Determination of Optimum Operating Conditions in Atomic Absorption Spectroscopy

Abstract

A statistical technique for the simultaneous study of response to several variables has been used in the estimation of “optimum„ operating conditions for the element Calcium in atomic absorption spectroscopy. The method is based on “response surface„ exploration, originally due to G.E.P. Box. This technique has several advantages over the traditional method of varying “one factor at a time.„ Direct estimates of the magnitude of the effects of changes in each instrumental variable are obtained, together with estimates of the interactions between two or more variables. The method leads to the efficient estimation of “optimum„ operating conditions, i.e., those levels of the instrumental variables at which percent transmission is a minimum and also the estimation of alternative levels of the several variables at which transmission can be maintained at a minimum. The results showed that, for the estimation of Ca, the four variables air pressure, air flow, gas flow, and “height above the blue cone„ are compensating in the sense that departure from minimum transmission due to change in one variable can be compensated by a suitable change in the other variables. In the absence of a theoretical solution to the problem of estimating “optimum„ operating conditions, it would seem that this method is the best available at the present time.