KI-罗丹明6G荧光猝灭法测定火腿中的亚硝酸盐

Determination of nitrite in ham sausage by KI-rhodamine 6G fluorescence quenching method

酸性条件下,NO_(2)^(-)与过量的KI反应生成I_(3)^(-)阴离子,I_(3)^(-)可与罗丹明6G形成离子缔合物,使得罗丹明6G发生荧光猝灭,且体系的荧光猝灭值ΔF与NO_(2)^(-)的质量浓度呈良好的线性关系,该文据此原理建立了一种测定NO_(2)^(-)的新方法。通过控制变量法确定了该方法的最佳测定条件为:0.1 mol/L H2 SO4溶液2.0 mL、0.1 mol/L KI溶液2.0 mL、1.0 g/L吐温-80溶液0.5 mL、5×10^(-5) mol/L罗丹明6G溶液2.0 mL,荧光激发波长477 nm、发射波长552 nm,在此条件下测定水溶液中NO_(2)^(-)的线性范围为30~240μg/L,回归方程为ΔF=1.9444ρ-25.178,相关系数r=0.9975,检出限为20.3μg/L,相对标准偏差为2.7%(ρ=160μg/L,n=11),回收率为95.5%~105.3%。将该方法用于火腿肠中亚硝酸盐含量的测定,效果良好。

Under acidic conditions,NO_(2)^(-) reacts with excess KI to form I_(3)^(-) anion.And I_(3)^(-) forms an ion association with rhodamine 6G which quenched the fluorescence quenching of the complex,and the fluorescence quenching values of the system were F and NO_(2)^(-).The mass concentration had a good linear relationship,and a new method for determining NO_(2)^(-) was established accordingly.The optimal measurement conditions of the method were determined by the controlled variable method.These conditions were 0.1 mol/L H2 SO4 solution 2.0 mL,0.1 mol/L KI solution 2.0 mL,1.0 g/L Tween-80 solution 0.5 mL,5.0×10^(-5) mol/L Rhodamine 6G solution 2.0 mL,fluorescence excitation wavelength 477 nm,emission wavelength 552 nm.Under these conditions,the linear range of NO_(2)^(-) in aqueous solution was 30-240μg/L and the regression equation wasΔF=1.9444ρ-25.178.In addition,the coefficient r=0.9975 and the detection limit was 20.3μg/L.Moreover,the precision relative standard deviation(RSD)was 2.7%(ρ=160μg/L,n=11)and the recovery was between 95.5%and 105.3%.This method can be used for the determination of nitrite content in ham sausage with satisfactory results.