We studied the electrochemical behavior of 2-mercaptothiazoline (1,3-thiazolidine-2-thione) on silver (Ag)/quartz and gold (Au)/quartz electrodes electrochemically deposited it on silver metal film on Ag/quartz substrates, and investigated it using electrochemical quartz crystal microbalance (EQCM) analysis with AT-cut quartz crystals (9 MHz). We found that the electrocatalytic property of Ag/quartz was better than that of gold/quartz. In addition, 2-mercaptothiazoline was detected using high-performance liquid chromatography with an electrochemical (Ag) detector (HPLC-ECD). For direct current mode, with the current at a constant potential, and measurements with suitable experimental parameters, we found a linear concentration range from 0.01 to 0.80 μg mL⁻¹. The lower limit of detection using our method was approximately 0.1 ng. Findings using HPLC-ECD and HPLC with an ultraviolet detector were comparable.