壳聚糖固定化脲酶生物传感器选择性测定铜离子

摘要

A biosensor was developed for determining copper ion based on the heavy metal inhibition on urease. This biosensor was fabricated by immobilizing urease into chitosan matrix at the surface of a pH electrode. Due to the accumulation of Cu2+in the chitosan matrix, the biosensor exhibited high sensitivity. NaI was proposed to add into the sample to suppress the interference of Hg2+and Ag+. Thus, the selective detection of Cu2+was achieved. It was shown that a good linear relationship between the inhibition rate and the logarithm of Cu 2+concentration was obtained in the range from 0.005 to 0.5μg/mL. The detection limit was found to be 0.002μg/mL. The total recovery of enzyme activity was possible by immersed the used biosensor in 0.5mmol/L EDTA solution after 5 min regeneration time.%基于重金属对脲酶的抑制作用，研制了用于测定铜离子的生物传感器。该生物传感器的制备以壳聚糖为载体，将脲酶固定于pH电极表面。由于壳聚糖对Cu2+的富集，该生物传感器展现出高灵敏度。在样品溶液中加入5 mmol/L NaI，可以消除Hg2+和Ag+的干扰，从而实现Cu2+的选择性检测。在0.005～0.5μg/mL的浓度范围内，脲酶活性的抑制率与Cu2+浓度的对数呈良好的线性响应关系，其检出限为0.002μg/mL。将使用后的生物传感器浸泡于0.5 mmol/L的EDTA溶液再生5 min，被Cu2+抑制的脲酶的活性可以得到恢复。