Gas-chromatographic method of analysis for urinary organic acids. II. Description of the procedure, and its application to diagnosis of patients with organic acidurias.

Abstract

A gas-chromatographic method for urinary organic acid analysis is described, designed to be used routinely for the diagnosis of organic aciduria. It involves extraction of urine with ethyl acetate, dehydration of extract residues, and trimethylsilylation. Organic acids are identified by using an extensive list of retention indices published in the accompanying paper (this issue). Quantitative values are given for organic acids in urines from 50 ostensibly normal subjects. Typical chromatograms of urinary organic acids from patients with eight well-established organic acidurias are also shown.

Development of electrospray ionization tandem mass spectrometry methods for the study of a high number of urine markers of inborn errors of metabolism

“…The large amount of information obtained from the multiple analyte assay, using positive and negative MS/MS ionization, can be useful as a starting point for establishing the correct diagnosis of a wide number of IEMs (organic acidurias, fatty acid oxidation disorders, metabolic disorders of amino acids, disorders of purine and pyrimidine metabolism) . This MS/MS method is faster than the traditional GC or HPLC methods . The short analytical run time (2.5 min for positive and 2.6 min for negative ionization methods) allows a daily analysis of a high number of samples which will be applicable for screening purposes.…”

“…The use of gas chromatography coupled with mass spectrometry (GC/MS) for the analysis of liquid urine samples is the key for the clinical diagnosis and the confirmation of many organic acidurias. However, the laborious sample preparation, the long analysis time (>40 min), and the use of liquid samples, does not permit the application of this technique to NBS programs . To solve these limitations, GC/MS variants were developed to simplify the sample preparation and to reduce the analytical time; furthermore, the use of urine spot samples was also implemented .…”

Hereditary non‐spherocytic haemolytic anaemia due to red blood cell glutathione synthetase deficiency in four unrelated patients from Spain: clinical and molecular studies

“…Malonyldialdehyde (MDA) production by patients' RBCs was measured after in vitro incubation of the cells in the presence of hydrogen peroxide (H 2 O 2 ) and 2-thiobarbituric acid (Stocks & Dormandy, 1971). Urine 5-oxoproline was determined using a gas chromatographic method (Tanaka et al, 1980). In one case, RBC membrane ionic transport was measured by flame photometry (Eppendorf Elex 6361) using the method described by Glader et al (1974).…”

Significance of bound glutarate in the diagnosis of glutaric aciduria type I

“…Urine and plasma glutarylcarnitine was determined by FAB-MS/MS. Isolation of organic acids was done as described previously (Tanaka et al 1980) except that the urine samples were extracted three times with 2-ml portions of ethyl acetate and three times with 2-ml portions of diethyl ether. Trimethylsilyl derivatives were produced using BSTFA-pyridine and analysed by gas chromatography-mass spectrometry to confirm the identities of the compounds.…”