Abstract
After irradiation with UV-light a significant change in the UV-spectra of a number of barbiturates has been observed. The photochemical reaction results mainly in a bathochromic shift and appearance of a strong spectral band at 270nm, due to a dealkylation reaction in position 5 of the barbiturate molecule. By using an on-line photoreactor in HPLC analysis, barbiturates can be analyzed with much higher specificity in biological samples and, using absorbance ratios, identification of these drugs in unknown samples is facilitated.