SPR生物传感器检测牛奶中氨苄青霉素残留

Detection of ampicillin residues in milk using SPR biosensor

将表面等离子体共振(SPR)传感器的高灵敏性与抗原抗体的高亲和性相结合,通过自组装分子技术将抗生素的单克隆抗体固定到传感器金膜表面,用于特异性吸附牛奶中的抗生素,实现了抗生素残留的快速、痕量检测。由于牛奶的成分复杂,在测量过程中牛奶中的某些成分产生的非特异性固定引入了极大的测量误差。因此,对牛奶进行了脱脂和稀释预处理,通过实验比对发现,对牛奶进行脱脂并稀释4倍后,其产生的非特异性固定基本消除,接近了纯水的测量水平。最后,对预处理后的牛奶进行了多浓度测量,并建立了不同浓度的氨苄青霉素牛奶样品的工作曲线。所采用传感器的最低测量限(LOD)达到了1.56μg/L(变异系数为7.8%),低于欧盟规定的牛奶中氨苄青霉素的最低检出限。

A biosensor based on surface plasmon resonance（SPR） was used to detect antibiotic residue in milk quickly and specifically. The monoclonal antibody was immobilized on the gold surface of SPR sensor with the selfassembled-monolayer technique. The sensor possesses high sensitivity due to SPR technology and high specificity due to the affinity between antigen and antibody. In addition to be binded to antibiotic, antibody was also bounded to other components in milk, which is called non-specific binding （ NSB ） , and will introduce great measurement error. So, the milk was defatted and diluted firstly. The experiment shows that the NSB of milk can be avoided after defatted and diluted 4 times, closing to deionized water. Furthermore, the processed milk samples with different ampicillin concentrations were measured and the work curve was built up. The limit of detection （LOD） of used sensor is 1.56 ug/L with 7.8 % CV. The LOD is lower than the maximum residue limit （MRL） of ampieillin.