HEADSPACE SOLID-PHASE MICROEXTRACTION VERSUS PURGE-AND-TRAP FOR THE DETERMINATION OF SUBSTITUTED BENZENE COMPOUNDS IN WATER

Headspace solid-phase microextraction (SPME) is compared with purge and trap for the analysis of benzene, toluene, ethylbenzene, and the xylenes (BTEX) in water. A three-factor, two-level statistical design is used to optimize conditions for headspace SPME with respect to temperature, pH, and salt addition. Best sensitivity is achieved at ambient temperature with NaCI saturation; pH is not a factor. Multiple samples ranging in concentration from 4 to 140 parts per billion are analyzed by both methods. The comparison is expressed by plotting the results and calculating unweighted regression lines. A consistent correlation is established between the two methods for all compounds. Statistical method detection limits (MDLs) are determined for BTEX by headspace SPME and are compared with MDLs required by two North American regulatory agencies. © 1994, Oxford University Press. All rights reserved.