Recommendations for urinary organic acids analysis

Abstract We assessed the quantitative performances of a classical method for profiling urinary organic acids: ethyl acetate extraction/oxime-trimethylsilyl derivatization/GC-MS. Twenty-seven acids were quantified on the basis of specific ions in both scan and selected-ion monitoring modes. We found that the tuning of the mass detector severely affects the calibration factors, being critical to achieve quantitative results, and we propose a practical procedure for reproducible tuning. Of seven compounds tested, tropic acid was retained as the internal standard suitable for most of the acids of clinical interest; a second internal standard, 2-ketocaproic acid, was used in quantifying keto-acids. The within-day and total relative standard deviations (CVs), estimated from scan-mode analyses of urine, ranged from 2.6% to 12.7% and from 4.2% to 11.8%, respectively. Curvilinear relationships between analytical response and concentration were observed for most of the acids investigated.

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Extraction of urinary organic acids by combined barium salt precipitation-anion exchange.

Clinical Chemistry ◽

10.1093/clinchem/23.5.901 ◽

1977 ◽

Vol 23 (5) ◽

pp. 901-903 ◽

Cited By ~ 6

Author(s):

J A Thompson

Keyword(s):

Organic Acids ◽

Anion Exchange ◽

Barium Salt ◽

Salt Precipitation ◽

Urinary Organic Acids

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

Clinical Chemistry ◽

10.1093/clinchem/26.13.1847 ◽

1980 ◽

Vol 26 (13) ◽

pp. 1847-1853 ◽

Cited By ~ 103

Author(s):

K Tanaka ◽

A West-Dull ◽

D G Hine ◽

T B Lynn ◽

T Lowe

Keyword(s):

Organic Acids ◽

Chromatographic Method ◽

Normal Subjects ◽

Retention Indices ◽

Organic Aciduria ◽

Organic Acidurias ◽

Urinary Organic Acids ◽

Urinary Organic Acid Analysis ◽

Gas Chromatographic Method ◽

Extensive List

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.

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Rapid Profiling of Urinary Organic Acids Due to Inherited Metabolic Disorders by Liquid Ionization Mass Spectrometry.

Journal of the Mass Spectrometry Society of Japan ◽

10.5702/massspec.43.189 ◽

1995 ◽

Vol 43 (4) ◽

pp. 189-201 ◽

Cited By ~ 4

Author(s):

Yukio YOKOYAMA ◽

Naoyuki OHMORI ◽

Masahiko TSUCHIYA

Keyword(s):

Mass Spectrometry ◽

Organic Acids ◽

Metabolic Disorders ◽

Ionization Mass Spectrometry ◽

Ionization Mass ◽

Urinary Organic Acids ◽

Inherited Metabolic Disorders ◽

Liquid Ionization

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Metabolic profiles of urinary organic acids recovered from absorbent filter paper.

Clinical Chemistry ◽

10.1093/clinchem/33.4.572 ◽

1987 ◽

Vol 33 (4) ◽

pp. 572-576 ◽

Cited By ~ 19

Author(s):

B A Chamberlin ◽

C C Sweeley

Keyword(s):

Young Children ◽

Organic Acids ◽

Filter Paper ◽

Metabolic Profiles ◽

Sample Storage ◽

Organic Acidurias ◽

Urinary Organic Acids ◽

Specimen Collection ◽

Normal Urine

Abstract We evaluated for reliability and reproducibility a semiquantitative gas-chromatographic assay of organic acids in samples of normal urine recovered from absorbent filter paper. We also evaluated this method for use in diagnosis of some of the more common organic acidurias. Transfer of urine from diapers to absorbent filter paper eases the usual trauma of specimen collection from young children; it also simplifies sample storage and shipment.

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