Chemical analysis of succinylacetone and 4-hydroxyphenyllactate in amniotic fluid using selective ion monitoring

Abstract

A method for the measurement of the concentration of succinylacetone and 4‐hydroxyphenyllactic acid in amniotic fluid was developed for the prenatal diagnosis of hereditary tyrosinemia. Succinylacetone was converted to 5‐methyl‐3‐isoxazolepropionic acid and isolated with 4‐hydroxyphenyllactic acid by liquid partition chromatography and the trimethylsilyl derivatives quantified by ammonia chemical ionization selected ion monitoring gas chromatography‐mass spectrometry with 2‐hydroxy‐n‐caproic acid as the internal standard. The concentration of 4‐hydroxyphenyllactic acid in normal amniotic fluid was 1.97±0.75 (S.D.) μmol/l while succinylacetone was undetectable. A pregnancy at risk for tyrosinemia type II was monitored. The concentration of 4‐ hydroxyphenyllactic acid was within the normal range and a healthy child was born.