LB复合膜选择性检测水中痕量镉离子的方法研究

Development of the Simple Method with Combined LB Film for Selective Detection of Trace Cadmium in Water

开发了一种利用LB复合膜选择性地检测水中痕量镉离子的技术方法,研究了最佳LB复合膜检测器的制作条件.用表面活性剂十二烷基-(2-噻唑偶氮)间苯二酚(DTAR)作显色剂,对乙烯基硬脂酸盐(PVS)、十八烷基异丁烯酸盐(PMOA)、乙烯基-N-氨基甲酸十八烷基酯(PVOC)和顺丁烯二酸酐-1-十八烯(PMO)4种聚合物进行了强度实验,得出稳定的检测器结构,即偶数层DTAR上附着单层PVOC的LB复合膜.经过灵敏度实验,制作出最佳LB复合膜检测器DTAR6-PVOC1,在pH为7.5,温度40℃且搅拌的反应条件下,该检测器可以在10 min之内检出10-7mol/L镉,并可目视定性及半定量检测出水中痕量镉离子.水中可能共存的离子中只有Cu2+和Zn2+会干扰镉离子的检测,需要抑制.

The method using combined LB film for selective detection of trace cadmium in water was developed. Based on the principle of LB film theory, the authors investigated the best fabricating conditions to get stable combined LB film. In the research, dodecyl-（2-thiazolylazo） resorcinol was chosen as chelating chromophore and four polymers such as vinyl stearate, oetadecyl methacrylate, vinyl N-octadecylcarbamate, and maleic anhydride-ah-l-octadecene were tested to select the best protector for LB optical sensor, and the stable frame of LB film that is even number of DTAR plus odd number of PVOC was obtained. After sensitivity experiment, the best LB sensor DTAR6-PVOC1 for cadmium was produced. At pH 7.5, temperature 40 ℃ and mixing conditions, the sensor can detect 10^-7 mol/L of Cd within 10 minutes, and visual qualitative and half-quantitative detection were reliable. Some co-existent element such as copper and zinc would disturb the detection, and such disturbance should be controlled.