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

Determination of trace perchlorate in river water by ion chromatography with online matrix removal and sample concentration

This paper proposes a simple ion chromatographic approach to determine trace amounts of perchlorate in river water samples. Determination of the trace perchlorate by ion chromatography typically faces two challenges: interference by matrix ions such as chloride, nitrate, and sulfate in the samples and insufficient detection sensitivity. In the present study, online pretreatment of the samples with an OnGuard II Ba/Ag/H disposable sample pretreatment cartridge prevented the sulfate peak tailing from overlapping with the perchlorate peak on the chromatogram. In addition, the matrix removal enabled as large as 10 mL of sample to be loaded into a high exchange capacity anion concentrator, significantly improving perchlorate's detection sensitivity. The proposed approach achieved a detection limit (S/N = 3) of 0.046 µg L^-1 without using a costly mass spectrometer and successfully determined sub µg L^-1 levels of perchlorate in river water.

Occurrence, latitudinal gradient and potential sources of perchlorate in the atmosphere across the hemispheres (31°N to 80°S)

Perchlorate (ClO₄^-) is harmful to human health, and knowledge on the levels and sources of natural ClO₄^- in different environments remains rather limited. Here, we investigate ClO₄^- in aerosol samples collected along a cross-hemisphere ship cruise between China and Antarctica and on a traverse between coastal East Antarctica and the ice sheet summit (Dome Argus). Perchlorate concentrations range from a few to a few hundred pg m^-3. A clear latitudinal trend is found, with elevated ClO₄^- concentrations near populated areas and in the southern mid-high latitudes. Spatial patterns of atmospheric ClO₄^- over oceans near the landmasses support that terrestrial ClO₄^- is not transported efficiently over long distances. In the southern mid-latitudes, higher ClO₄^- concentrations in March than in November-December may be caused by significant stratospheric inputs in March. Perchlorate concentrations appear to be higher in the warm half than in the cold half of the year in the southern high latitudes, suggesting seasonal difference in main atmospheric sources. ClO₄^- may be formed in the reactions between chlorine free radical (Cl·) and ozone (O₃) in the stratosphere when Antarctic ozone hole occurs during September-October. And the stratosphere-produced ClO₄^- is moved to the boundary layer in several months and may be responsible for the high ClO₄^- concentrations in the warm half of the year. Perchlorate produced by photochemical reactions between O₃ and Cl· in the Antarctic stratosphere is likely responsible for the higher ClO₄^- concentrations in Antarctica than in Arctic.

Perchlorate occurrence in foodstuffs and water: Analytical methods and techniques for removal from water - A review

Perchlorate (ClO₄^-), a type of contaminant with high diffusivity and durability, has been widely detected in water and foodstuffs, arousing a global concern. It can interfere with normal function of the human thyroid gland, affecting human health. Therefore, determination of perchlorate in water and foodstuffs, and removal from water are important. This review focuses on the occurrence of perchlorate, mainly in water and foodstuffs, and provides an overview of analytical methods for determination of perchlorate over the last two decades. In addition, merits and drawbacks of the various methods have been considered. This review also highlights the most commonly used approaches for removal of perchlorate from water. Finally, current trends and future perspectives in determination of perchlorate and removal from water are proposed. This review provided a comprehensive understanding of perchlorate occurrence and its removal from water, and had practical significance in reducing the harm of perchlorate to human.