镁敏化美他环素荧光显微成像技术应用于北京市密云县养殖场生鲜乳抗生素残留量的检测

Determination of Antibiotics Residues in the Raw Fresh Milk of Farms in the Miyun County of Beijing with Mg^(2+)-Sensitized Metacycline Fluorescence Microscopic Imaging Technique

采用抗生素治疗奶牛乳腺炎是目前普遍采用的一种方法,因此牛奶中抗生素残留问题倍受国际社会关注。寻求简便可行、灵敏度高的检测技术,以适用日趋严格的残留限量要求,保障人们安全、卫生地饮用牛奶至关重要、迫在眉睫。基于固载表面溶剂毛细流的自组装环效应,采用镁敏化美他环素荧光显微成像技术检测了北京市密云县4家养殖场生鲜乳中美他环素残留量,建立了一种检测新方法。实验表明,在pH9.99NH3-NH4Cl缓冲溶液及聚乙烯醇-124存在下,镁和美他环素能形成较强荧光的1∶1配合物,并在憎水性玻片表面形成自组装环,环直径0.93mm,环线宽26.2μm。当点样体积为0.50μL时,线性范围为2.2×10-13～3.6×10-12mol.ring-1(4.4×10-7～7.2×10-6mol.L-1),检测限(3σ)为8.8×10-14mol.ring-1(1.8×10-7mol.L-1)。应用于生鲜牛奶样品中抗生素的检测,得到了满意结果,回收率为93.8%～108%,RSD小于4.3%。

Mg2＋-sensitized metacycline fluorescence microscopic imaging technique was applied to detect the raw fresh milk of four cows breeding farms in the Miyun County of Beijing based on the capillary effect of solvent on solid supports. In the presence of NH3-NH4Cl buffer solution （pH 9.99） and PVA-124, Mg^2＋ and metacycline can form a strong fluorescence complex of 1∶1, and Mg^2＋-metacycline complex can form an SOR on the hydrophobic supports with the diameter of 0.93 mm and its ring belt width of 26.2 μm. By measuring the fluorescence intensity of the ring, the quantitative analysis of metacycline was achieved with the detection limit （3σ） of 8.8×10^-14 mol·ring^-1 （1.8×10^-7 mol·L^-1） and linear range of 2.2×10^-13-3.6×10^-12 mol·ring^-1 （4.4×10^-7-7.2×10^-6 mol·L^-1） when 0.50 μL droplet was spotted. This method has been satisfactorily applied to the determination of metacycline in the raw fresh milk samples with the recovery of 93.8%-108% and RSD less than 4.3%.