Stable isotope dilution analysis of succinylacetone using electron capture negative ion mass fragmentography: an accurate approach to the pre- and neonatal diagnosis of hereditary tyrosinemia type I.
A sensitive and accurate isotope dilution assay using electron capture negative ion mass fragmentography was developed for succinylacetone in amniotic fluid, plasma and urine. The method utilizes (D4)-5(3)-methyl-3(5)-isoxasole propionic acid as internal standard. Sample pretreatment consisted of oximation at pH less than 2 to 5(3)-methyl-3(5)-isoxasole propionic acid, clean up using liquid partition chromatography and further derivatization to the pentafluorobenzyl ester. Control values in plasma revealed a mean means = 0.044 mumol/l, range = 0.005-0.163 mumol/l, in urine means = 0.15 mumol/l, range 0.01-0.40 mumol/l corresponding to means = 0.03 mumol/mmol creat., range 0.01-0.14 mumol/mmol creat., and in amniotic fluid means = 0.016 mumol/l, range = 0.001-0.030 mumol/l. The utility of the method was demonstrated by quantification of succinylacetone in urine from patients with hereditary tyrosinemia type I (n = 8, excretion range 2.60-493.3 mumol/l corresponding to 0.67-197.3 mumol/mmol creat.) and in two amniotic fluid samples from fetuses affected with this disorder (concentration of succinylacetone 0.085 and 1.50 mumol/l, respectively). Maternal urine from a woman carrying an affected fetus did not show elevated urinary succinylacetone excretion.
Jakobs
C
C
Department of Pediatrics, Free University Hospital Amsterdam, The Netherlands.
Dorland
L
L
Wikkerink
B
B
Kok
R M
RM
de Jong
A P
AP
Wadman
S K
SK
D000592:Amino Acid Metabolism, Inborn Errors / Q000175:diagnosis* / Q000378:metabolism; D004583:Electrons; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006537:Heptanoates / Q000032:analysis*; D006538:Heptanoic Acids / Q000032:analysis*; D006801:Humans; D011247:Pregnancy; D011865:Radioisotope Dilution Technique; D014443:Tyrosine / Q000097:blood* / Q000378:metabolism
D006537:Heptanoates; D006538:Heptanoic Acids; D014443:Tyrosine; C020804:succinylacetone