2,4-二羟基苯甲醛缩甘氨酸的合成及荧光法测定粮食中痕量锌

SYNTHESIS OF 2,4-DIHYDROXYBENZALDEHYDE-GLYCINE AND FLUORIMETRIC DETERMINATION TRACE AMOUNTS OF ZINC IN CROPS

合成了新席夫碱试剂2,4 二羟基苯甲醛缩甘氨酸(DHBZGC),并测定了其结构,基于Zn(Ⅱ)与DHBZGC OP形成配合物,导致体系荧光增敏的特性,提出了一种测定痕量锌的荧光方法。在pH6.5～8.0,NaH2PO4 Na2HPO4缓冲溶液和OP存在时,Zn(Ⅱ)与DHBZGC形成1∶1的配合物。在λex为330nm,λem为445nm处产生的荧光增敏最大,Zn(Ⅱ)在0～100μg·L-1范围内符合线性关系,检出限为0.4μg·L-1。方法应用于粮食中痕量锌的测定,结果满意。

A new Schiff′s base reagent, 2,4-dihydroxybenzaldehydeglycine (abbreviated as DHBZGC) was synthesized by condensation of 2,4-dihydroxybenzaldehyde with glycine, and the product obtained was purified by recrystallization and its struture identified by IR-Spectrometry and elemeatary analysis. It was found that in a buffer medium of sodium dihydrogen phosphate-sodium hydrogen phosphate (pH6.5～8.0) and in the presence of OP, a complex, with a mole ratio of 1 to 1, is formed between DHBZGC and Zn(Ⅱ), leading to a remarkable enhamcement of fluorescence intensity of the reaction system. The fluorescence measurements were made at the wavelengths λ_(ex) 330nm and λ_(em) 445nm. Linear relationship between fluorescence intensity and concentration of zinc(Ⅱ) was obtained in the range of 0～100μg·L^(-1) and a detection limit of 0.4μg·L^(-1) was found. Based on the above mentioned findings, a new fluorescent method for the determination of trace amounts of zinc was established, and satisfactory analytical results were obtained when the proposed method was applied to the analysis of crops.