You are here:
DEVELOPMENT OF ULTRATRACE LASER SPECTROMETRY TECHNIQUES FOR MEASUREMENTS OF ARSENIC
Citation:
Simeonsson, J. B., S. A. Elwood, M. Ezer, H. L. Pacquette, D. J. Swart, H. D. Beach, AND D J. Thomas. DEVELOPMENT OF ULTRATRACE LASER SPECTROMETRY TECHNIQUES FOR MEASUREMENTS OF ARSENIC. TALANTA. Elsevier Science BV, Amsterdam, Netherlands, 58(189-199), (2002).
Description:
Development of Arsenic Speciation Techniques Based on High Performance Liquid Chromatography and Atomic Fluorescence Spectrometry
J.B. Simeonsson, H.D. Beach and D.J. Thomas
US EPA, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Pharmacokinetics Branch, Research Triangle Park, NC 27711
Email simeonsson.joe@epa.gov
Phone 919 541 4430 FAX 919 541 5394
There is considerable interest in monitoring the speciation of arsenic in humans in order to investigate the relationships of specific arsenic compounds to cancers and other diseases. An important means of assessing environmental exposures to arsenic and characterizing the chemical distribution arsenic is through the measurement of urinary arsenic species, which include arsenite, arsenate, dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA).
The primary goal of the current study is to develop an analytical method for assessing arsenic distributions in human urine and blood or serum samples. The overall method is based on separation by high performance liquid chromatography combined with hydride generation- atomic fluorescence spectrometric (HGAFS) detection. Emphasis is being placed on developing an analytical method that minimizes the time of analysis while maintaining the resolution and quantitative recovery of individual arsenic species. To this point, method development has focused on the analysis of arsenic in urine samples.
Separation of arsenic species by reversed phase and ion exchange methods has been investigated. Reversed phase separation is performed using a 150 mm octadecylsilane column and a 5mM tetrabutylammonium hydroxide mobile phase buffered to pH = 6.2. Separation by ion exchange is performed using a 250 mm anion exchange column and a 30 mM potassium phosphate mobile phase buffered to pH = 4.5. Following separation, the eluted arsenic species are combined on-line with a 5% hydrochloric acid solution and then reacted with a 2% sodium borohydride solution to reduce the arsenicals to their corresponding hydrides for detection by flame atomic fluorescence spectrometry.
The results of the studies indicate that the ion chromatography approach provides effective separation of all four species within approximately 10 min. Using 94 microliter sample volumes, low parts-per-billion (ppb) measurements of the four arsenicals spiked in undiluted urine are possible. Method validation is being performed using reference materials, including a urine standard having certified values for total arsenic, DMA and arsenobetaine (NIES CRM No. 18 Human Urine, National Institute for Environmental Studies, Ibaraki, Japan) . Measurements of the reference material indicate a DMA concentration of 36 +/- 4 ppb, which is in excellent agreement with the certified value of 36 +/- 9 ppb. The application of the method to the assessment of environmental arsenic exposures via drinking water and foods is underway.
Note-This abstract does not necessarily reflect the views and policies of the US Environmental Protection Agency.