DEVICE FOR ISOLATION AND PRECONCENTRATION OF VOLATILE ORGANIC-COMPOUNDS BY MEANS OF PURGING AND CRYOTRAPPING OF ANALYTES

A laboratory prototype of a device for the isolation of volatile organ ic compounds from Liquid samples, by means of purging followed by cryo genic preconcentration before introducing the analytes in a narrow ban d into a chromatographic column, has been presented. The device was te sted using a liquid solution of nine volatile hydrocarbons (n-hexane, n-heptane, n-octane, n-nonane, benzene, toluene, p- and o-xylenes and ethylbenzene) at the ppb (2.5-10) level. The automation of the whole p rocedure allows good repeatability of the results. Standard deviations of the slopes of calibration curves do not exceed 5% in any case and high values of regression coefficients confirm linearity. Different ty pes of real samples leg, rain water, sea water, wastewater) have been analysed using this device. The construction of this device allows an extension of the applicability of the analysis of a liquid sample by m eans of the purge and trap technique.