EVALUATION OF AN ELECTROTHERMAL VAPORIZATION SAMPLE INTRODUCTION SYSTEM INTO A STABILIZED CAPACITIVELY COUPLED HE-PLASMA (SCP) FOR THE DETERMINATION OF CHLORINE

This paper describes the coupling of a graphite furnace (Perkin Elmer, HGA 500) as a sample introduction system to the element specific dete ctor (ESD) for atomic emission measurements of chlorine. The ESD consi sts of the stabilized capacitive plasma (SCP), a 27 MHz discharge in h elium at atmospheric pressure, a fiber optics link and an interference filter spectrometer. The analytical feasibility of this system was te sted for the determination of chlorides in aqueous solutions and sever al chlorinated organic compounds in methanol. To overcome the problems of varying sensitivities with different counter cations a matrix matc hing procedure for aqueous samples has been developed by using cation exchanging resin in the Li+-form. The detection limit of Cl- at 837.6 nm is 5 ng and the precision at the 25 mu g ml(-1) level is 3.2%. The proposed procedure has been tested for chloride determination in real water samples and a very good correspondence to the results with those obtained by ion chromatography is reported. Several chlorinated organ ic compounds were determined by direct introduction into the plasma wi thout a desolvation step. One randomly selected substance (i.e. atrazi ne) was used as reference for the calibration of 10 other organic anal ytes.