Electrochemical determining device and method of pickling time lag of tin plate

Material is tested or analyzed by means of measuring its chemical variables. Hydrochloric acid in 6 equivalent is set in one 100-350 ml three necked bottle and heated on 90 deg.c water bath, and the parallel circuit of DC source and variable resistor, a function recorder, reference electrode, salt bridge and test sample are connected serially to form a closed loop. The change of the potential with time during the etching of sample in hydrochloric acid is measured and recorded with the function recorder, and the pickling time lag of tin plate can be determined based on the change of etched test sample in potential. The present invention is suitable for in-situ determination.