A method to test the detectability of GC/PFPD for an extended concentration range with respect to reduced sulfur compounds

摘要

In this study, a possible means to extensively expand the quantifiable range of reduced sulfur compounds (RSC) in air has been investigated by a combined application of GC with pulsed flame photometric detector (PFPD) and a multifunction thermal desorber (TD) system. To comply with the purpose of this study, gaseous RSC standards containing the equimolar concentrations of H2S, CH3SH, DMS, DMDS, and CS, were prepared at 11 concentration levels (i.e., 10 ppb - 10 ppm (over 103 range)). These standards were then used to derive three-point calibrations based on the modified injection through a TD (MITD). If the mean calibration slopes of each concentration level are normalized to that of CH3SH, the relative ordering is found as 0.65 (H2S): 1 (CH3SH): 1.34 (DMS): 2.24 (DMDS). The reproducibility of MITI) method, when assessed in terms of relative standard error (RSE) for all calibration slopes, had the most stable pattern for DMDS (5.77%) and the least stable one for H2S (12.8%). The sensitivity of the MITD-based calibration generally improved with an increase in concentration levels of standard gas. Based on our study, the MITI) technique is useful to extend quantification of GC/PFPD by allowing RSC detection over a 10(3) range.