Arsenic is a toxic element, and the toxicity of the element is dependent upon the molecular form it is in. Accurate assessments of arsenic exposure require the measurement of a complete panel of inorganic, organic, and metabolite As species in urine, including arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), trimethylarsine oxide (TMAO), arsenobetaine (AB), and arsenocholine (AC). A certified reference material (CRM) containing the panel of As species in urine is sorely needed for method validation and quality assurance of assessment measurements. Until now, such a CRM was unavailable, due in part to the difficulty in stabilizing As species, especially AsIII. For the first time, O2 in the ambient atmosphere was determined to be the primary cause for the instability of AsIII, and a procedure was developed to stabilize the panel of As species in a dark, low temperature (< -70 °C), and oxygen-free environment. A new Standard Reference Material® (SRM) 2669 Arsenic Species in Frozen Human Urine has been developed to meet the needs in arsenic exposure measurements in general and in National Health and Nutrition Examination Survey (NHANES) in particular. SRM 2669 is certified for each aforementioned As species at two levels that proximate the 50th percentile and 95th percentile distribution in US population. The SRM was jointly produced by the National Institute of Standards and Technology (NIST) and the Centers for Disease Control and Prevention (CDC). Measurements leading to the certification were made collaboratively at NIST, CDC, and the State University of New Jersey.
Citation: Analytical Chemistry
Pub Type: Journals
arsenic species, frozen, urine, certified reference material, oxygen absorber