Determination of Amphetamine and Methylamphetamine by Gas-liquid Chromatography (Head Space)

1983 ◽  
Vol 2 (2) ◽  
pp. 391-393 ◽  
Author(s):  
D. Martinez ◽  
M.P. Gimenez
Keyword(s):  
Liquid Chromatography ◽  
Solvent Extraction ◽  
Liquid Phase ◽  
Gas Phase ◽  
Urine Sample ◽  
Urine Samples ◽  
Gas Liquid Chromatography ◽  
Flame Detection ◽  
Therapeutic Doses

1 A method for determining amphetamine and methylamphetamine in urine by gas-liquid chromatography is described. 2 Chromatography is performed on a 10% Apiezon L, 10% KOH column with alkali-flame detection (NPD). This method avoids the losses of these volatile substances which are known to occur when solvent extraction is used. An alkalinized urine sample (1 ml) is introduced into a sealed vial which is heated in a water bath at 70°C for 20 min. A 1 ml portion of the gas phase in equilibrium with the liquid phase is chromatographed. 3 Amphetamine and methylamphetamine can be detected and measured in urine samples after single therapeutic doses of the drugs.

scholarly journals Gas Chromatographic Determination of Traces of Accelerants in Physical Evidence

1972 ◽  
Vol 55 (4) ◽  
pp. 840-845 ◽  
Author(s):  
Charles R Midkiff ◽  
Willard D Washington
Keyword(s):  
Liquid Chromatography ◽  
Solvent Extraction ◽  
Vapor Phase ◽  
Selection Criteria ◽  
Chromatographic Determination ◽  
Operating Parameters ◽  
Gas Liquid Chromatography ◽  
Internal Standards ◽  
Physical Evidence

Techniques developed for use with gas-liquid chromatography for the examination of evidence collected at the scene of suspected arson fires and firebombings are discussed. Both solvent extraction and vapor phase examinations are employed. Internal standards are used for the identification of specific components in actual samples to allow confirmation of hydrocarbon type, e.g., gasoline and kerosene. Operating parameters and solvent selection criteria are included. Results obtained from known materials and residual hydrocarbons in actual samples are compared.

Gas—Liquid Chromatographic Measurement of Guanidino Acids

1975 ◽  
Vol 21 (7) ◽  
pp. 838-843 ◽  
Author(s):  
Harini Patel ◽  
Burton D Cohen
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Liquid Chromatography ◽  
Liquid Phase ◽  
Magnetic Resonance ◽  
Gas Liquid Chromatography ◽  
Butyl Esters ◽  
Silicone Liquid ◽  
Chromatographic Measurement ◽  
Liquid Chromatographic

Abstract We present a method for separating and measuring guanidino acids by gas—liquid chromatography. Compared to ion-exchange techniques, this system is faster, more sensitive, requires smaller sample volumes, is independent of colorimetric reactions, and permits simultaneous determination of both amino and guanidino acids. N-Trifluoroacetyl-n-butyl esters are formed and then are separated by using a column containing a mixed silicone liquid phase coated on Chromosorb W-HP. Analytical recoveries from plasma ranged from 86 to 112% and were optimal when purification and derivatization were done without prior protein precipitation. Speculations as to the cause of this interference by protein include coprecipitation, protein-binding, and cyclization of the guanidines in the acids used for denaturation. Evidence presented suggests that all three occur: ultrafiltrability is diminished in the presence of protein and nuclear magnetic resonance demonstrates cyclization of some of these esters.

Simultaneous Determination of Lactulose and Mannitol in Urine of Burn Patients by Gas-Liquid Chromatography

1992 ◽  
Vol 38 (3) ◽  
pp. 343-345 ◽  
Author(s):  
R L Shippee ◽  
A A Johnson ◽  
W G Cioffi ◽  
J Lasko ◽  
T E LeVoyer ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Simultaneous Determination ◽  
Urine Samples ◽  
Gas Liquid Chromatography ◽  
Burn Patients ◽  
Mucosal Permeability ◽  
Severe Burns ◽  
Urine Concentrations ◽  
Enzymatic Methods

