Singh Ashok Kumar, Saxena Puja, Mehtab Sameena, Gupta Barkha
Department of Chemistry, Indian Institute of Technology-Roorkee, India.
Anal Sci. 2006 Oct;22(10):1339-44. doi: 10.2116/analsci.22.1339.
We have developed a highly La(III)-selective PVC membrane electrode based on a hexaaza macrocycle, 8,16-dimethyl-6,14-diphenyl-2,3,4:10,11,12-dipyridine-1,3,5,9,11,13-hexaazacyclohexadeca-3,5,8,11,13,16-hexaene [Bzo2Me2Pyo2(16)-hexaeneN6] (I) as membrane carrier, dibutylbutyl phosphonate (DBBP) as solvent mediator and sodium tetraphenylborate (NaTPB) as lipophilic additive. The best performance was given by the membrane of macrocycle I having a composition 10:260:5:120 (I:DBBP:NaTPB:PVC). The electrode exhibits a Nernstian response to La(III) ion in the concentration range 1.0x10(-1)-7.94x10(-7) M with a slope of 19.8+/-0.2 mV/decade of concentration and a detection limit of 5.62x10(-7) M. The response time of the sensor is 12 s and it can be used over a period of 4 months with good reproducibility. The electrode works well over a pH range of 2.5-10.0 and in partially non-aqueous medium with up to 30% organic content. The sensor was also used as an indicator electrode in potentiometric titration of La(III) ions with EDTA and for determining La(III) concentration in real samples.
我们基于六氮杂大环化合物8,16 - 二甲基 - 6,14 - 二苯基 - 2,3,4:10,11,12 - 二吡啶 - 1,3,5,9,11,13 - 六氮杂环十六碳 - 3,5,8,11,13,16 - 六烯[Bzo2Me2Pyo2(16)-六烯N6]（I）作为膜载体、二丁基丁基膦酸酯（DBBP）作为溶剂介质以及四苯硼酸钠（NaTPB）作为亲脂性添加剂，开发了一种对La(III)具有高选择性的PVC膜电极。大环化合物I组成比例为10:260:5:120（I:DBBP:NaTPB:PVC）的膜表现出最佳性能。该电极在1.0×10⁻¹ - 7.94×10⁻⁷ M的浓度范围内对La(III)离子呈现能斯特响应，斜率为19.8±0.2 mV/浓度 decade，检测限为5.62×10⁻⁷ M。传感器的响应时间为12 s，并且可以在4个月的时间内良好重现地使用。该电极在pH值2.5 - 10.0的范围内以及有机含量高达30%的部分非水介质中工作良好。该传感器还用作指示电极，用于La(III)离子与EDTA的电位滴定以及测定实际样品中的La(III)浓度。
