A personal computer, coupled via a commercial interface to the spectrometer, is used to integrate the transient absorbance signals in atomic absorption spectrometry with electrothermal atomisation. Integration over a time interval closely matching the peak improves the detection limit and precision for the determination of thallium in water, compared with integration over a wider interval. For the determination of lead in copper, systematic errors due to overcompensation by the deuterium background corrector are avoided.