Abstract Ratios of lactulose/mannitol excretion in urine have been used to assess the extent of intestinal permeability in various disease and trauma conditions. Reported studies have used this technique to correlate altered gastrointestinal mucosal permeability to translocation of bacteria and endotoxin, leading to occult sepsis in burn patients. Enzymatic methods of analysis for urine concentrations of mannitol and lactulose were used in these studies. We have found that urine from patients with severe burns frequently contains compounds that interfere with the enzymatic methods. We describe using gas-liquid chromatography to determine mannitol and lactulose simultaneously in the urine of burn patients. To avoid the multiple peaks for the anomeric forms of the reducing sugars during precolumn trimethylsilyl derivatization, we converted the sugars to oximes before the silylation step. The method gave good recoveries of mannitol and lactulose added to burn patients' urine samples. Unlike the enzymatic methods, gas-liquid chromatography eliminates the effect of interfering compounds and allows for the simultaneous determination of both sugars in urine samples.

Quantitative Determination of Benzaldehyde in Flavors by Gas-Liquid Chromatography

1963 ◽  
Vol 46 (6) ◽  
pp. 950-951
Author(s):  
Richard L Brunelle ◽  
Glenn E Martin
Keyword(s):  
Liquid Chromatography ◽  
Liquid Phase ◽  
Benzoic Acid ◽  
Quantitative Determination ◽  
Solid Support ◽  
Specific Method ◽  
Gas Liquid Chromatography ◽  
Ultraviolet Spectrophotometry ◽  
Liquid Chromatography Separation

Abstract A rapid and specific method is given for determination of benzaldehyde in the presence of interfering substances by gas-liquid chromatography. Separation is effected on a ¼ column containing 2 5% Apiezon M as the liquid phase on a solid support of Chromoport XXX (60—80 mesh) at isothermal conditions, 100°C. The determination can be performed in the presence of benzoic acid and other interfering substances. Results are compared with those obtained by ultraviolet spectrophotometry on a variety of almond and cherry flavors.

Profile of Sedatives and Tranquilizers in Serum, as Measured by Gas-Liquid Chromatography

1971 ◽  
Vol 17 (3) ◽  
pp. 222-228 ◽  
Author(s):  
Henning F Proelss ◽  
Herman J Lohmann
Keyword(s):  
Liquid Chromatography ◽  
Solvent Extraction ◽  
Liquid Phase ◽  
Screening Method ◽  
Gas Liquid Chromatography ◽  
Basic Drugs ◽  
Ph Values ◽  
Preliminary Separation ◽  
Glass Columns ◽  
Neutral And Basic Drugs

Abstract We describe here a rapid and comprehensive screening method for 40 commonly used sedatives and tranquilizers with use of gas-liquid chromatography. Barbiturates, nonbarbiturate sedatives, and tranquilizers of the phenothiazine, benzodiazepine, and dibenzazepine type can be both identified and measured in serum. A simple solvent extraction at different pH values, with subsequent solvent partition, effects a preliminary separation into acid, neutral, and basic drugs. The three fractions are separated on two standard 180-cm glass columns: acid and neutral drugs with the liquid phase XE-60 (3.5%) and basic drugs with the liquid phase OV-17(3%). Sera from more than 50 patients have been analyzed by this technique, and the concentrations of several sedatives and tranquilizers are reported.

Fusel Oil Determination by Gas-Liquid Chromatography

1963 ◽  
Vol 46 (2) ◽  
pp. 294-297
Author(s):  
Glenn E Martin ◽  
Gian Caggiano ◽  
Howard Schlesinger
Keyword(s):  
Liquid Chromatography ◽  
Liquid Phase ◽  
Isothermal Condition ◽  
Solid Support ◽  
Gas Liquid Chromatography ◽  
Fusel Oil ◽  
Liquid Chromatography Separation

Abstract A method was developed for the determination of fusel oil by gas-liquid chromatography. Separation is effected in a ¼” column containing 20% Ucon polar as the liquid phase, on a solid support of Gas Chrom P at isothermal condition 90° C. The method is simple and expeditious, and the amount of each component alcohol can be determined individually.

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