National Institute of Research and Development for Biological Sciences, Bioanalysis Center, Bucharest 060031, Romania.
Sensors (Basel). 2013 Jan 25;13(2):1603-13. doi: 10.3390/s130201603.
Numerous amperometric biosensors have been developed for the fast analysis of neurotoxic insecticides based on inhibition of cholinesterase (AChE). The analytical signal is quantified by the oxidation of the thiocholine that is produced enzymatically by the hydrolysis of the acetylthiocholine pseudosubstrate. The pseudosubstrate is a cation and it is associated with chloride or iodide as corresponding anion to form a salt. The iodide salt is cheaper, but it is electrochemically active and consequently more difficult to use in electrochemical analytical devices. We investigate the possibility of using acetylthiocholine iodide as pseudosubstrate for amperometric detection. Our investigation demonstrates that operational conditions for any amperometric biosensor that use acetylthiocholine iodide must be thoroughly optimized to avoid false analytical signals or a reduced sensitivity. The working overpotential determined for different screen-printed electrodes was: carbon-nanotubes (360 mV), platinum (560 mV), gold (370 mV, based on a catalytic effect of iodide) or cobalt phthalocyanine (110 mV, but with a significant reduced sensitivity in the presence of iodide anions).
已经开发了许多安培生物传感器，用于快速分析神经毒杀虫剂，其原理是基于抑制乙酰胆碱酯酶（AChE）。分析信号通过硫代胆碱的氧化来定量，该硫代胆碱是由乙酰硫代胆碱伪底物的水解酶促产生的。伪底物是阳离子，它与氯离子或碘离子结合形成盐。碘盐更便宜，但它具有电化学活性，因此在电化学分析设备中更难使用。我们研究了使用碘化乙酰硫代胆碱作为安培检测的伪底物的可能性。我们的研究表明，使用碘化乙酰硫代胆碱的任何安培生物传感器的操作条件都必须进行彻底优化，以避免出现错误的分析信号或降低灵敏度。不同丝网印刷电极的工作过电势分别为：碳纳米管（360 mV）、铂（560 mV）、金（基于碘的催化作用，为 370 mV）或酞菁钴（110 mV，但在存在碘阴离子时灵敏度显著降低）。
