optimized to allow quantitative determinations on the entire gas phase delivery of the cigarettes rather than single puffs and to allow the use of small numbers of cigarettes. Shortcomings of several sampling techniques are defined, and evidence is presented supporting the utility of Saran bag sampling and containment. Carbon monoxide and carbon dioxide analyses may be performed with relative standard errors of 2—3% and relative confidence intervals (95%) of 6—9% for determinations involving 4—6 cigarettes.

Gas Chromatographic Determination of Oxalic Acid in Foods

1985 ◽  
Vol 68 (1) ◽  
pp. 108-111 ◽  
Author(s):  
Hironori Ohkawa
Keyword(s):  
Hydrochloric Acid ◽  
Oxalic Acid ◽  
Room Temperature ◽  
Chromatographic Determination ◽  
Water Soluble ◽  
Small Samples ◽  
Dimethyl Oxalate ◽  
Sample Extract ◽  
Limit Of Determination

Abstract A new quantitative gas chromatographic (GC) method has been developed for the determination of oxalic acid in foods. Solid sample is extracted with water (soluble oxalic acid) or 2N hydrochloric acid (total oxalic acid) at room temperature. An aliquot of sample extract is evaporated to dryness, and the oxalic acid in the residue is methylated with 7% hydrochloric acid-methanol. The reaction mixture is extracted with chloroform, and dimethyl oxalate is quantitated by GC. Recovery of oxalic acid added to liquid samples averaged 100.6%; recoveries from extracts of solid samples were 96.2-99.5 and 97.2-100.1% for water and hydrochloric acid extractions, respectively. Results are shown for determination of oxalic acid in spinach and beverages. The technique is simple, rapid, and accurate, and small samples may be used. The limit of determination is 20 μg.

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