Perchlorate, a potentially significant threat to human health, is probably pervasive in the environment, albeit at extremely low concentrations. Efforts to understand the origins and behavior of environmental perchlorate depend critically on the ability to measure its concentrations accurately in a variety of environmental sample matrices. Perchlorate concentrations in polar snow and ice core samples have been estimated to be as low as 0.1 ng L–1. Liquid chromatography and tandem mass spectrometry (MS/MS) with electrospray ionization (ESI) has been successfully utilized for perchlorate determination at the low parts-per-trillion (ng L–1) level. We interfaced an ion chromatography system with an ESI-MS/MS (AB Sciex QTRAP 5500) for the rapid and accurate determination of perchlorate at the sub-ng L–1 level in ice core samples without pre-concentration. Using optimized instrumental parameters, limit of detection and lower limit of quantification of 0.1 ng L–1 and 0.3 ng L–1, respectively, have been achieved and maintained with careful instrument upkeep. A linear dynamic range of 0.3 – 10.0 ng L-1 has been utilized for routine ice core analysis, although larger ranges can be established for higher concentrations. This new analytical method is enabling us to reconstruct a long (more than 300 years) record of perchlorate in the environment from the analysis of ice cores from Greenland in the Arctic. Such records will be very useful to the identification and quantitative assessment of natural and anthropogenic contributions to perchlorate in the current environment.

Determination of perchlorate in polar ice cores down to sub-ng L-1 level using ion chromatography-tandem mass spectrometry

249th National Meeting (2015)

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