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.

The Ektachem clinical chemistry slide for simultaneous determination of unconjugated and sugar-conjugated bilirubin.

1984 ◽  
Vol 30 (8) ◽  
pp. 1304-1309 ◽  
Author(s):  
T W Wu ◽  
G M Dappen ◽  
R W Spayd ◽  
M W Sundberg ◽  
D M Powers
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Liquid Chromatography ◽  
Magnetic Resonance ◽  
Total Bilirubin ◽  
Clinical Chemistry ◽  
Average Concentration ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic ◽  
Conjugated Bilirubin

Abstract Using dual-wavelength spectrometry, we have refined the mordant-based bilirubin slide method (Clin Chem 28:2366-2372, 1982) to co-detect unconjugated bilirubin (Bu) and its sugar conjugates (Bc) in 10 microL of serum. The assay is based on three principles: (a) mono- and diconjugated bilirubins behave spectrally like one fraction (Bc) when bound to the mordant, (b) Bu and Bc are spectrally distinct, and (c) B delta (the bilirubin-albumin complex) is not measured in the film. With known bilirubin mixtures, results by the assay agree with those by nuclear magnetic resonance, by a Jendrassik-Gróf method for total bilirubin, and by a liquid-chromatographic procedure. With patients' sera, the slide correlates with a liquid-chromatography-augmented Jendrassik-Gróf method, according to the following typical regression statistics (in mumol/L): for Bu, slope = 0.992, r = 0.996, intercept = -0.376, Sy X x = 5.08; for Bc, slope = 0.970, r = 0.985, intercept = -0.735, Sy X x = 8.16. The method is precise (for Bu, CV = 5.2% at an average concentration of 16.4 mumol/L, and 4.1% at 66.7 mumol/L; for Bc, CV = 6.5% at 23.4 mumol/L, and 3.8% at 151.7 mumol/L for pools of patients' sera), is relatively interference free, and has potential for extension to further applications.

Gas-Liquid Chromatographic Determination of Sodium Fluoroacetate (Compound 1080)

1980 ◽  
Vol 63 (1) ◽  
pp. 49-55
Author(s):  
Iwao Okuno ◽  
Dennis L Meeker
Keyword(s):  
Liquid Chromatography ◽  
Tissue Sample ◽  
Chromatographic Determination ◽  
Gas Liquid Chromatography ◽  
Tissue Samples ◽  
Fluoroacetic Acid ◽  
Pentafluorobenzyl Bromide ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract An analytical method is described for the determination of Compound 1080 (sodium fluoroacetate) residues in 1–10 g tissue. Sample extracts of tissues are cleaned up with silica gel, and Compound 1080 (as fluoroacetic acid) is separated by a micro-distillation procedure. The fluoroacetic acid in the distillate is derivatized with pentafluorobenzyl bromide to form pentafluorobenzyl fluoroacetate which is measured by electron capture gas-liquid chromatography. Recoveries of sodium fluoroacetate from fortified tissue samples averaged about 25%. Despite the limited recoveries, results were quite reproducible, and levels as low at 2 ppm were determined in fortified 1 g samples, and 0.2 ppm in 10 g samples. The method is relatively simple and has been used routinely in our laboratory for the analysis of various types of samples such as grain, and tissues from birds, rodents, and larger animals.

Gas-Liquid Chromatographic Determination of Maleic Hydrazide in Tobacco and Tobacco Smoke

1979 ◽  
Vol 62 (1) ◽  
pp. 171-175 ◽  
Author(s):  
Alfred F Haeberer ◽  
Orestes T Chortyk
Keyword(s):  
Liquid Chromatography ◽  
Tobacco Smoke ◽  
Plant Growth Regulator ◽  
Maleic Hydrazide ◽  
Chromatographic Determination ◽  
Gas Liquid Chromatography ◽  
Trimethylsilyl Derivative ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A method is presented for the determination of the plant growth regulator maleic hydrazide (MH; l,2-dihydro-3,6-pyridazinedione) in tobacco and tobacco smoke. Residues are converted to the bis(trimethylsilyl) derivative before analysis by gas-liquid chromatography. The method has been applied to cigarettes and condensed smoke and has been used to determine the per cent transfer of MH into cigarette smoke. Free MH residues could be determined directly on the tobacco samples, whereas total MH values were obtainable only after acid hydrolysis. In spite of large MH residues in tobacco, only 0.2% of the MH was transferred into smoke.

Rapid Determination of Glutethimide (Doriden) by Gas-Liquid Chromatography

1967 ◽  
Vol 13 (7) ◽  
pp. 589-594 ◽  
Author(s):  
Seymour Winsten ◽  
Daniel Brody
Keyword(s):  
Liquid Chromatography ◽  
Rapid Determination ◽  
Gas Liquid Chromatography ◽  
Liquid Chromatographic

Abstract A rapid simple gas liquid chromatographic technic has been developed for the identification and quantitation of glutethimide in biologic fluids. The method requires no evaporation of extracting fluid and will estimate glutethimide levels in the range of 1 mg./100 ml. or higher.

Gas-Liquid Chromatographic Determination of Total Inorganic Iodine in Milk

1977 ◽  
Vol 60 (6) ◽  
pp. 1307-1309 ◽  
Author(s):  
Hendrik J Bakker
Keyword(s):  
Liquid Chromatography ◽  
Iodine Content ◽  
Chromatographic Determination ◽  
Electron Capture Detection ◽  
Gas Liquid Chromatography ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Inorganic Iodine ◽  
Liquid Chromatographic

Abstract Total inorganic iodine in milk is determined by conversion to iodobutanone, which is quantitated by gas-liquid chromatography and electron capture detection. As little as 10 μg/L can be determined. The thyroid-active iodine content of milk can be determined rapidly with a relative standard deviation of 1.9%. Average recoveries for added iodide and iodine were 95.5 and 94.6%, respectively.

Gas-Liquid Chromatographic Determination of Choline in Low and High Potency Multiple Vitamin Tablets and Liver Preparations

1974 ◽  
Vol 57 (2) ◽  
pp. 341-342
Author(s):  
Caesar B Garavelli
Keyword(s):  
Liquid Chromatography ◽  
Quantitative Determination ◽  
Chromatographic Determination ◽  
Gas Liquid Chromatography ◽  
High Potency ◽  
Average Recovery ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A procedure is described for the quantitative determination of 0.020—6.0 mg choline in low and high potency reference multiple vitamin tablets and standard liver preparations. The trimethylamine quantitatively produced in a sealed tube by treatment with aqueous 5 0% alkali is simultaneously extracted with 0.200—0.500 ml of an isobutanol-ethanol (1+1) mixture and determined by gas-liquid chromatography. An average recovery of 100 ± 3 % was obtained.

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