基于氧化石墨烯-纳米镍修饰电极的化学耗氧量即时检测系统

A Point of Care Testing System for Chemical Oxygen Demand Based on Graphene Oxide-Nickel Nanoparticles Modified Electrode

建立了一套流动态下即时测定化学耗氧量(COD)的电化学分析系统。以GO-NiNPs修饰的平面电极与3D打印薄层流通池构成检测模块,微型蠕动泵驱动试液流经电极表面,采用计时电流法进行测定。考察了修饰材料、介质和电化学操作条件对电极表面形态及分析性能的影响。此装置对COD的响应时间为1.5 min,样品用量约2 mL。在低浓度区间的线性响应范围为0.15~100 mg/L,线性方程i(μA)=3.974c(mg/L)+0.2295,相关系数R=0.9991,检出限0.04 mg/L;在高浓度区间的线性响应范围为100~450 mg/L,线性方程i(μA)=1.938c(mg/L)+230.9,相关系数R=0.9877。此系统对典型环境水样的测定结果与国标GB11914-89法测定结果间相关性良好,而耗时仅为其1/100,且无需使用任何贵重及毒害性试剂,避免了二次污染,具有良好的便携性。

An electrochemical analysis system for rapid determination of chemical oxygen demand （COD） inflow state was established. A planar electrode modified with GO-NiNPs was matched with a 3D printed thin-layer cell. The sample was driven smoothly through the electrode surface by a micro peristaltic pump and thenmeasured by chronoamperometry. The effect of modified materials, dielectric and electrochemical operatingconditions were investigated. The whole response time of COD was 1. 5 min and the demand for the samplewas about 2 mL. It turned out that the linear range of response in the low concentration region was 0. 15 -100 mg / L, the linear equation was i（μA）= 3. 974c （mg / L） ＋ 0. 2295 （r = 0. 9991） and the detection limitwas 0. 04 mg / L. The linear response range in the high concentration region was 100 -450 mg / L, and thelinear equation was i（μA）= 1. 938c （mg / L） ＋ 230. 9 （r = 0. 9877）. Compared with the national standardmethod （GB11914-89） for measuring the actual water samples （Qinhuai River, Xuanwu Lake and Nanjing tapwater）, the correlation between them was quite good and the analysis time was dropped to 1 / 100. This newsensing system provided an environmentally friendly and portable method for detection of COD without usingexpensive, highly corrosive and toxic reagents.