三元离子缔合物测定牛奶中的四环素残留

Determination of tetracycline residues in milk using ternary ion-association complexes

在醋酸溶液中,四环素(tetracycline,Tc)与Cu^(2+)形成螯合阳离子,然后进一步与带负电荷的铬天青S通过静电引力形成三元离子缔合物,导致反应体系的共振散射信号增强,据此建立了一种测定痕量Tc的共振散射光谱新方法。在最佳条件下,波长700 nm处,Tc浓度与体系共振散射强度的增加值(ΔI)在0.2~22μmol/L呈良好的线性关系,其线性回归方程为:ΔI=1.021×107c+1.437(c为Tc的浓度,mol/L),方法的检出限为8.81×10-9mol/L,相关系数r=0.999 0。将该方法应用于牛奶样品中Tc的测定,回收率为100.00%~101.20%。

In HAc solution, tetracycline（Tc） reacted with Cu2＋ to form cation chelates, which further reacted with chromeazurol S to form a ternary ion-association complexes. This enhanced resonance scattering signals. A new resonance light scattering method was established for the determination of trace Tc. Under the optimal conditions, the increase of the intensity（AI） at 700nm was linear to concentration of Tc in the range of 0.2 -22 μmol/L. Its regres- sion equation was AI = 1. 021 ×10^7c ＋ 1. 437, with a correlation coefficient of 0. 999 0 and a detection limit of 8.81 ×10^-9 mol/L. This method was applied in determination of Tc in milk samples with satisfactory results. The recovery was within the range of 100.00% - 101.20%.