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.

A continuous analyzer for soluble anionic constituents and ammonium in atmospheric particulate matter.

A new continuous soluble particle collector (PC) that does not use steam is described. Preceded by a denuder and interfaced with an ion chromatograph, this compact collector (3 in. o.

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).

Field measurement of acid gases and soluble anions in atmospheric particulate matter using a parallel plate wet denuder and an alternating filter-based automated analysis system.

We present a new fully automated instrument for the measurement of acid gases and soluble anionic constituents of atmospheric particulate matter. The instrument operates in two independent parallel channels. In one channel, a wet denuder collects soluble acid gases; these are analyzed by anion chromatography (IC).