Flame atomic absorption spectrophotometry has been used for testing the algorithm of a computer program used for interpreting photoabsorptiometric data. Four attributes namely:maximum permissible range of calibration; maximum permissible spacing between calibration points; accuracy of standard additions extrapolation; and speed of computation were tasted. The calibration range for copper, can extend to 500 times the characteristic concentration while keeping biases less than ± 1 S.D. unit. For nickel and lead, the limit is 100 units of characteristic concentration. This permits measurement within the range of minimum cv. An Intel 80486DX microprocessor calculates all coefficients on a 255-point data set within 0.12s. The algorithm gives an accurate regression fit and it is suggested that it might usefully be incorporated into modern AAS equipment. ã 1999 Elsevier Science B.V. All rights reserved.