Simplified determination of urinary delta-aminolevulinic acid in a wide range of concentrations.

1979 ◽  
Vol 25 (4) ◽  
pp. 581-583
Author(s):  
H D Fiorentina ◽  
M Grogna ◽  
F Dewiest
Keyword(s):  
Chromatographic Method ◽  
Analytical Procedure ◽  
Aminolevulinic Acid ◽  
Internal Standard ◽  
Standard Addition ◽  
Simple Method ◽  
Wide Range ◽  
Arch Environ Health

Abstract We describe a simple method for measuring delta-aminole-vulinic acid in urine without the need for the seldom-used but time-consuming internal-standard addition step. It combines the analytical procedure described by Tomokuni and Ogata [Clin. Chem. 18, 1534 (1972)] and a correction based on urine density to obtain, more rapidly and less expensively, results as accurate as those given by the Davis and Andelman [Arch. Environ. Health 15, 53 (1967)] chromatographic method.

Gas Chromatographic Determination of Histapyrrodine Hydrochloride in Pharmaceutical Preparations

1986 ◽  
Vol 69 (4) ◽  
pp. 612-613
Author(s):  
Ramesh T Sane ◽  
Vipul J Doshi ◽  
Sanjay K Joshi ◽  
Vijay K Shastri ◽  
Dhananjay S Sapre ◽  
...  
Keyword(s):  
Chromatographic Method ◽  
Internal Standard ◽  
Pharmaceutical Preparations ◽  
Chromatographic Determination ◽  
Chlorpheniramine Maleate ◽  
Accuracy And Precision ◽  
Label Claim ◽  
Gas Chromatographic Method

Abstract A simple gas chromatographic method is described for the determination of histapyrrodine HC1 in marketed formulations. Chlorpheniramine maleate is used as the internal standard. The amount of histapyrrodine HC1 found by the proposed method averaged 19.91 mg/tablet, compared with the label claim of 20 mg/tablet. The method was statistically evaluated for accuracy and precision.

A sensitive liquid-chromatographic method for determination of 3'-azido-3'-deoxythymidine (AZT) in plasma and urine.

1988 ◽  
Vol 34 (8) ◽  
pp. 1565-1568 ◽  
Author(s):  
M A Hedaya ◽  
R J Sawchuk
Keyword(s):  
Human Plasma ◽  
Prescription Drugs ◽  
Chromatographic Method ◽  
Internal Standard ◽  
Infectious Complications ◽  
Over The Counter ◽  
Internal Standards ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic

Abstract We describe a liquid-chromatographic assay for AZT in human plasma and urine. This assay involves the use of two internal standards, allowing reference of AZT peaks to the appropriate internal standard, the choice depending on the range of concentrations encountered. This method is isocratic, specific, sensitive enough to allow quantification of AZT in concentrations observed clinically, and requires only 13 min of chromatographic time. We saw no interference from various over-the-counter and prescription drugs often used in treating the infectious complications of AIDS.

Gas-Liquid Chromatographic Determination of T-2 Toxin in Plasma

1983 ◽  
Vol 66 (4) ◽  
pp. 909-912 ◽  
Author(s):  
Steven P Swanson ◽  
Venkatachalam Ramaswamy ◽  
Val R Beasley ◽  
William B Buck ◽  
Harold H Burmeister
Keyword(s):  
Chromatographic Method ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Aqueous Sodium Hydroxide ◽  
Chromatographic Determination ◽  
Florisil Column ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract The gas-liquid chromatographic method for the determination of T-2 toxin in plasma is described. The toxin is extracted with benzene, washed with aqueous sodium hydroxide, and chromatographed on a small Florisil column; the heptafluorobutyryl derivative is prepared by reaction with heptafluorobutyrylimidazole. The T-2 HFB derivative is chromatographed onOV-1 at 230°C and measured with an electron capture detector. Iso-T-2, an isomer of T-2 toxin, is added to samples as an internal standard before extraction. Recoveries averaged 98.0 ± 5.5% at levels ranging from 50 to 1000 ng/m L. The limit of detection is 25 ng/mL.

Liquid-chromatographic method for determination of homovanillic acid in plasma, with electrochemical detection.

