On-line measurement of perchlorate in atmospheric aerosol based on ion chromatograph coupled with particle collector and post-column concentrator

An automated analysis system has been developed for measuring perchlorate concentration in atmospheric aerosol. The perchlorate in aerosol sample, which has been collected with water mist in a hydrophobic filter/mist chamber based particle collector, is continuously preconcentrated. The matrix ions such as sulfate are subsequently removed from the preconcentrator. The remaining perchlorate is then analyzed on-line with an ion chromatograph in conjunction with a Nafion membrane tube based post-column concentrator. The sensitivity is increased by a factor of 7.7 with the post-column concentration technique. The proposed system has been successfully operated at Tokushima, Japan. The limit of detection is 0.35 ng/m3 for 3 h sampling cycle. The perchlorate concentration in the atmospheric aerosol averaged 1.01±1.75 ng/m3 (n=12).