溴离子对银阳极溶出测定影响的研究

The Influence of Bromide Ion on the Determination of Silver by Anodic Stripping Voltammetry

本文研究了Ｂｒ￣－离子对银阳极溶出的影响，在０．５ｍｏｌ／ＬＨＮＯ＿３底液中测定银时加入５×１０￣（－４）ｍｏｌ／ＬＢ离子，可以提高灵敏度１０倍以上。其原因是银溶出时生成的Ａｇ￣＋离子与加入的Ｂｒ￣－离子结合生成ＡｇＢｒ沉淀，随后又与过量的Ｂｒ￣－离子生成［ＡｇＢｒ＿２］￣－络合物，加快了溶出反应的进行。富集１０ｍｉｎ，可以测定２．５×１０￣（－９）ｍｏｌ／ＬＡｇ￣＋离子。

The determination of Ag￣+ in 0.5mol/L HNO_3、-5×10￣(-4)mol/L Br￣-sing ASV isdeseribed. With the presence of Br￣-,the sensitivity increases for 10 times.The detection limit is 2.5×10￣(-9)mol/L with deposition period of 10 min. The mechanism is studied. In the stripping process,Agdeposiled on working etectrode surface is oxided to Ag￣+which reacts with Br￣-, gives rise to precipitateAgBr, and then complex [AgBr_2]￣-,the stripping process is therefore accelerated.Thus,the sensitivityis increased.