Measurement of Henry coefficients by capillary columns coated with slightly polar solvents

The specific retention volumes and Henry coefficients measured on packed co lumns are compared with those calculated via retention indices determined o n wall coated open tubular capillary columns. The stationary phase liquids used were derivatives of a branched paraffin, C78H158, where a methyl or et hyl group of the paraffin was replaced by OH, CN, OCH3 and SH groups. The r etention indices of a series of molecular probes of varying polarity (aroma tics, 1-chloroalkanes, 1-acetoxy-alkanes, 1-alkanols, 2-alkanones) were det ermined at T = 403.15 K on fused-silica open tubular columns prepared by st atic coating that gave stable and uniform solvent films. After obtaining th e absolute data on packed columns for n-alkanes, the specific retention vol umes and Henry coefficients of the solutes were calculated. The retention d ata obtained on both columns showed good agreement.