Determination of boron in fresh and saline waters by inductively coupled plasma mass spectrometry

Abstract

Boron in fresh and saline waters was determined by inductively coupled plasma mass spectrometry (ICP-MS). The presence of concomitant elements in solution complicated the determination of this element. Excess of dissolved solids caused loss of analytical sensitivity and a matrix-induced mass discrimination effect, resulting in analytical error. The use of cation exchange was effective in removing dissolved salts and permitted the accurate determination of boron by ICP-MS. The accuracy and precision for the determination of boron using three calibration strategies, external calibration, the method of standard additions and isotope dilution, are compared. For the determination of boron in synthetic water and brine solutions, the isotope dilution procedure produced more accurate results than did the other calibration strategies. The method was applied to the determination of boron in a series of reference waters available from the National Research Council of Canada and a synthetic National Institute of Standards and Technology fresh water sample. Boron was determined with a precision of 3% at the detection limit of 0.15 p.p.b. and a precision of 1% at higher concentrations.