Arsenic is a trace element found in the earth’s crust at an average concentration of ∼5 μg/g, which is ranked about 54th in relative abundance. Arsenic is a component of 245 minerals, associated most frequently with other metals, such as copper, gold, lead, and zinc, in sulfidic ores. Many arsenic species undergo (bio)transformation, and the toxicities of the various arsenic species vary by several orders of magnitude. Our first objective is to determine arsenic speciation, and we focus on the method of high performance liquid chromatography (HPLC) separation and simultaneous detection with both inductively coupled plasma mass spectrometry (ICPMS) and electrospray ionization tandem mass spectrometry (ESI-MS/MS). This methodology enables identification and quantitation of individual arsenic species present in various environmental media.
Arsenic is one of the most important environmental agents causing chronic human disease. A wide variety of adverse health effects, including bladder, lung, and skin cancers, and many non-cancerous effects, have been attributed to chronic exposure to arsenic. The mechanisms of arsenic toxicity are complicated and not fully understood. The trivalent arsenic species have high affinity with free sulfhydryl groups in proteins. Arsenic binding to a specific site of the protein could alter the conformation and function of the protein as well as its recruitment of and interaction with other functional proteins. We summarize various aspects of arsenic binding to proteins, demonstrate analytical techniques for the characterization of arsenic binding, and discuss the chemical basis, biological implications, and consequences of arsenic binding to proteins.