Abstract
The measurement of iodine in natural-water samples by inductively coupled plasma mass spectrometry (ICP-MS) is described. The limit of detection is 10pg/ml. The element is easily determined by this method without separation or preconcentration. Because iodine is highly volatile, the obtained signal is somewhat unstable. Iodine vaporization, however, can be restrained by the addition of an organic alkali (for example tetramethyl ammonium hydroxide), making it possible to obtain a stable signal. Analytical results using the conventional calibration-curve method and the standard addition method agreed well. We determined the iodine concentration of 42 natural-water samples in the northern Kanto area. The concentrations of iodine ranged from 0.65 to 35.9ng/ml.
