MultiSimplex optimisation of purge-and-trap

Abstract

Purge-and-trap extraction and GC-FID determination of the nine volatile organic compounds benzene, toluene, chlorobenzene, ethylbenzene, m-xylene, o-xylene, 1,3-dichlorobenzene, 1,4-dichlorobenzene and 1,2-dichlorobenzene from soil samples were optimised by making use of the simplex method implemented in the MultiSimplex computer program. The experimental variables studied were the sample heating time and temperature, the purge time, the concentration of sodium chloride and the cooling temperature of the trap. Optimum conditions obtained were 7.8 min purge after sample heating at 83 °C for 8.4 min, a sodium chloride solution of 0.04 mol.1⁻¹ and the trap at ambient temperature. The extraction yield was tested by means of repeated analyses of different samples, obtaining recoveries ranging between 61 and 83% and relative standard deviations between 7 and 16%.