Ag(Ⅰ)在一种新硫脲衍生物介质中的极谱行为研究

POLAROGRAPHIC BEHAVIOUR OF Ag(Ⅰ) IN A NEW THIOUREA DERIVATIVE MEDIUM

在含 N-烯丙基-N^-对苯磺酸钠硫脲(简写 NTu)的碱性介质中(pH8.0～10.5)银离子可以导致两个极谱还原波,其半波电位分别为-0.65V 和-0.95V(vs.SCE)。对此体系进行了详细研究,结果表明,Ag(Ⅰ)与 NTu 在溶液中不形成络合物,电活性物为 C,C^-二(N-烯丙基-N-对苯磺酸钠)二硫甲脒(简写 NDF);NDF 在汞电极上发生不可逆还原,前波(-0.65V)具有吸附件质,而后波(-0.95V)为扩散波;NDF 在滴汞电极上的吸附符合 Frumkin 吸附等温式,该吸附前波的单扫描极谱是测定银的一种灵敏方法。本工作首次报道了与微量银离子直接关联的完整极谱波。

In a basic medium(pH8.0～10.5)containing N-allyl-N′-(sodium p-pheny- lsulphoate)thiourea NTu),two cathodic waves on the mercury electrode rela- ted to silver(I)were found at half wave potentials -0.65v and -0.95V (vs. SCE)respectively.Electrochemical and non-electrochemical techniques have been used to study the mechanism in detail,Results show that the first wave(-0.65V)is a adsorptive prewave whereas the second one(-0.95V)is a irreversibly diffasional controlled wave of NDF(the oxidized product of NTu).The adsorption of NDF obeys Frumkin adsorptive isotherm.