Le Goff Thierry, Braven Jim, Ebdon Les, Scholefield David
Plymouth Environmental Research Centre, Department of Environmental Sciences, University of Plymouth, UK.
Anal Chem. 2002 Jun 1;74(11):2596-602. doi: 10.1021/ac010985i.
Ten nitrate-selective electrodes based upon rubbery membranes containing various betaine salts as sensors covalently bound to a cross-linked polystyrene-block-polybutadiene-block-polystyrene (SBS) polymer have been produced. The membranes were robust, highly selective, and effective over a pH range of 2-8. The best nitrate-selective electrode fabricated contained 10% m/m dicumyl peroxide, 40% 2-nitrophenyloctyl ether, 6.5% triallyl leucine betaine chloride and 43.5% SBS. The characteristics of this electrode were a linear Nernstian range of 1 x 10(-1) to 5 x 10(-6) mol dm(-3) NO3-, a limit of detection of 3.4 x 10(-7) mol dm(-3) NO3-, and a selectivity coefficient for nitrate against chloride, K(NO3-,Cl-)pot, of 3.4 x 10(-3). These figures represent a significant improvement on current commercial nitrate sensors. Response times were 1 min or less; stability of response and electrode lifetime in continuous use was also very satisfactory.
已制备出十种基于含各种甜菜碱盐的橡胶状膜的硝酸盐选择性电极，这些电极作为传感器与交联聚苯乙烯-嵌段-聚丁二烯-嵌段-聚苯乙烯（SBS）聚合物共价结合。这些膜坚固耐用、选择性高，在pH值2至8的范围内有效。所制备的最佳硝酸盐选择性电极含有10% m/m的过氧化二异丙苯、40%的2-硝基苯基辛基醚、6.5%的三烯丙基亮氨酸甜菜碱氯化物和43.5%的SBS。该电极的特性为：能斯特线性范围为1×10⁻¹至5×10⁻⁶ mol dm⁻³ NO₃⁻，检测限为3.4×10⁻⁷ mol dm⁻³ NO₃⁻，硝酸盐对氯离子的选择性系数K(NO₃⁻,Cl⁻)pot为3.4×10⁻³。这些数据表明相对于目前的商用硝酸盐传感器有显著改进。响应时间为1分钟或更短；连续使用时响应的稳定性和电极寿命也非常令人满意。
