A Practical AAS Data Rule Today the importanee of Atomic Absorption Spectrophotometry is unquestioned, and in many analytical chemistry labs, routine determination of up to 20 ar 35 different elements is common. This involves a continual changing of instrumental parameters with each batch of samples to he read for a different element, which entails varying the setting for resonant lines, either uv or vis, slit, fuel and oxidant flow, midant type, sensitivity and linearity data, necessity for special media, releasing agents, ionization-avoiding agents, pos-:.ma sible interferences, etc. Of course the trained operator gets familiar with many of these 8 : WTERFSREW~S dataand knows them by heart, hutthesafest procedure is to consult the operating Manual each time a different element is to he read. In CIMM's Labs the Perkin Elmer 403 AAS Spectrophotameter is used daily for analyzing ahout 30 different elements in a great variety of products, so that routine use of the "Cookbook"' is made to ascertain the appropriate operating parameters. An idea was conceived of putting all the necessary fundamental Parameters for potassium determination in a p , ~ 403. , data appearing in the "Cookbookn plus numerical data concerning wavelength sening: 383 visible; $lit 4: tiaw: 32: fuel and oxidant flows found by experiment, in a more practical .ir flow: 57: linearup 2 pg/ml K, A standard 2 pg/ml form. should read 0.22 A.U.. 1000 ilglml Li must be added to Thus we have constructed a circular slide rule consisting of a sbndards and samples,and the red filtermust be used, "sandwich" of three coneentrical light cardboard discs, the sandwiched disc being larger than the others (inner disc: 7 cm in radius, outer disc: 5.5 cm) held together by a small plastic bolt and nut. The outer smaller discs have a radial "window" to view columns of data which are located radially on bath sides of the lareest inner disc (see figure) The follo%ng data are recorded in this way: Line nm, Slit, CzH2Flow, Oxidant Flow, Linear up to pglml, Sensitivity pglmI1A.U. This list includes all the necessary data for - - ~erformine ~ " an analvsis. A color code is used for wavelen&h: red numbers far uv, blue numbers for vis; also far the kind of oxidant: red for air, blue for N20. Twenty elements may be located on each side thus giving 300 to 400 practical pieces of information in a small flat portable form that can he owned by each operator of the P E 403 thus improving speed and efficiency of operation.
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'Analytical Methods for AAS, Perkin Elmer Carp., Norwalk Conn., Sept. 76. Leopoldo Bustos I. Centro de Investigation Minera y Metalfirgica (CIMM) P.O. Box 170 Las Condes 10, Santiago, Chile
124 1 Journal of ChemicalEducation
