Boron in drinking-water
Background document for development of WHO Guidelines for Drinking-water Quality
Analytical methods
A spectrometric method using azomethine-H is available for the determination of borate in water. The method is applicable to the determination of borate at concentrations between 0.01 and 1 mg/litre. The working range may be extended by dilution (ISO, 1990).
A widely used method for the analysis of boron in bone, plasma, and food is inductively coupled plasma atomic emission spectroscopy (Hunt, 1989). This method is also used for water (ISO, 1996) and wastewater (Huber, 1982). Detection limits in water range from 6 to 10 µg of boron per litre.
Inductively coupled plasma mass spectroscopy (ICP-MS) is a widely used non-spectrophotometric method for the analysis of boron, as it uses small volumes of sample, is fast, and applies to a wide range of materials (fresh and saline water, sewage, wastewater, soils, plant samples, and biological materials). ICP-MS can detect boron down to 0.15 µg/litre (WHO, in press). Using direct nebulization, ICP-MS can give a detection limit of 1 ng/g in human blood, human serum, orchard leaves, and total diet (Smith et al., 1991).