A derivatization approach using pyrylium salts for the sensitive and simple determination of sulfide in spring water by high performance liquid chromatography

A high-performance liquid chromatography method based on pre-column derivatization with the pyrylium salts (4-[p-(N,N-dimethylamino)phenyl]-2,6-diphenylpyrylium perchlorate (LN1) and 2,4,6-triphenylpyrylium tetrafluoroborate (L1)) has been developed for the determination of sulfide. After the reaction of sulfide ions with LN1 or L1 aiming at the formation of the corresponding thiopyrylium derivatives LN3 or L3, they were separated on a C18 column using phosphate buffer and acetonitrile as eluent, and afterwards detected with a UV/vis detector. By using the described method, sulfide ions can be determined in the range of 5.12-486.4 μg. L−1 or 1.024-20.48 μg. L−1 by means of L1 or LN1, respectively. In our experiments, the relative standard deviation was not higher than 2% and the recovery coefficient was in the range of 88-102%. The proposed method was applied to the determination of sulfide in spring water samples from Busko Zdrój and Uniejów health resorts located in Poland.