QUANTITATION OF VOLATILE SULFUR-COMPOUNDS IN POLLUTED WATERS

A study on the linear dynamic range of a combined cryogenic trap-gas c hromatographic method with flame photometric detection (FPD) has shown that quantitation of volatile sulphur compounds (VSCs) in heavily pol luted waters, in the order of hundreds of nanograms, is possible. A co rrect calibration of the FPD is needed for this purpose. Calibration o ver 2.5-3 orders of magnitude requires the determination of three diff erent linear equations extending over this mass range. Equations for h ydrogen sulphide, carbonyl sulphide, methanethiol, dimethyl sulphide a nd carbon disulphide are given. The intervals corresponding to each li near equation are determined from the inflexion points in the calibrat ion plots. The changes in sign of the relative error resulting from re -calculation of the VSC mass after use of one single calibration curve for the whole mass range interval provide a secondary criterion of in terest. (C) 1997 Elsevier Science B.V.