The Investigation of Unexpected Arsenic Compounds Observed in Routine Biological Monitoring Urinary Speciation Analysis

Abstract

This study investigates the identity of two unexpected arsenic species found separately in a number of urine samples sent to the Health and Safety Executive’s Health and Safety Laboratory for arsenic speciation (arsenobetaine, AB; arsenite, As3+; arsenate, As5+; monomethylarsonic acid, MMA5+; and dimethylarsinic acid, DMA5+). Micro liquid chromatography coupled to inductively coupled plasma mass spectrometry (µLC-ICP-MS) and electrospray time of flight tandem mass spectrometry (ESI-QqTOF-MS/MS) were used to identify the two arsenic peaks by comparison to several characterized arsenicals: arsenocholine, AC; trimethyl arsine oxide, TMAO; dimethylarsenoacetate, DMAA; dimethylarsenoethanol, DMAE; thio-dimethylarsinate, thio-DMA; thio-dimethylarsenoacetate, thio-DMAA and thio-dimethylarsenoethanol, thio-DMAE. The results from both the ICP-MS and ESI-QqTOF-MS/MS investigations indicate that the unexpected arsenic species termed peak 1 was thio-DMA. While the unexpected arsenic species termed peak 2 has yet to be identified, this investigation shows that it was not AC, TMAO, DMAA, DMAE, thio-DMA, thio-DMAA or thio-DMAE. This study demonstrates the incidence of unexpected arsenic species in both routine and non-routine urine samples from both workers and hospital patients.

Thioarsenite Detection and Implications for Arsenic Transport in Groundwater

“…Here, we focus on results obtained using the AS22 column with isocratic elution (60 mM NH 4 NO 3 ; Sigma-Aldrich, SigmaUltra) and the AS7 column eluted with a NH 4 NO 3 gradient (30–60 mM) at 25 °C and using a flow rate of 1 mL/min. Use of these columns to achieve arsenic species separation is documented in research examining natural water samples − and biological fluids. − Selection of NH 4 NO 3 as the mobile phase was based on its pH flexibility, column stripping potential, and plasma compatibility . To circumvent pH-related methodological artifacts, sample/eluent pH was matched within ±0.15 pH units by adding NH 4 OH (Sigma-Aldrich, ACS reagent) to the eluent (pH range: 5.5 to 9.0).…”

Effects of Dietary Intake of Arsenosugars and Other Organic Arsenic Species on Studies of Arsenic Methylation Efficiency in Humans

“…Liquid chromatography separation followed by simultaneous detection with both electrospray ionization mass spectrometry (ESIMS) and inductively coupled plasma mass spectrometry (ICPMS) provides complementary information for the identification and quantification of arsenic species. Unknown arsenic species at very low concentrations are still challenging to identify . Further research is needed to improve the efficiency of electrospray ionization of arsenic species present in complex sample matrixes, enhance resolution of separation and sensitivity of detection, develop new techniques, and refine existing techniques for arsenic speciation analysis.…”

“…Unknown arsenic species at very low concentrations are still challenging to identify. 104 Further research is needed to improve the efficiency of electrospray ionization of arsenic species present in complex sample matrixes, enhance resolution of separation and sensitivity of detection, develop new techniques, and refine existing techniques for arsenic speciation analysis.…”