Urinary 3-methoxy-4-hydroxyphenylacetic (homovanillic) and 3-methoxy-4-hydroxymandelic (vanillylmandelic) acids: gas-liquid chromatographic methods and experience with 13 cases of neuroblastoma.

1977 ◽  
Vol 23 (12) ◽  
pp. 2247-2249 ◽  
Author(s):  
M A Brewster ◽  
D H Berry ◽  
M Moriarty
Keyword(s):  
Homovanillic Acid ◽  
Chromatographic Method ◽  
Internal Standard ◽  
Silyl Ether ◽  
Vanillylmandelic Acid ◽  
Ether Extraction ◽  
Analytical Recovery ◽  
Hydroxyphenylacetic Acid ◽  
Gas Chromatographic Method ◽  
Liquid Chromatographic

Abstract We present a quantitative gas-chromatographic method for determining urinary 3-methoxy-4-hydroxymandelic acid (vanillylmandelic acid) and 3-methoxy-4-hydroxyphenylacetic acid (homovanillic acid). In this rapid technique an internal standard is used and the procedure involves ether extraction and silyl ether formation. Analytical recovery of vanillylmandelic acid averages 87.5% (CV, 0.95%), of homovanillic acid 102.3% (CV, 9.95%). Our data on 34 samples from 13 neuroblastoma patients show that homovanillic acid is more consistently elevated than is vanillylmandelic acid.

Improved simultaneous gas-chromatographic analysis for homovanillic acid and vanillylmandelic acid in urine.

1981 ◽  
Vol 27 (12) ◽  
pp. 2029-2032 ◽  
Author(s):  
C Leiendecker-Foster ◽  
E F Freier
Keyword(s):  
Chromatographic Analysis ◽  
Homovanillic Acid ◽  
Chromatographic Method ◽  
Vanillylmandelic Acid ◽  
Precision Data ◽  
Hydroxyphenylacetic Acid ◽  
Catecholamine Metabolites ◽  
Gas Chromatographic Method ◽  
Improved Technique ◽  
Related Compounds

Abstract We describe an improved gas-chromatographic method for the simultaneous quantitation of the catecholamine metabolites, homovanillic acid (3-methoxy-4-hydroxyphenylacetic acid) and vanillylmandelic acid (3-methoxy-4-hydroxymandelic acid). Our improvements in the method of Muskiet et al. (Clin. Chem. 23: 863, 1977) include a shorter program time and a longer silylation interval. Recovery and precision data obtained by this improved technique are similar to those of Muskiet et al. Vanillylmandelic acid results (y) were compared with those by the method of Pisano et al. (Clin. Chim. Acta 7: 285, 1962). The relation is expressed by the equation y = 0.52 + 1.05x (Sy . x = 2.33 mg/24 h and r = 0.997). Results for homovanillic acid (y) were compared with those by the method of Knight and Haymond (Clin. Chem. 23: 2007, 1977); the equation was y = 0.84 + 0.90x (Sy . x = 2.04 and r = 0.97). Retention times are also reported for several phenolic acids and other related compounds found in urine.

Modification of the AOAC Gas-Liquid Chromatographic Method for Indole in Shrimp: Collaborative Study

1982 ◽  
Vol 65 (4) ◽  
pp. 842-845
Author(s):  
Theodore L Chambers ◽  
◽  
E C Netz ◽  
K Ogger
Keyword(s):  
Silica Gel ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Internal Standard ◽  
Current Method ◽  
Peak Height ◽  
Modified Method ◽  
Liquid Chromatographic Method ◽  
Gas Chromatographic Method ◽  
Liquid Chromatographic

Abstract Several changes were suggested for standardization of the AOAC official final action gas chromatographic method for the determination of indole in shrimp. In a collaborative study, 3 FDA laboratories compared the modified method with the current method. At a 95% confidence level, the same results were obtained for each respective sample by the AOAC or the modified method, which had the following changes. The cleanup column was standardized by drying the silica gel for 2 h at 125°C and equilibrating with 3 g of water/25 g of silica gel. Concentrated ethyl acetate shrimp extracts were treated with anhydrous sodium sulfate before column cleanup and indole was eluted from the column with 15% ethyl ether/hexane. A reduced amount of the internal standard, 2-methylindole, was used to improve peak height measurements at the 25 μg% indole level. The modified method has been adopted official first action to replace method 18.075.

