More On Arsenic

We read with interest the C&EN coverage of a recent report in Science of a bacterium that thrives in an arsenic environment and the subsequent controversy regarding claims of arsenic replacing phosphorus in the organism’s DNA (C&EN, Dec. 6, 2010, page 36, and Dec. 13, 2010, page 7). We agree with the tone of the C&EN article suggesting that a deeper look is required before such claims can be justified. We also point out that HPLC-ICP-MS (see, for example, Anal. Chem., DOI: 10.1021/ac051679y) is a relatively straightforward analytical technique that offers the ability to determine the level of arsenic (or any other metal) within the eluted peaks of an HPLC chromatogram—an approach that would quickly settle the question of whether or not arsenic has become incorporated into the DNA of these bacteria.

Xiaodong Bu, Tiebang Wang, Qiang Tu, and Chris Welch
Rahway, N.J.