Elemental Analysis

Abstract

Ball et al. [1] have described a method for determining down to 20 µg/l boron in estuarine waters. A dc argon plasma emission spectrometer was used. Quenching of the plasma by high solute concentrations of easily ionised elements such as alkali metals, as well as high and variable electron density, may be avoided by dilution. The method was found to be more sensitive, equally precise, less subject to interference and with a wider linear analytical range than the carmine spectrophotometric method. Very few interferences were noted when this technique was tested. There is a minor interference from the differential enhancement of tungsten relative to boron in solutions containing high concentrations of alkali metals. The effect of this is to increase the background when estuary water is being analysed, and it can be mitigated by using synthetic estuary water as a blank, by dilution, or by analysis by the method of standard additions.An oscillopolarographic method gave a detection limit of 3 ×10 -9 mol/dm -3 and a linear range of 3 ×10 -9 to 7 ×10 -7 mol/dm -3 in the determination of boron in seawater.Traces of boron in seawater have been determined by flow injection analysis with spectrophotometric detection at 415 nm using G 30 methine H. The linear range was 1-10 mg/l boron with a detection limit of 0.017 mg/l [3]. Total IodineSchnepfe [4] has described a method for the determination of total iodine and iodate in seawater. One per cent aqueous sulfamic acid (1 ml) is added to seawater (10 ml), then it is filtered, if necessary, and the pH adjusted to 2. After 15 min, 1 ml 0.1 M sodium hydroxide and 0.5 ml 0.1 M potassium permanganate are added and the steam bath heated for 1 h. The cooled solution is filtered, the residue washed, the filtrate plus washings is diluted to 16 ml and 1 ml of a 0.25 M phosphate solution (containing 0.3 µg iodine as IO -3 per