Elemental sulfur in sediments: analytical problems.

In the paper, a modified method for elemental sulfur (S8) determining using gas chromatography coupled with mass spectrometry (GC-MS) is proposed with estimation of selected validation parameters. The aim of this work was a review of problems associated with the determination of S8 and selection of the most optimal conditions for S8 analysis with GC-MS. The presented studies have shown that the temperature of the injector and the chromatographic column during S8 determination should not exceed 180 °C. At temperatures over 180 °C, the sulfur S8 is decomposed to the other sulfur species such as S2, S3, S4, S5, and S6. During decreasing injector and column temperature below 180 °C the chromatographic peak eluted as S8 is badly extended and asymmetric. To minimize the problems of S8 decomposition to other sulfur species during chromatographic process also other parameters of the GC-MS have been selected. In order to apply the proposed method for real sediments samples, determination of sulfur S8 in bottom sediments, collected in the Gulf of Gdansk (southern Baltic Sea), has been performed. The concentration of S8 fell in the range from below the limit of detection to 0.1432 ± 0.0095 mg/g d.w. The research has also shown that addition of approx. 200 mg of activated copper is effective for removing sulfur from bottom sediment extracts.