1987 ◽  
Vol 33 (1) ◽  
pp. 72-75 ◽  
Author(s):  
M Zumárraga ◽  
I Andia ◽  
B Bárcena ◽  
M I Zamalloa ◽  
R Dávilla
Keyword(s):  
Electrochemical Detection ◽  
Homovanillic Acid ◽  
Chromatographic Method ◽  
Detection Sensitivity ◽  
Simple Method ◽  
Liquid Chromatographic Method ◽  
Analytical Recovery ◽  
Standard Additions ◽  
Liquid Chromatographic

Abstract We describe a sensitive, simple method for measuring homovanillic acid in human plasma. The method is based on liquid chromatography with electrochemical detection. Sensitivity was 125 pg of homovanillic acid per injection. Samples were deproteinized and extracted with organic solvent before chromatography. Quantification was by the standard-additions technique. Analytical recovery of added HVA was 44.8 (SD 6.2%). We confirmed specificity by using serial amperometric detectors.

Gas-chromatographic determination of 5-fluorocytosine in human serum.

1976 ◽  
Vol 22 (6) ◽  
pp. 772-776 ◽  
Author(s):  
S A Harding ◽  
G F Johnson ◽  
H M Solomon
Keyword(s):  
Chromatographic Method ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Mean Value ◽  
Normal Serum ◽  
Trimethylsilyl Derivative ◽  
Serum Samples ◽  
Gas Chromatographic Method

Abstract We describe a sensitive and precise gas-chromatographic method, in which cytosine is used as the internal standard, for determination of an antifungal agent, 5-fluorocytosine, in serum. The trimethylsilyl derivative of this drug is well separated from the internal standard and from normal serum constituents. Amphotericin B does not interfere with the determination of 5-fluorocytosine. The lower limit of detection for 5-fluorocytosine is 1 mg/liter when 200 mul of serum is analyzed. Within-run precision (CV), established by analysis of 10 replicates, was 4.5% at a concentration of 19.9 mg/liter. Twenty-five serum samples were analyzed for 5-fluorocytosine by a microbiological assay and by the gas-chromatographic method. Mean value observed with the bioassay was 78.5 mg/liter and with our procedure was 69.4 mg/liter. When values for our assay were regressed against values for the bioassay, slope of the least-squares line was 0.85, intercept was 2.7 mg/liter, and r was 0.93.

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.

Gas Chromatographic Method for Determination of Diethylstilbestrol in Feeds

1969 ◽  
Vol 52 (1) ◽  
pp. 107-109 ◽  
Author(s):  
I E Smiley ◽  
E D Schall
Keyword(s):  
Chromatographic Method ◽  
Internal Standard ◽  
Commercial Feed ◽  
Gas Chromatographic Method ◽  
Feed Samples

Abstract A GLC method was developed for the determination of diethylstilbestrol in feeds within the 0.0011–0.0022% range, using dienestrol diacetate as an internal standard. A 10 g sample was extracted with 7% ethanol in chloroform and subjected to a modified alkaline cleanup. The bis-(trimethylsilyl) acetamide derivative was then prepared and determined by GLC. No interference was encountered with commercial feed samples.

Liquid Chromatographic Method for Quantitative Determination of Free Fatty Acids in Butter

1984 ◽  
Vol 67 (4) ◽  
pp. 718-721 ◽  
Author(s):  
Alan W Reed ◽  
Hilton C Deeth ◽  
Donald E Clegg
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Chromatographic Method ◽  
Water System ◽  
Internal Standard ◽  
Detection Range ◽  
Water Solvent ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method has been developed for the determination of free fatty acids in butter. The fatty acids are converted to the p-bromophenacyl esters, via a crown ether-catalyzed reaction, without separation from the other butter components. The esters are separated on a Cis-bonded silica column by using an acetonitrile-water solvent gradient and quantitated using the ester of heptadecanoic acid as internal standard. Cu, and C ,S:i co-elute in the acetonitrile-water system but are separated using an isocratic methanol-acetonitrile-water system. Limits of detection range from 7 ng for butyric acid to 45 ng for linoleic acid. The average coefficient of variation (n = 10) for 10 free fatty acids from,a butter was 5.83%.

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