Abstract

In this study, temporal stability of 5 reduced sulfur compounds (RSCs) including (H_2S, CH_3SH, DMS,CS_2, and DMDS) was investigated up to 30 days. To learn the temporal changes in RSC concentration levels,two types of long-term storage experiment were carried out by employing two different approaches for sample storing in Tedlar bag samplers. The first one named as a forward (F) storage method consists of preparing all samples in the beginning of experiment. All these samples were analyzed sequentially through time. The second approach named as a reversed (R) storage method was carried out by preparing each sample through time and by analyzing all of them in the last day. For these experiments, RSC standards were prepared at 10 ppb in 10 L Tedlar bag. The results of both methods were consistent enough to show a tendency of the concentration reduction through time. Moreover, the lightest RSC, H_2S showed the most significant reduction of 84.8% at the end of experiment. To validate difference between these results, t-test was applied to the data obtained between the two methods at 90% significance level. According to t-test, the results of the two approaches were greatly distinguished from 3 RSCs (H_2S, CH_3SH, and DMDS). The results also indicated that the temporal reduction of RSC differs greatly between light (H_2S and CH_3SH) and heavy RSCs (DMS, DMDS, and CS_2). The former generally exhibited much significant reduction through time due probably to their lower stability.