from the analytical point of view. All the above-mentioned results
indicated that the acidity of the sample had to be considered when
searching for ASA. 13C NMR spectra were measured for a number
of control urine samples and for urine samples of three patients
with argininosuccinic aciduria. The first sample was from patient
PK from Utrecht, two other urine samples, MD and PM, came from
two Polish infants. The signals of ASA in all three latter cases dominated
those of any other urine component and were very easily
recognizable. In authors opinion, 13C NMR and complementary 1H
NMR spectroscopy are powerful and convenient tools in diagnosing
argininosuccinic acid lyase deficiency [7–9,28]. The conducted
research allowed to develop a new measurement method, which
has become the basic tool used in marking this acid in urine samples
with suspected ASLD