Rapid analysis of volatile arsenic species released from lake sediment by a packed cotton column coupled with atomic fluorescence spectrometry

Abstract

It is very important to qualify and quantify volatile arsenic species produced by sediment in order to further understand transformation and transportation of arsenic. Effective separation and sensitive detection of various volatile arsenic species are definitely the key steps for that. In this paper, a short packed cotton column was found effective to separate volatile arsenicals (AsH₃, CH₃AsH₂, (CH₃)₂AsH and (CH₃)₃As) rapidly. Based on this, a new online system for collection and speciation of volatile arsenic species was developed. After successful separation on a cotton column, volatile arsenic species were sensitively detected by atomic fluorescence spectrometry (AFS). A special PTFE chamber was designed and applied for both incubation and collection of volatile arsenicals generated from sediment online. Minor amounts of volatile arsenicals produced from sediment in headspace were sensitively measured. Real sample analysis and a spiking experiment indicated that the established system was sensitive and practical for the analysis of volatile arsenicals produced in the environment. It will be a very useful tool for further understanding the transformation of arsenic in the environment with low instrumental costs and running fees.