Determination of trace level of perchlorate in Antarctic snow and ice by ion chromatography coupled with tandem mass spectrometry using an automated sample on-line preconcentration method

A new ion chromatography coupled with tandem mass spectrometry (IC-ESI-MS/MS) method, with automated sampling and on-line preconcentration, has been developed for the determination of perchlorate in Antarctic snow and ice at low part-per-trillion (ng/L) levels. To the best of our knowledge, this is the first time that an analytical method is used for the determination of perchlorate in Antarctic snow and ice. The IC-ESI-MS/MS instrumentation consisted of an ICS2000 ion chromatography (IC) system coupled to an API3200 electrospray tandem mass spectrometer (ESI-MS/MS). On-line preconcentration was realized through a six-port injector valve, a TAC-ULP1 concentrator column and an AS auto-sampler. Multiple reaction monitoring (MRM) mode was used to quantify the perchlorate anion. The transition of 35Cl16O4− (m/z 98.9) into 35Cl16O3− (m/z 82.9) was monitored for quantifying the main analyte, and the transition of 37Cl16O4− (m/z 100.9) into 37Cl16O3− (m/z 84.9) was monitored for examining a proper isotopic abundance ratio of 35Cl to 37Cl, which was used as a confirmation tool. The limit of detection (LOD) and limit of quantitation (LOQ) for the method was 0.2 ng/L and 0.5 ng/L, respectively. And this new method exhibited acceptable accuracy and precision for samples at ng/L levels. All the tested snow and ice samples were found to contain measurable amount of perchlorate, ranging from 10 ng/L to 340 ng/L.

With the newly developed analytical method, trace level perchlorate in Antarctic snow and ice was analyzed. This is the first time that perchlorate concentration in Antarctic snow and ice samples is reported.Figure optionsDownload as PowerPoint slide