BLUEPRINTS OF AN AUTOMATIC ZONAL SCRAPER AND SAMPLE COLLECTOR FOR RADIO ASSAY OF THIN-LAYER CHROMATOGRAMS

摘要

Zonal radioscanning of thin-layer chromatoplates using a specially designed manual scraper (1, 2, 3) capable of removing 1-, 2-, or 5-mm zones has been described. Liquid scintillation counting of the zones provides 4п counting geometry and efficiencies comparable to those observed for nonquenched liquid systems containing carbon-14 and tritium. Plotting the radioactivity of each adjacent zone as a continuum results in the distribution of activity according to its position on the thin-layer chromatography plate;when used in conjunction with photodensitometric quantitation of the unlabeled compounds, specific activities can readily be calculated. The high resolution obtainable with this scraper also makes its usefulness applicable outside the realm of radiometric analysis. The scraping of minute zones has indeed made it possible to monitor a chromatostrip in predetermined fractions;this is analogous to monitoring the mass and radioactivity of liquid and gas flow from columns. The manual scraper has served as the prototype for the construction of the completely automatic zonal scraper and sample collector described in this report.