Automatic flow system for the sequential determination of copper in serum and urine by flame atomic absorption spectrometry

Once optimised and with a sample consumption of about 0.250 mL of serum and 7 mL of urine, the developed flow system allowed linear calibration plots up to 5 mg L−1 with a detection limit of 0.035 mg L−1 for SCu and linear calibration plots up to 300 μg L−1 with a detection limit of 0.67 μg L−1 for UCu. The sampling rate varied according to the module employed and was about 360 determinations h−1 (SCu module), 12 determinations h−1 (UCu module) or 24 determinations h−1 (12 urine and 12 serum samples; UCu and SCu modules simultaneously). Repeatability studies (R.S.D.%, n = 10) showed good precision for UCu at concentrations of 25 μg L−1 (2.54%), 50 μg L−1 (0.90%) and 100 μg L−1 (1.62%) as well as for SCu at concentrations of 0.25 mg L−1 (8.11%), 1 mg L−1 (3.11%) and 5 mg L−1 (0.90%). A comparative evaluation showed a good agreement between the results obtained in the analysis of UCu and SCu (n = 18) by both the developed methodology and the reference procedures. Accuracy was further evaluated by means of the analysis of reference samples (Seronorm™ Trace Elements Urine and Seronorm™ Trace Elements Serum) and the obtained results complied with the certified values.