Analysis of amino acids is complicated by treatment with ampicillin. H
igh voltage electrophoresis, which is convenient for the qualitative a
ssessment of metabolic diseases, yields smears of ampicillin that mask
the bands of citrulline, homocitrulline, phenylalanine, cystine, and
homocystine. The addition of penicillinase prior to high voltage elect
rophoresis eliminates ampicillin and other penicillins and reveals the
se key amino acids.