( 3 ) the piezoelectric quartz crystal impedance ( qci ) technique was employed to monitor in situ the pb2 + - induced precipitation of bsa onto a gold electrode and the precipitate dissolution via edta in an aqueous solution ( 3 )用壓電石英晶體阻抗法( pqci )現場監測了水溶液中鉛離子誘導牛血清白蛋白( bsa )沉淀及沉淀由na _ 2edta溶解的過程。