Gas-phase ion association provides increased selectivity and sensitivity for measuring perchlorate by mass spectrometry.

Perchlorate (ClO4-) competitively inhibits the uptake of iodide by the thyroid gland. Trace quantities of perchlorate are being increasingly detected in food and environmental samples. There is great concern that perchlorate contamination may be far more widespread than believed until now.

Chemiluminometric measurement of atmospheric ozone with photoactivated chromotropic acid.

A highly sensitive, robust, fast, affordable measurement system based on interfacial gas-liquid chemiluminescence (CL) on a wetted transparent screen directly on top of a miniature photomultiplier tube provides the basis of an attractive method for ozone (O(3)). Alkaline chromotropic acid (CA, 4,5-dihydroxynaphthalene-2,7-disulfonic acid) chemiluminesces upon exposure to ozone. No light emission is observed from exposure of alkaline CA to NO(2) or H(2)O(2).