PRECISION AND DETECTION LIMITS IN ZEEMAN GRAPHITE-FURNACE ATOMIC-ABSORPTION SPECTROMETRY

This is the first theoretical study of photometric errors in Zeeman gr aphite furnace atomic absorption spectrometry with evaluation of their effect on the precision in the traditional method of peak area determ ination and the pulse restoration method proposed earlier for lineariz ation and expansion of calibration curves. Besides the fraction of non -absorbed radiation, alpha, and Zeeman sensitivity ratio, R, the theor etical calculations make use of three more parameters, namely the ''en ergy'' value, E, the baseline offset compensation time, t(boc), and th e integration time, t(int). The theoretical calculations are supported by experimental data on detection limits for a number of elements and on the RSD obtained in Ag and Cd determinations. A comparison of the precision in the case of pulses with dips has shown the pulse restorat ion method to be superior over the traditional technique. The theoreti cal results can be used to improve the measurement precision and the d etection limits by proper modification of the spectrophotometer and op timization of experimental conditions.