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, Liquid Chromatographic, and Titrimetric Procedures for Determination of Glycerin in Allergenic Extracts and Diagnostic Antigens: Comparative Study

1987 ◽  
Vol 70 (5) ◽  
pp. 825-828
Author(s):  
Alfred V Del Grosso ◽  
Joan C May
Keyword(s):  
Chromatographic Method ◽  
Internal Standard ◽  
Sodium Metaperiodate ◽  
Oxidation Method ◽  
Allergenic Extracts ◽  
Liquid Chromatographic Method ◽  
Chromatographic Procedure ◽  
Gas Chromatographic Method ◽  
Liquid Chromatographic

Abstract Three methods for the determination of glycerin are examined as applied to several allergenic extracts and diagnostic antigens. The liquid chromatographic procedure uses a sulfonic acid functional PSDVB resin (Aminex HPX-87H), a mobile phase of 0.013N H2S04; and refractive index detection. The titrimetric procedure involves oxidation of glycerin with sodium metaperiodate followed by potentiometric titration of the resulting formic acid with sodium hydroxide. Samples are quantitated by comparing the equivalence point obtained from the sample to those obtained from a series of standards. The gas chromatographic procedure includes a column of 5% Carbowax 20 M on 80-100 mesh Chromosorb WHP; p-cresol was used as an internal standard. The 3 procedures are shown to be valid for the majority of product types examined. A positive interference was encountered in the titrimetric analysis of a tuberculin purified protein derivative that contained simple sugars. Recoveries of added glycerin ranged from 95.0 to 100.2% by the liquid chromatographic method, from 98.7 to 101.4% by the gas chromatographic method, and from 99.8 to 101.6% by the metaperiodate oxidation method when interference from simple sugars was not present. Coefficients of variation determined from 8 replicates of samples that contained glycerin were 2.2% or less for the liquid chromatographic method, 2.3% or less for the GC method, and 3.6% or less for the metaperiodate oxidation method.

Liquid-chromatographic determination of vanillylmandelic acid in urine.

1985 ◽  
Vol 31 (6) ◽  
pp. 819-821 ◽  
Author(s):  
G M Anderson ◽  
F C Feibel ◽  
D J Cohen
Keyword(s):  
Liquid Chromatography ◽  
High Performance ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Urine Samples ◽  
Vanillylmandelic Acid ◽  
Analytical Recovery ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Urinary vanillylmandelic acid (VMA) was determined by "high-performance" liquid chromatography with fluorometric (LC-F) and amperometric (LC-EC) detection. Urine samples were first purified on a small, open-bed, reversed-phase preparatory column. VMA and the internal standard (iso-VMA) were then separated by reversed-phase ion-pair liquid chromatography. Analytical recovery of VMA was high (98.3%, SD 3.3%, n = 8), and concentrations measured by LC-F and LC-EC were in excellent agreement (r = 0.996). The LC-F chromatograms of urine samples had fewer late peaks; however, detection limits were lower (15 vs 120 micrograms/L) for the LC-EC method. Typical concentrations of 1-10 mg/L in urine can be measured easily with either method.

Simultaneous liquid-chromatographic determination of urinary vanillylmandelic acid, homovanillic acid, and 5-hydroxyindoleacetic acid.

