Determination of arsenic compounds in human urine by HPLC-ICP-MS

Abstract

Humans are unavoidably exposed to the arsenic compounds present in drinking water, in food items, and sometimes in respirable particles. Normally, the daily dose of total arsenic in the range of 10 to 50μg appears to be no threat to human health. However, in geographically limited regions Taiwan, India, Argentina, Chile) the concentrations of arsenic in drinking water and perhaps in food are elevated leading to excessive intake of arsenic and to arsenic-related health problems. Humans are exposed to inorganic arsenic compounds (arsenite, arsenate) and organic arsenic compounds methylarsonic acid, dimethylarsinic acid, arsenobetaine, arsenic-containing riboses, arsenolipids). These compounds are processed in the body quite differently. Arsenate might be reduced to arsenite, arsenite might be methylated to methylarsonic acid, and methylarsonic acid reduced and then methylated to dimethylarsinic acid. All of these compounds can be eliminated in the urine. Non-eliminated, trivalent compounds, such as arsenite and methylated compounds with trivalent arsenic, can interfere with biochemically important processes through reactions with thiol groups present, for instance, in enzymes. Information about the nature and the concentration of arsenic compounds excreted in the urine can be used to deduce exposure, gain insight into the chemical transformations of the arsenic compounds in the body, and estimate the methylating capacity of exposed persons.