Biomedical subjects

B J Verhaeghe

Publications and source records attributed to B J Verhaeghe.

5 recordsLinked to original sources

PubMed1992

Gas chromatographic/mass spectrometric identification of 3-hydroxydicarboxylic acids in urine.

Organic acid profiles were routinely analysed for two patients suffering from a massive 3-hydroxydicarboxyluria and five patients suffering from ketoaciduria. The identification of the urinary, saturated and unsaturated 3-hydroxydicarboxylic acids as their trimethylsilyl derivatives was performed with electron impact and positive chemical ionization gas chromatography/mass spectrometry. Additionally, their methylene units have been determined on SE-52 and OV-1701 types of stationary phases.

Dicarboxylic Acids↗

PubMed1989

Determination of pipecolic acid in serum or plasma by solid-phase extraction and isotope dilution mass spectrometry.

The determination of pipecolic acid in serum or plasma by positive chemical ionization gas chromatography/mass spectrometry is assessed. This quantitative method involves stable isotope dilution and cation-exchange solid-phase extraction. Several derivatives of pipecolic acid and its octadeuterated analogue were investigated for their mass spectrometric characteristics. The heptafluorobutyric methyl ester derivatives afford optimal resolution on gas chromatography of biological extracts. Moreover, the derivatizing reagent (methanolic HCl) allows a combined elution and derivatization. Selected ion monitoring is performed on the [M + H]+ ions of both analyte and internal standard, at m/z 340 and 348, respectively. Serum or plasma samples from healthy subjects and patients suspected of peroxisomal diseases have been examined.

Child↗

PubMed1989

Metabolic profiling of urinary organic acids by single and multicolumn capillary gas chromatography.

High-resolution gas chromatography (HRGC) and gas chromatography/mass spectrometry (GC/MS) are the techniques of choice to determine the retention indices of more than 200 organic acids as their trimethylsilyl (TMS) or oxime-trimethylsilyl derivatives. Several types of apolar and semipolar fused-silica capillary columns (OV-1, SE-52, and OV-1701), used to analyze and separate organic acids isolated from urine samples, are evaluated.

Acids↗

PubMed1988

Automated profiling of urinary organic acids by dual-column gas chromatography and gas chromatography/mass spectrometry.

A multi-stage screening and identification scheme for the diagnosis of inborn errors in amino acid, fatty acid, carbohydrate and intermediary metabolism is described. The method is based on a computerized analysis of data obtained with dual-column gas chromatography/FID (GC/FID) and gas chromatography/mass spectrometry (GC/MS) profiling of urinary organic acids. It involves: (1) isolation of the compounds by solvent or solid-phase extraction; (2) conversion into trimethylsilyl (TMS) or TMS-oxime derivatives; (3) GC/FID analysis on SE-52 and OV-1701 capillary columns; (4) tentative identification by comparing the methylene unit (MU) values on both columns with a user-built library of reference compounds; (5) quantitative evaluation of the excretion profile; and (6) analysis by GC/MS of samples with an abnormal profile using an automated peak identification programme.

Acids↗

PubMed1988

Solid-phase extraction with strong anion-exchange columns for selective isolation and concentration of urinary organic acids.

This is a new method for isolating and concentrating urinary organic acids before gas chromatography--mass spectrometry. Sulfate and phosphate anions are removed by precipitation with Ba(OH)2, and the urine pH is adjusted to 8-8.5. The sample is then applied onto small, disposable, strong-anion-exchange columns. Neutral and basic compounds are washed out with water, which is then removed by centrifugation and by rinsing the columns with methanol and diethyl ether. The organic acids are eluted with a 4/1 (by vol) mixture of an organic solvent--either n-butanol or ethyl acetate--and formic acid containing HSO4- (0.1 mol/L) as a highly selective counter-ion, and finally with methanol alone. Sulfate ions are retained, and the eluate is evaporated before trimethylsilyl derivatization. Analytical recoveries (about 100%) of organic acids compare favorably with those obtained with solvent extraction. This convenient procedure is selective and reproducible and is a suitable alternative to the more cumbersome diethylaminoethyl-Sephadex extraction method.

Acetates↗