STUDIES ON THE QUANTITATIVE AUTORADIOGRAPHY .4. QUANTITATIVE RELIABILITY OF TLC-AUTORADIOLUMINOGRAPHY

Phosphor Imaging plates (IPs) with high sensitivity to both low- and h igh-energy radiation have been on the market since 1988. The TLC-autor adioluminography (ARLG) method was developed utilizing such IPs. The c onventional TLC method was suited for discrimination of microradioacti ve components; however, the method could only present semi-quantitativ e values. Conversely, the TLC-ARLG method showed completely quantitati ve values. That is, the TLC-ARLG method could be used to measure the r adioactivity ratio between C-14-radiolabeled spots A and B, which were spotted 1 mm apart on a TLC plate, after development with chromatogra m, not only when the radioactivity ratio between spots A and B was 1:1 , but even when it was 16:1, within the measurement error of +/-10%. T he ARLG method showed sensitivity, resolution, and quantitative reliab ility far superior to those of the scraping-liquid scintillation count er (LSC) method or radiochromatoscanner method. In the future, the ARL G method will be widely used as a quantitative microanalytical method for unknown radioactive metabolites existing as microcomponents in org anisms, especially for quantitative analysis considering mass balance to dose in biological samples, which is considered to be an important point in pharmacokinetic research.