A sensitive method for atmospheric sulfur dioxide determination by reaction cell inductively coupled plasma mass spectrometer

A sensitive method for sulfur dioxide (SO2) determination was developed
with a reaction cell inductively coupled plasma mass spectrometer (ICP-MS)
by preconcentrating SO2 from gas samples in solutions. O2 flow rate was
set at 0.7 mL min-1 for optimal S/N ratio at m/z 48 (32S16O+). Favorable
conditions to prepare SO2 concentrated solutions, including sampling flow
rate, the volume of concentrated solution, the number of perfluoroalkoxy
alkane (PFA) bubble absorption bottles, and the composition of
concentrated solution, were investigated using SO2 in nitrogen gas
reference materials within the range of 5.00 parts per billion (ppb) to
1.00 parts per million (ppm). A limit of detection (LOD) of 0.11 ppb was
achieved, corresponding to 100 L 5.00 ppb SO2 with a sampling flow rate of
0.5 L min-1. This method also showed favorable selectivity in the assay of
atmospheric SO2 level, providing its promising further application in
monitoring gaseous environmental pollutants.