Determination of inorganic plasma sulfate by indirect atomic absorption spectrophotometry

An indirect method for the determination of inorganic sulfate in small plasma volumes is presented. After removal of protein and phosphate by uranylacetate, sulfate is precipitated by barium chloride. Excess barium in the supernatant is measured by atomic absorption spectrophotometry. The sulfate content of the sample corresponds to the difference of the added and the measured barium. The mean concentration of inorganic plasma sulfate of healthy children, determined by this method, was 0.241 +/- 0.059 mmol/l.