Natural chlorate in the environment: Application of a new IC-ESI/MS/MS method with a Cl18O3- internal standard

Environmental Science & Technology
By: , and 



A new ion chromatography electrospray tandem mass spectrometry (IC-ESI/MS/MS) method has been developed for quantification and confirmation of chlorate (ClO3) in environmental samples. The method involves the electro-chemical generation of isotopically labeled chlorate internal standard (Cl18O3) using 18O water (H218O). The standard was added to all samples prior to analysis thereby minimizing the matrix effects that are associated with common ions without the need for expensive sample pretreatments. The method detection limit (MDL) for ClO3 was 2 ng L−1 for a 1 mL volume sample injection. The proposed method was successfully applied to analyze ClO3 in difficult environmental samples including soil and plant leachates. The IC-ESI/MS/MS method described here was also compared to established EPA method 317.0 for ClO3 analysis. Samples collected from a variety of environments previously shown to contain natural perchlorate (ClO4) occurrence were analyzed using the proposed method and ClO3 was found to co-occur with ClO4 at concentrations ranging from <2 ng L−1 in precipitation from Texas and Puerto Rico to >500 mg kg−1 in caliche salt deposits from the Atacama Desert in Chile. Relatively low concentrations of ClO3 in some natural groundwater samples (<0.1 μg L−1) analyzed in this work may indicate lower stability when compared to ClO4 in the subsurface. The high concentrations of ClO3 in caliches and soils (3−6 orders of magnitude greater) as compared to precipitation samples indicate that ClO3, like ClO4, may be atmospherically produced and deposited, then concentrated in dry soils, and is possibly a minor component in the biogeochemical cycle of chlorine.

Publication type Article
Publication Subtype Journal Article
Title Natural chlorate in the environment: Application of a new IC-ESI/MS/MS method with a Cl18O3- internal standard
Series title Environmental Science & Technology
DOI 10.1021/es1024228
Volume 44
Issue 22
Year Published 2010
Language English
Publisher ACS Publications
Publisher location Washington, D.C.
Contributing office(s) Nevada Water Science Center, Toxic Substances Hydrology Program
Description 6 p.
First page 8429
Last page 8434
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