Assay for N tau-methylimidazoleacetic acid, a major metabolite of histamine, in urine and plasma using capillary column gas chromatography-negative ion mass spectrometry.
A gas chromatographic-mass spectrometric assay has been developed for the measurement of N tau-methylimidazoleacetic acid in urine and plasma. The method uses the isopropyul ester 3,5-bistrifluoromethylbenzoyl derivative of N tau-methylimidazoleacetic acid and electron capture negative ion chemical ionisation mass spectrometry. The derivative has very good chromatographic properties and a negative ion mass spectrum which contains only a molecular ion at m/z 422. When this ion is specifically monitored, an amount of derivative equivalent to 1 pg of parent compound can be detected. A deuterated analogue of N tau-methylimidazoleacetic acid was synthesised for use as an internal standard and this allowed the development of an assay for N tau-methylimidazoleacetic acid, in urine with a precision of 2.9% and in plasma with a precision of 1.5%.
Murray
S
S
Department of Clinical Pharmacology, Royal Postgraduate Medical School, London, U.K.
O'Malley
G
G
Taylor
I K
IK
Mallet
A I
AI
Taylor
G W
GW
D055598:Chemical Phenomena; D002621:Chemistry; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006632:Histamine / Q000378:metabolism*; D006801:Humans; D007093:Imidazoles / Q000097:blood / Q000378:metabolism* / Q000652:urine
D007093:Imidazoles; C002667:methylimidazoleacetic acid; D006632:Histamine