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食品安全问题越来越严重,汞作为有害离子之一受到人们的广泛关注,为了寻求茶叶和火腿肠中汞含量测定的新方法。首先以罗丹明B,肼水化合物,邻羧基苯甲醛为原料反应生成一种新型的Hg2+荧光增强型探针;接着,通过荧光光谱仪测量探针与不同浓度汞离子络合后的荧光强度,研究汞离子浓度与荧光强度的关系,绘制出标准工作曲线;然后,对茶叶进行微波消解,消解后用合成的探针测定茶叶中汞的含量。结果表明:探针和络合物的最大激发波长为568.05和560.00nm,最大发射波长为587.94和580.00nm;检测的适宜条件为:溶剂为50%甲醇水溶液,3.0mL pH 4.0的缓冲溶液,反应时间30min内。该探针对Hg2+有很好的选择性,Na+,K+,Ca2+,Cu2+,Zn2+,Al 3+对此探针的荧光强度几乎没有影响,Fe3+,Mg2+,Ba2+对此探针的荧光强度仅有微弱的增强,而很低浓度的Hg2+对此探针的荧光强度有显著的增强作用。Hg2+浓度在5~20ng·L-1范围内线性相关系数为0.951 2,检出限为1.9ng·L-1;对茶叶和火腿肠样品进行Hg2+加标回收实验,标准回收率分别为101.1%,92.6%。该方法仪器结构简单,灵敏度,准确度高,选择性好且用样量少,无需富集,有很强的实用性。
The problem of food safety is getting more and more serious. Mercury, as one of the harmful ions, has drawn people’s attention. In order to find a new method to determine the content of mercury in tea and sausage. First, rhodamine B, hydrazine hydrate and ortho-carboxybenzaldehyde were used as raw materials to produce a new type of Hg2 + fluorescence enhancement probe. Then fluorescence intensity of the probe was measured by fluorescence spectroscopy after complexing with different concentrations of mercury ions. Mercury ion concentration and fluorescence intensity relationship, draw the standard working curve; and then, microwave digestion of tea, after digestion with synthetic probe determination of mercury content in tea. The results showed that the maximum excitation wavelength of the probe and the complex were 568.05 and 560.00nm, the maximum emission wavelength was 587.94 and 580.00nm. The suitable conditions for the detection were as follows: the solvent was 50% aqueous methanol solution, 3.0mL pH 4.0 buffer solution, Within 30min. The probe has good selectivity for Hg2 +. The fluorescence intensity of this probe is almost not affected by Na +, K +, Ca2 +, Cu2 +, Zn2 + and Al3 +. The fluorescence intensity of Fe3 +, Mg2 + and Ba2 + Weakly enhanced, and very low concentration of Hg2 + on the fluorescence intensity of this probe significantly enhanced. The linear correlation coefficient of Hg2 + concentration in the range of 5 ~ 20ng · L-1 was 0.951 2, and the detection limit was 1.9ng · L-1. The Hg2 + spiked recoveries of tea and sausage samples were 101.1% , 92.6%. The method has the advantages of simple structure, high sensitivity, high accuracy, good selectivity, small sample size, no enrichment and strong practicability.