Ion chromatographic determination of thiosulfate in oil shale leachates

Thiosulfate ions, S/sub 2/O/sub 3//sup 2 -/, were determined by ion chromatography (IC) on a standard 3 x 250 mm anion separator column (Dionex No. 30827) using 7.2 M Na/sub 2/CO/sub 3/ plus 9.0 mM NaHCO/sub 3/ eluants. Unsatisfactory peaks were obtained and the lifetime between suppressor columns (6 x 250 mM) regeneration was drastically reduced. However, when this procedure was repeated using a portion of the resin from a damaged 3 x 150 mM anion concentrator precolumn (Dionex 30825) which was repacked to produce a 3 x 75 mM column and which was installed to serve as the separator column, and by using the standard 2.4 mM Na/sub 2/CO/sub 3/ plus 3.0 mM NaHCO/sub 3/ eluants and a high flow rate (275 mL/h), S/sub 2/O/sub 3//sup 2 -/ was eluted in about four minutes. The other major anions present in retorted oil shale leachates, eluted in less than 2 min as a single peak. Resolution from S/sub 2/O/sub 3//sup 2 -/ was excellent except for a few samples containing extremely high SO/sub 4//sup 2 -/ concentrations. (ATT)