IMPROVED IDENTIFICATION BY IN SITU UV SPECTRA IN PLANAR CHROMATOGRAPHY

Abstract

Novel software was introduced for library searching in planar chromatography, based on corrected Rf values (hRf c), in situ ultraviolet (UV) spectral correlation, and spectrum maximum site comparison. Analysis of autopsy urine samples by thin-layer chromatography (TLC) and overpressured layer chromatography (OPLC) revealed that the new method was superior to the standard method using hRf c and correlation only. The advantage was more pronounced in TLC, which possessed poorer separation power and generally lower quality spectra than OPLC. In 11 cases of 47 in TLC, the hit list position of the correct finding was improved by the new method. This result indicates that the spectrum maximum site function gives a different kind of discrimination than would be obtained by only setting the correlation cut-off at a higher value. In OPLC, the hit lists were originally shorter, but an improvement in the list lengths was evident. OPLC proved to be the planar method of choice in the screening analysis of urine samples for drugs due to its high separation power and speed.