分析化学中“检出限”的物理意义及测定方法探究

阐述了分析化学中各类分析方法的检出限的物理意义、测定方法及可能存在的问题,并论述了经典的检出限定义的局限性。在利用凝血酶适配体与凝血酶的特异性结合抑制Pt纳米颗粒对量子点荧光猝灭检测凝血酶和基于CuGeO_3纳米线和葡萄糖氧化酶(GOx)修饰的玻碳电极(GCE)生物传感器测定葡萄糖的分析方法中,由于测定信号与被检测物质浓度或浓度的对数成负相关关系,导致分析方法的检出限与经典的检出限测定产生一定的冲突,出现了测定精密度越高,检出限越差的异常情况。

Study on the Physical Meaning and Determination Method of "Detection Limit" in Analytical Chemistry

In this paper, we studied the physical meaning, measurement methods and potential problems of detection limit in analytical chemistry. The limitation of classical detection limit was also discussed. We studied the detection of thrombin by fluorescence quenching of Pt nanoparticles, based on the specific binding of thrombin aptamer to thrombin. We found a negative correlation between the measured signal and the logarithm of the concentration. In addition, the similar negative correlation was found in the determination of glucose by a glassy carbon electrode biosensor, based on CuGeO₃ nanowires and glucose oxidase. The detection limit of the above two method conflicted with the classical detection limits. It appeared abnormal that the better the determination precision, the worse the detection limit.