Abstract
Tandem quadrupole inductively coupled plasma mass spectrometry has the potential capability to measure (129)I at extremely low concentration if spectral interferences from (129)Xe and (127)I(1)H(2) can be eliminated effectively. Ozone was introduced as the reaction gas, resulting significantly improved reactions of ((129)I(+)→(129)I(16)O(+)) and ((129)I(+)→(129)I(16)O(2) (+)), and permitted the highly sensitive measurement of (129)I(+) as (129)I(16)O(+) and (129)I(16)O(2) (+), helping eliminate spectral interferences related to (129)Xe(+) and (127)I(1)H(2) (+). In isotopic ratio ((129)I/(127)I) analysis by measuring ((129)I(+)→(129)I(16)O(2) (+))/((127)I(+)→(127)I(16)O(2) (+)), a blank ratio of 6.7 × 10(-10) can be realized for a solution of 500 μg/mL natural iodine, improved by one order of magnitude than the best performance previous reported. This technique contributes to the measurement of trace level (129)I, a radionuclide of iodine attracting attentions as a geochemical tracer related to the development and civilian use of nuclear energy as well as a regulated radionuclide with guidance levels in drinking water established by the World Health Organization.