Zamani Hassan Ali, Rajabzadeh Ghadir, Ganjali Mohammad Reza, Norouzi Parviz
Department of Chemistry, Quchan branch, Islamic Azad University, Quchan, Iran.
Anal Chim Acta. 2007 Aug 13;598(1):51-7. doi: 10.1016/j.aca.2007.07.028. Epub 2007 Jul 14.
Highly selective and sensitive poly(vinyl chloride) (PVC) membrane electrodes based on 6-methyl-4-{[1-(2-thienyl)methylidene]amino}3-thioxo-3,4-dihydro-1,2,4-triazin-5-(2H)-one (MATDTO) as new carriers for gadolinium ion-selective electrode was reported. The membrane solutions containing PVC, o-nitrophenyl octyl ether (NPOE) as plasticizer, sodium tetraphenyl borate (NaTPB) as lipophilic ionic additive, and MATDTO, displays a calibration response for Gd3+ ions over a wide concentration range of 1.0x10(-6)-1.0x10(-1) M with Nernstian slopes of 19.8+/-0.2 mV per decade and a detection limit as 5.8x10(-7) M. The sensor has a relatively fast response time of <10 s and can be used in the pH range 3.2-8.7 for at least 2 months without any significant divergence in potentials. The selectivity coefficients for mono-, di-, and trivalent cations indicate good selectivity for Gd(III) ions over a large number of interfering cations. The membrane sensor was used as an indicator electrode in the potentiometric titration of Gd(III) ions with EDTA. The proposed electrode was also applied to the determination of concentration of Gd(III) ions in soil and sediment samples and validation with CRMs.
报道了一种基于6-甲基-4-{[1-(2-噻吩基)亚甲基]氨基}-3-硫代-3,4-二氢-1,2,4-三嗪-5-(2H)-酮（MATDTO）作为钆离子选择性电极新载体的高选择性和灵敏的聚氯乙烯（PVC）膜电极。含有PVC、邻硝基苯基辛基醚（NPOE）作为增塑剂、四苯基硼酸钠（NaTPB）作为亲脂性离子添加剂以及MATDTO的膜溶液，在1.0×10⁻⁶ - 1.0×10⁻¹ M的宽浓度范围内对Gd³⁺离子呈现校准响应，能斯特斜率为每十年19.8±0.2 mV，检测限为5.8×10⁻⁷ M。该传感器响应时间相对较快，小于10秒，可在pH值3.2 - 8.7范围内使用至少2个月，电位无明显偏差。一价、二价和三价阳离子的选择性系数表明该传感器对Gd(III)离子相对于大量干扰阳离子具有良好的选择性。该膜传感器用作以EDTA电位滴定Gd(III)离子时的指示电极。所提出的电极还应用于测定土壤和沉积物样品中Gd(III)离子的浓度，并与有证标准物质进行了验证。
