The determination of sulphate in natural waters by inductively-coupled plasma emission spectrometry

Sulphate is determined simultaneously with other constituents by using inductively-coupled plasma emission spectrometry; the intensity of the 180.73-nm sulphur line is monitored. At a forward power of 1100 W, under compromise conditions, a 3 s detection limit of 0.08 mg l^-1 sulphate and a precision of 0.8% RSD at the 200 mg l^-1 sulphate level were obtained. A small spectral interference from calcium is overcome by software corrections, and good agreement is demonstrated between the proposed method and spectrophotometric sulphate measurements for a variety of natural waters including seawater.