The effect of interfering ions has been investigated.
The presence of phosphate, silicate, hydrogencarbonate, sulfate, iodide and bromide are tolerable when
present in concentrations up to 100 mg ml−1, about a
250 fold excess. Magnesium, calcium, strontium, barium
cobalt, nickel, copper, zinc and cadmium are also
tolerable up to 100 mg ml−1 in the presence of EDTA.
Iron is only tolerable up to 50 mg ml−1 in the presence
of tartrate (Table 2)