Precipitation chemistry quality assurance

NAA is preferred for the analysis of unique samples such as meteorite, the certification of reference materials, and quality assurance in analytical chemistry [21]. Definitive methods are based on the activation of samples, selective separation of analyzed radionuclides by column (ion-exchange) chromatography, and measurement by gamma spectrometry [15, 16, 19]. In definitive methods, radiochemical separation, co-precipitation, extraction, and ionic exchange guarantee the... 

Interest in precipitation chemistry dates back to the 18th century, but only since 1977 has the U.S. established a national network for monitoring at a level sufficient to describe the chemical climate. The siting criteria, quality assurance, and standardized equipment and analytical methodology are addressed to insure the highest quality data for interpretative research. The national distribution of concentration and deposition for calcium, ammonium, chloride, nitrate, sulfate, and pH are shown in a series of maps. 

A discussion of the quality of precipitation chemistry must include the analytical methods used as well as a description of the device used to collect samples. Most importantly, the quality of the data must be assured when assessing the impacts on the precipitationreceiving environmental system. Students of precipitation chemistry have used everything from glass bottles to baby bottle plastic liners to collect samples for analysis. Laundry baskets, staked to the ground, as well as fence-post mounted plastic bottles have also been... 

The author has briefly recounted the history of scientific interest in precipitation chemistry and focused attention on some of the important problems dealing with the quality assurance of analyzed samples. These considerations lead the author to conclude that comparisons between data collected prior to the late 1970 s and those... 

---