1988 ◽  
Vol 34 (12) ◽  
pp. 2504-2506 ◽  
Author(s):  
A Gironi ◽  
G Seghieri ◽  
M Niccolai ◽  
P Mammini
Keyword(s):  
Homovanillic Acid ◽  
Clinical Laboratory ◽  
Chromatographic Determination ◽  
Gradient Elution ◽  
Vanillylmandelic Acid ◽  
Liquid Chromatographic Method ◽  
Analytical Recovery ◽  
Hydroxyindoleacetic Acid ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract We describe a liquid-chromatographic method for quantifying, simultaneously by a single procedure, vanillylmandelic acid (VMA), homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5-HIAA) in urine. After solvent extraction of acidified urine, the analytes were chromatographed on a C8 column, with use of a mobile phase of phosphate buffer (20 mmol/L, pH 4.0) and methanol with a variable gradient elution, and detected fluorometrically. We report the analytical recovery, sensitivity, precision, working linear range, and potential for interference from similar molecules or drugs. The results of such tests demonstrate that the proposed method is sensitive and reproducible. It is, furthermore, easy to perform, and thus is suitable for use in the clinical laboratory.

Determination of carbamazepine in blood or plasma by high-pressure liquid chromatography.

1976 ◽  
Vol 22 (7) ◽  
pp. 1070-1072 ◽  
Author(s):  
P M Kabra ◽  
L J Marton
Keyword(s):  
High Pressure ◽  
Chromatographic Method ◽  
Limit Of Detection ◽  
Internal Standard ◽  
High Pressure Liquid Chromatographic ◽  
Blood Constituents ◽  
Liquid Chromatographic Method ◽  
Gas Chromatographic Method ◽  
Liquid Chromatographic

Abstract We described a sensitive and precise high-pressure liquid-chromatographic method in which 5-(p-methylphenyl)-5-phenylhydantoin is used as the internal standard in determining carbamazepine in whole blood or plasma. Carbamazepine is well separated from normal blood constituents in less than 8 min, and other commonly used anticonvulsants do not interfere with the analysis. The sensitivity of this method is adequate to quantitate 0.25 mg of carbamazepine per liter in 2 ml of sample, and the lower limit of detection is 100 ng. Twenty specimens were analyzed by a gas-chromatographic method and by the present method; the resulting correlation coefficient was greater than .980.

Simultaneous measurement of ethosuximide, primidone, phenobarbital, phenytoin, carbamazepine, and their bioactive metabolites by liquid chromatography.

1984 ◽  
Vol 30 (10) ◽  
pp. 1667-1670 ◽  
Author(s):  
C N Ou ◽  
C L Rognerud
Keyword(s):  
Antiepileptic Drugs ◽  
Mobile Phase ◽  
Chromatographic Method ◽  
Internal Standard ◽  
Reversed Phase ◽  
Bioactive Metabolites ◽  
Chromatographic System ◽  
Liquid Chromatographic Method ◽  
Analytical Recovery ◽  
Liquid Chromatographic

Abstract A simple, isocratic liquid-chromatographic method was developed for simultaneously measuring ethosuximide, primidone, phenobarbital, phenytoin, carbamazepine, and their bioactive metabolites within 10 min. The chromatographic system involves a Waters' Radial-NOVA PAK C18 reversed-phase column and acetone/methanol/acetonitrile/10 mmol/L phosphate buffer (10/21/8/61 by vol, pH adjusted to 7.95 with NaOH) as mobile phase. The antiepileptic drugs are extracted from 50 microL of serum by mixing with 50 microL of acetonitrile containing 10 mg of tolybarb per liter as internal standard. After centrifugation, 20 microL of the supernate is injected onto the column and eluted with mobile phase at the rate of 2.8 mL/min at ambient temperature. The column effluent is monitored at 200 nm. The method can detect the five antiepileptic drugs in concentrations as low as 0.5 mg/L. Analytical recovery ranges from 98 to 102%. Within-run CV ranged from 2.9 to 5.8% and between-run CV from 4.7 to 7.1%. The method can also be used to measure N-desmethyl-methsuximide, chloramphenicol, and pentobarbital.

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