The colorimetric method for the determination of methylmalonic acid by coupling with diazotised p-nitroaniline has been re-examined. Extraction of the diazotised product into amyl alcohol and tetra-methyl ammonium hydroxide considerably increases its stability and sensitivity and reduces background absorbance. Preliminary solvent extraction and ion-exchange chromatography are desirable but can be accomplished simply and quickly using very small quantities of urine. In this form, the method is very reliable and gives recoveries of about 95% and a coefficient of variation of about 7%.
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References
1.
BashirH. V.HinterbergerH.JonesB. P. (1966). Methylmalonic acid excretion in vitamin B12 deficiency. British Journal of Haematology, 12, 704–711.
2.
CoxE. V.WhiteA. M. (1962). Methylmalonic acid excretion: an index of vitamin B12 deficiency. Lancet, 2, 853–856.
3.
DaleR. A. (1972). The assay of methylmalonic acid in urine. Clinica chimica acta, 41, 141–147.
4.
DegraziaJ. A.FishM. B.PollycoveM.PannamperumaM. (1969). The determination of precursors to urinary methylmalonic acid in man: measurement of urinary excretion and specific activity. Clinica chimica acta, 23, 279–287.
5.
DreyfusP. M.DubeV. E. (1967). The rapid detection of methylmalonic acid in urine—a sensitive index of vitamin B12 deficiency. Clinica chimica acta, 15, 525–528.
6.
GiorgioA. J.PlautG. W. E. (1965). A method for the colorimetric determination of urinary methylmalonic acid in pernicious anaemia. Journal of Laboratory and Clinical Medicine, 66, 667–676.
7.
GompertzD.JonesJ. HywelKnowlesJ. P. (1967). Metabolic precursors of methylmalonic acid in vitamin B12 deficiency. Clinica chimica acta, 18, 197–204.
8.
GreenA. (1968). Colorimetric method for estimating methylmalonic acid in urine. Journal of Clinical Pathology, 21, 221–222.
9.
GreenA.PegrumG. D. (1968). Value of estimating methylmalonic acid excretion in anaemia. British Medical Journal, 3, 591–592.
10.
GutteridgeJ. M. C.WrightE. B. (1970). A simple and rapid thin-layer chromatography technique for the detection of methylmalonic acid in urine. Clinica chimica acta, 27, 289–291.
11.
MahoneyM. J.RosenbergL. E.MuddS. H.UhlendorfB. W. (1971). Defective metabolism of vitamin B12 in fibroblasts from children with methylmalonic aciduria. Biochemical and Biophysical Research Communications, 44, 375–381.
12.
RosenbergL. E.LilljeqvistA. C.HsiaY. E. (1968). Methylmalonic aciduria: metabolic block localisation and vitamin B12 dependency. Science, 162, 805–807.
13.
WhiteheadT. P. (1977). Quality Control in Clinical Chemistry. John Wiley: London and New York.
14.
WilliamsD. L.SprayG. H.NewmanG. E.O'BrienJ. R. P. (1969). Dietary depletion of vitamin B12 and the excretion of methylmalonic acid in the rat. British Journal of Nutrition, 23, 343–352.
