Citation: FENG Yan, WANG Ji-Kui, ZHANG Bao-Jian, SUN Qian-Wen, LI Xiao-Lu, ZHANG Zhi-Yi, TANG Mei-Hua, CHEN Guo-Song. A Point of Care Testing System for Chemical Oxygen Demand Based on Graphene Oxide-Nickel Nanoparticles Modified Electrode. Chinese Journal of Analytical Chemistry, 2018, 46(7): 1055-1061. doi: 10.11895/j.issn.0253-3820.181031 [复制]
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) in flow 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 then measured by chronoamperometry. The effect of modified materials, dielectric and electrochemical operating conditions were investigated. The whole response time of COD was 1.5 min and the demand for the sample was 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 limit was 0.04 mg/L. The linear response range in the high concentration region was 100-450 mg/L, and the linear equation was i(μA)=1.938c (mg/L) + 230.9 (r=0.9877). Compared with the national standard method (GB11914-89) for measuring the actual water samples (Qinhuai River, Xuanwu Lake and Nanjing tap water), the correlation between them was quite good and the analysis time was dropped to 1/100. This new sensing system provided an environmentally friendly and portable method for detection of COD without using expensive, highly corrosive and toxic reagents.
GB11914-89, Water Quality-Determination of Chemical Oxygen Demand-Dichromate Method. National Standard of the People's Republic of China
水质化学需氧量的测定重铬酸盐法. 中华人民共和国国家标准. GB11914-89
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