CAJ | 학술논문

该文利用烛灰,设计开发一种基于碳纳米颗粒修饰的丝网印刷电极,并对该电极的性能进行了评估.扫描电子显微镜显示修饰后的工作电极表面碳纳米颗粒分布均匀,直径约几十纳米.电极表征时,修饰电极氧化峰高13.76 mA,还原峰高11.85 mA,峰电位差为267 mV.在使用方波阳极溶出法检测含75μg/L Cd2+缓冲液时,修饰电极峰高为3.123μA.使用修饰电极检测不同Cd2+浓度缓冲液时,将峰高与Cd2+浓度进行数量关系拟合,获得拟合方程,R2=0.998.该修饰电极Cd2+浓度检测限可达到0.91μg/L.将其用于百合样本检测,加标回收率为99.2%~100.8%.该文修饰碳纳米颗粒丝网印刷电极可为其他检测对象或其他检测环境下的检测提供参考.
해문이용충회,설계개발일충기우탄납미과립수식적사망인쇄전겁,병대해전겁적성능진행료평고.소묘전자현미경현시수식후적공작전겁표면탄납미과립분포균균,직경약궤십납미.전겁표정시,수식전겁양화봉고13.76 mA,환원봉고11.85 mA,봉전위차위267 mV.재사용방파양겁용출법검측함75μg/L Cd2+완충액시,수식전겁봉고위3.123μA.사용수식전겁검측불동Cd2+농도완충액시,장봉고여Cd2+농도진행수량관계의합,획득의합방정,R2=0.998.해수식전겁Cd2+농도검측한가체도0.91μg/L.장기용우백합양본검측,가표회수솔위99.2%~100.8%.해문수식탄납미과립사망인쇄전겁가위기타검측대상혹기타검측배경하적검측제공삼고.
People are more and more interested in health foods with the improvement of living standard. Edible lily tastes sweet with a little bitter and can be used to treat cough, phthisis, beriberi, and so on. There are almost 10 species of edible lily in China. The production of lily is in rapid expansion. However, the sample of lily is usually found to have cadmium (Cd) above the national standard. Cd is one of the toxic heavy metals. It will cause damage of lung and kidney. There are a lot of methods to detect the cd in foods, such as graphite furnace atomic absorption spectrometry, atomic fluorescence spectrometry, and spectrophotometry. Although these methods have high precision, they need large-scale equipment, high cost, and professional staff, and even some use toxic reagents. Scientists developed several rapid determination methods, one of which was electrochemical detection. In this paper, we designed a novel electrode, which combined screen printing technique with carbon nanodots to detect cd in lily. Carbon nanodots were prepared with candle soot which was low-cost and easily obtained. The carbon nanodots of 1.5μL dissolving in dimethyl formamide were added twice onto the working electrode of screen-printed electrode which was fabricated in our laboratory. Using scanning electron microscope to compare the surface texture of modified screen-printed electrode with original one, we found that the former had more uniform particles. We also compared the electrochemical performance by cyclic voltammetry. The result showed that the modified screen-printed electrode had larger peak current and smaller peak separation which meant superior electrochemical performance. Furthermore, we tested an HAc-NaAc buffer solution with 75μg/L Cd2+ using 2 different electrodes noted above by square-wave anodic stripping voltammetry. The peak potential of original screen-printed electrode was?0.65 V, while modified one was?0.64 V. The anodic stripping voltammogarm showed that the carbon nanodots modified electrode had larger response current and peak height. So we used the screen-printed electrode modified with carbon nanodots to detect a series of HAc-NaAc buffer solutions with different Cd2+ concentrations (30, 45, 60, 75 and 90μg/L). The peak potential of very curve was -0.64 V. We found that peak height enlarged with the Cd2+ concentration increasing. A regression equation of peak height and Cd2+ concentration was obtained by calculating the data above. And the limit of detection was 0.91μg/L according to the triple standard error principle. Get 4-5 g fresh lily, and then pound it to paste. Transfer the lily paste into conical flask. And digest the lily sample with 15 mL HNO3 and 5 mL H2O2 on the heating plate till moisture went. Finally, add 20 mL HAc-NaAc buffer solution to dissolve the residue, and then filter to get the solution for detection. The peak height of lily sample was used to calculate the Cd2+ concentration by the regression equation. The Cd2+ content of lily sample was 0.130 mg/kg, while the relative standard deviation was 1.1%. The Cd2+ content of lily was smaller than the China national standardNY861-2004 andWM/T2-2004. We also measured the recovery of standard addition of lily sample, which was 99.2%, 99.8% and 100.8%, respectively. It demonstrates that the modified electrode can be used to detect the cd content of lily. Because the carbon nanodots modified screen-printed electrode is low-cost, disposable, and easy to be produced, it will have a great prospect of application.