GAS-SOLID RETENTION VOLUMES OF ORGANIC-COMPOUNDS ON STYRENE-DIVINYLBENZENE AND ETHYLVINYLBENZENE-DIVINYLBENZENE COPOLYMER SORBENT BEADS

Reliable gas sampling with a sorbent requires a good knowledge of the gas-solid retention volumes of the analytes on the sorbent. Literature data on specific retention volumes at 20 degrees C (V-g,V-293, 1/g) a re reviewed for a number of styrene-divinylbenzene (Sty-DVB) and ethyl vinylbenzene-divinylbenzene (EVB-DVB) sorbents, namely XAD-2, Porapak P, Porapak Q, Chromosorb 101, and Chromosorb 102. New measurements are also made by gas-solid chromatography for a Sty-DVB polymer employed in one variety of Empore membrane extraction filters. For all of the d ata, the log V-g,V-293 values are highly correlated with both log p(L) (0) (log of the liquid vapor pressure at 20 degrees C) and with T-b (p ure compound boiling point, K). The correlation equations allow the pr ediction of log V-g,V-293 based on either log p(L)(0) or T-b. Equation s that can be used for a wide range of compounds and a range of Sty-DV B and EVB-DVB sorbents are: log V-g,V-293=-1.16 log p(L)(0) + 3.51, an d log Vg,293 = 0.0227T(b) - 6.60. Separate equatins are recommended fo r aliphatic acids and alcohols. For the Sty-DVB beads used in one vari ety of Empore extraction filters, the correlation equations are log V- g,V-293 = - 0.99 log p(L)(0) + 3.04, and log V-g,V-293 = 0.0175T(b) - 4.97. Most of the available data support absorption into the resin mat rix as the dominant gas-solid partitioning mechanism for organic analy tes to Sty-DVB sorbent materials.