Ganjali Mohammad Reza, Norouzi Parviz, Gol-Mohammadi Mahmood, Mizani Farhang, Poursaberi Tahereh, Salavati-Niasari Masoud, Shamsipur Mojtaba, Hosseini Morteza, Javanbakht Mehran
Department of Chemistry, Tehran University, Tehran, Iran.
Ann Chim. 2003 Jul-Aug;93(7-8):679-90.
A strontium Schiff's base complex (SS) can be used as a suitable ionophore to prepare a sulfate-selective PVC-based membrane electrode. The use of oleic acid (OA) and hexadecyltrimethylammonium bromide (HTAB), as additives, and nitrobenzen (NB), dibutyl phthalate (DBP) and benzyl acetate (BA) as solvent mediators, were investigated. The best performance was observed with a membrane composition PVC: NB: SS: HTAB of 30%: 62%: 5%: 3% ratio. The resulting sensor works well over a wide concentration range (1.0 x 10(-2)-1.0 x 10(-6) M) with a Nernstian slope of -29.2 mV per decade of sulfate activity over a pH range 4.0-7.0. The limit of detection of the electrode is 5 x 10(-7) M. The proposed sensor shows excellent discriminating ability toward SO4(2-) ions with regard to many anions. It has a fast response time of about 15 s. The membrane electrode was used to the determination of zinc in zinc sulfate tablets. The sensor was also used as an indicator electrode in the potentiometric titration of SO4(2-) against barium ion.
锶席夫碱配合物（SS）可作为一种合适的离子载体，用于制备基于聚氯乙烯（PVC）的硫酸根选择性膜电极。研究了将油酸（OA）和十六烷基三甲基溴化铵（HTAB）作为添加剂，以及将硝基苯（NB）、邻苯二甲酸二丁酯（DBP）和乙酸苄酯（BA）作为溶剂介质的情况。当膜组成中PVC:NB:SS:HTAB的比例为30%:62%:5%:3%时，观察到最佳性能。所得传感器在较宽的浓度范围（1.0×10⁻² - 1.0×10⁻⁶ M）内表现良好，在pH值4.0 - 7.0范围内，硫酸根活度每变化一个数量级，能斯特斜率为-29.2 mV。电极的检测限为5×10⁻⁷ M。所提出的传感器对许多阴离子而言，对SO₄²⁻离子具有出色的区分能力。其响应时间约为15 s，速度很快。该膜电极用于测定硫酸锌片中的锌。该传感器还用作电位滴定法中以钡离子滴定SO₄²⁻时的指示电极。
