Abstract: Mini DPSA-1 device, coupled to screen-printed carbon electrodes (SPCE), was used for simultaneous rapid detection of lead, cadmium and copper in tea by differential potentiometric stripping analysis (DPSA). The optimized experimental parameters were as follows, Hg²⁺ concentration — 3×10^-4 mol/L, supporting electrolyte — 1.5 mol/L pH4.0 NH₄Cl, deposition potential — -1.1 V, final potential —-0.2 V, deposition time — 200 s. The potentiometric stripping response for lead, cadmium and copper following 200 s deposition was linear over the concentration range examined (20~840 μg/L) with r values of 0.99749, 0.99740 and 0.99612 and detection limit of 1.12 μg/L, 1.09 μg/L and 1.23 μg/L (S/N=3), respectively. The interferences of various metal ions were also examined in the determination of lead, cadmium and copper. No significant difference existed after the rapid detection results were compared with GB method using t test. In comparing with conventional detection technique, this detection method for lead, cadmium and copper in tea, using mini DPSA-1 instrument, coupled to SPCE by DPSA, was a cheaper rapid detection technique. It could achieve a high percentage of sample screening and be applied to the simultaneous rapid detection of lead, cadmium and copper in other food and environmental samples.

Key words: Mini DPSA-1, differential potentiometric stripping analysis, simultaneous rapid detection, tea, screen-printed electrode