REPORT Things as They Are," published two decades before Walsh s t a r t e d his work (15): "There is no dearth of methods that are entirely satisfac tory for the determination of ele ments when they occur alone. The rub comes in because elements never occur alone, for nature and man both frown on celibacy." These noncelibate elements could be measured more quickly, more reli ably, and less expensively by AAS than by methods commonly used in the late 1950s. AAS did a superior job of analyzing "things as they are." How were elemental analyses done before AAS? This question was asked by Zoe Gros ser at a preliminary presentation of this paper to people at P-E. Her ques tion is a good one because a genera tion of fortunate analysts has grown up without being forced to consider some of the old problems. The answer depends on many specifics, of course, and my perceptions come from experi ence in the analysis of agricultural and biological materials. First, many fewer analyses were done, especially at trace levels. Those that were done usually required con
siderably more chemical manipulation than is common today. Consider major constituents. Potassium in fertilizer was measured gravimetrically after separation from interferences and precipitation as K 2 PtCl 6 . It was a la borious procedure even if the need to recover and reuse the platinum was not considered. The flame photometer was used for potassium in most other sample types, and later flame meth ods were refined to yield acceptable results for fertilizers. Calcium and magnesium were normally measured by two EDTA titrations, the first to measure calcium and the second to de termine calcium plus magnesium. Magnesium was obtained by differ ence. Good results usually were ob tained for calcium, but those for mag nesium left much to be desired— especially for cases of large Ca/Mg ratios. If I were to pick a single ele ment for which AAS made the great est difference, it would be magnesium. For determination of trace ele m e n t s , the emission spectrograph was used extensively in large labora tories that could afford one. Polarographic methods were used for a few elements, notably Pb, Cu, Zn, and Cd. However, probably more trace
determinations were done spectrophotometrically or colorimetrically than by any other class of methods. Many books dealing exclusively with such methods were published; the classic work of Sandell (16) is one ex ample. The methods lacked the spec ificity inherent in the atomic spec trum, and extensive manipulations— including pH control, extraction, back extraction, distillation, and ad dition of masking agents—were the norm. In many cases, chemical sepa rations were required to enhance sensitivity and to control interfer ences. Keep in mind, too, that certi fied biological reference materials for quality assurance did not exist. A skilled and patient analyst who had the ability to devise and carry out a q u a l i t y - c o n t r o l scheme from the ground up was essential for reliable results. Contamination was an everpresent problem because of the num ber of reagents and the amount of manipulation required. Indeed, high blanks probably were responsible for more profanity per hour in labs of the day than any other single factor. To day, even though we typically work at concentration levels 1-2 orders of magnitude lower, the simplicity of
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