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Development of an ultra-sensitive electrochemical method for the determination of phosphate ion with molecular fractionation and adsorptive collection

开发一种通过分子分级和吸附收集测定磷酸根离子的超灵敏电化学方法

基本信息

批准号：
13640606
负责人：
YOKOI Kunihiko
金额：
$ 2.24万
依托单位：
Osaka Kyoiku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

To establish an ultra-sensitive method for the determination of phosphate ion, molecular fractionation followed by adsorptive voltammetry was investigated. The principle of the method is; (1)production of phosphomolybdenum blue via phosphomolybdic acid after the addition of molybdenum ion and ascorbic acid to phosphate ion solution, (2)separation of phosphomolybdenum blue from isopoly molybdenum blue by HPLC with molecular fractionation column, (3)decomposition of phosphomolybdenum blue to produce molybdenum ion, (4) indirect determination of phosphate ion by adsorptive stripping voltammetric determination of molybdenum ion. At pH 2, with using a column ofGS220HQ, molybdenum ion and ascorbic acid could be separated satisfactorily, however, phosphomolybdenum blue could not be detected. With a column of GL-W510, peak signal for phosphomolybdenum blue could be obtained. At the present stage, the response is not linear to the phosphate concentration because of tailing of the peak, however, this could be improved by further investigation for optimum condition. Adsorptive voltammetric determination of molybdenum ion with 3-C1-mandelic acid give a limit of detection of 5 pM. This method has a sensitivity of 1900 nA/nM/min which shows the potentiality of a limit of detection of 0.3 pM for molybdenum ion and 0.03 pM for phosphate ion. 4-C1- and 4-Br-mandelic acids were also shown to be good for the sensitive determination of molybdenum ion. Further, it was clarified that back donation from mercury electrode to a ligand is significant for the adsorption of the complex to the electrode. Eleetrophilic functional group bonded to aromatic ring in mandelic acid enlarged the rate of catalytic reaction in the presence of chlorate ion. Investigation for voltammetric speciation of trace metal ion and photolytic decomposition of organic compound was also carried out.

研究了分子分级吸附伏安法测定磷酸根离子的超灵敏方法。该方法的原理是：（1）在磷酸根离子溶液中加入钼离子和抗坏血酸后，通过磷钼酸制备磷钼蓝，（2）用分子分馏柱的HPLC分离磷钼蓝和同聚钼蓝，（3）磷钼蓝分解产生钼离子，（4）钼离子吸附溶出伏安法间接测定磷酸根离子。在pH = 2时，采用GS 220 HQ柱，钼离子与抗坏血酸能得到满意的分离，而磷钼蓝不能检出。采用GL-W510色谱柱，磷钼蓝有一个峰信号。在现阶段，由于峰拖尾，响应与磷酸盐浓度不是线性的，然而，这可以通过进一步研究最佳条件来改善。用3-C1-扁桃酸吸附伏安法测定钼离子，检出限为5 pM。该方法具有1900 nA/nM/min的灵敏度，这表明钼离子的检测限为0.3 pM，磷酸根离子的检测限为0.03 pM。4-C1-和4-Br-扁桃酸对钼离子的测定也有良好的灵敏度。此外，它被澄清，从汞电极的配体的反馈是显着的络合物的吸附到电极。扁桃酸中芳香环上的亲电官能团使氯离子存在下的催化反应速度加快。并对痕量金属离子的伏安形态和有机物的光解进行了研究。