AbstractThe effects of trapping temperature and column film thickness were investigated with respect to their ability to promote effective cryofocusing on fused silica capillary columns. The study was a further development of the purge and trap with whole column cryotrapping (P&T/WCC) method. The rates at which compounds could be thermally desorbed from a P&T unit and transferred to a column (with zero split) were first examined. A near quantitative transfer of the desorbable analytes was obtained with a 4 min, 180°C, 20 mL/min desorption. The compounds tested included naphthalene. Columns with film thicknesses from 0.12 to 3.0 μm were then investigated in P&T/WCC analyses with WCC temperatures ranging from −80 to 0°C. The trapping took place from a transfer line gas stream initially at 175°C. The volatilities of the compounds examined varied from that of 1,1‐dichloroethene to 1,1,2,2‐tetrachloroethane. A higher film thickness was found to ease the WCC temperature requirements. Within each column type, the warmest WCC temperatures which allowed good cryotrapping with no significant increases in peak width were: 0.25 μm, −70°C; 1.0 μm, −50°C; 3.0 μm, −20°C. In addition to being quantitative, the trapping provide