胆碱测定电极的胆碱氧化酶固定化研究

为了得到快速、便捷、准确的食品中胆碱含量的检测方法,该文探究用于测定胆碱含量的光敏电极上胆碱氧化酶(choline oxidase, ChOx)固定化方法,采用壳聚糖包埋和戊二醛交联相结合固定化ChOx,通过单因素试验和响应面分析研究壳聚糖浓度、戊二醛浓度以及固定时间对ChOx活力的影响,优化出最佳的ChOx固定化条件,研究结果表明,在壳聚糖质量分数1%、戊二醛质量分数0.55%、固定时间1 h时,固定化ChOx的酶活力最高,可达17.2 U。扫描电镜表明光敏电极表面成功固定ChOx,此外固定于光敏电极的ChOx重复利用10次后酶活力保持在83%,贮存20 d后酶活力保持在86%,具有良好的重复利用性和贮存稳定性。该方法初步探究了测定食品中胆碱的光敏电极研制过程,为食品中胆碱的快速检测奠定一定的理论基础。

Immobilization of choline oxidase on electrode for choline determination

In order to get a rapid,convenient and accurate method for the determination of choline in food,this paper explored the immobilization method of enzyme on photosensitive electrode for the determination of choline content.Choline oxidase was immobilized by chitosan embedding and glutaraldehyde crosslinking.The effects of chitosan concentration,glutaraldehyde concentration and immobilization time on the activity of choline oxidase were studied by single factor experiment and response surface analysis.The immobilization conditions of choline oxidase were optimized.When mass fraction of chitosan was 1%,mass fraction of glutaraldehyde was 0.55%and immobilization time was 1 h,the activity of immobilized choline oxidase was the highest,reaching 17.2 U.Scanning electron microscopy showed that choline oxidase was successfully immobilized on the surface of the photosensitive electrode.In addition,the activity of choline oxidase immobilized on the photosensitive electrode remained at 83%after 10 times of reuse and 86%after 20 days of storage.The choline oxidase immobilized on the photosensitive electrode had good reusability and storage stability.The method preliminarily explored the development process of the photosensitive electrode for the determination of choline in food,which lays a theoretical foundation for the rapid determination of choline in food.