通过羧基化多壁碳纳米管(MWCNT′s-COOH)与巯基乙胺反应制得巯基化多壁碳纳米管(MWCNT′s-SH),将MWCNT′s-SH加入含有硼氢化钠的氯金酸溶液中,使生成的纳米金颗粒(AuNP′s)自组装到MWCNT′s-SH上,制得MWCNT′s-SH/AuNP′s粉末。将MWCNT′s-SH/AuNP′s粉末与微电极(ME)反复磨压使粉末进入ME顶端小孔内,烘干后即得MWCNT′s-SH/AuNP′s/ME。采用循环伏安法研究了多巴胺在修饰电极上的电化学行为。结果表明：多巴胺在该修饰电极上出现了一对氧化还原峰。多巴胺线性范围为5.0×10-6~6.4×10-4mol·L-1,检出限(3S/N)为5.1×10-9mol·L-1。修饰电极用于盐酸多巴胺注射液中多巴胺的测定,测定值与标示值相符,加标回收率在98.0%~103.0%之间。

Sulfhydryl multiwalled carbon nanotubes (MWCNT′s-SH) were prepared by the reaction of carboxy multiwalled carbon nanotubes (MWCNT′s-COOH) with sulfhydryl ethylamine. The MWCNT′s-SH was then added to a reaction mixture containing NaBH4 and HAuCl4, by which the gold nanoparticles (AuNP′s) produced were self-assembled onto MWCNT′s-SH and MWCNT′s-SH/AuNP′s powder was obtained. By pulverization and pressing of the MWCNT′s-SH/AuNP′s powder with the microelectrode (ME) to have the powder filled into the small hole at the top of ME, the modified MWCNT′s-SH/AuNP′s/ME was prepared. Electrochemical behavior of the modified electrode was studied by cyclic voltammetry. It was found that a pair of redox peaks given by dopamine was observed at the modified electrode. Linearity range for dopamine between 5.0×10-6 and 6.4×10-4mol·L-1 was obtained, with detection limit (3S/N) of 5.1×10-9mol·L-1. The proposed method was used in the determination of dopamine in injection samples, giving results in consistency with the labeled values. Recovery of the method was tested by standard addition method, giving recovery in the range of 98.0%-103.0%.