DETERMINATION OF MIMOSINE AND 3,4-DIHYDROXYPYRIDINE IN MILK AND PLASMA OF GOATS

A simple method for determination of mimosine and 3,4-dihydroxypyridin e (3,4-DHP) in plasma and milk was developed. Milk and plasma, with ty rosine as internal standard, were deproteinized using 9% trichloraceti c acid and extracted with diethyl ether. Metabolites were separated by isocratic high-performance liquid chromatography, with 0.02 M orthoph osphoric acid (pH 2.5) at 0.5 ml/min and a Hypersil ODS microbore colu mn. Mimosine, 3,4-DHP and tyrosine were detected at 275 nm. The recove ry of the mimosine added to the plasma samples was 101.6+/-2.3% and 10 3.3+/-1.0% for milk samples. 3,4-DHP recovery for plasma samples was 1 01.2+/-0.9% and for milk samples 100.8+/-1.4%. The reproducibility of the method was evaluated by analyzing six plasma samples and six goat milk samples. The analyses yielded relative standard deviations of 2.6 5 and 2.82%, respectively.