试验表明:在pH 4.35~4.45的缓冲介质中,由于核酸与表棓儿茶素棓酸酯-铜(Ⅱ)配合物之间的相互反应导致配合物所发射的荧光强度明显增加,且在激发波长330 nm和发射波长659 nm处测得的荧光增强程度与核酸浓度之间呈线性关系,据此提出了荧光光度法测定核酸的方法.在选定的最佳条件下,测得对小牛胸腺DNA(ctDNA)、鱼精DNA(fsDNA)及酵母RNA(yRNA)的线性范围依次为0.3~10.0 mg·L-1,0.4~4.8 mg·L-1及0.4~30.0 mg·L-1,其检出限(3S/K)依次为0.22,0.15,0.14 mg·L-1,加入3种不同浓度的ctDNA、fsDNA及yRNA标准溶液作回收试验,测得回收率在97.0%~104.4%之间,相对标准偏差(n=5)等于小于2.0%.

It was found that the fluorescence intensity of the coordination complex,epigallocatechin gallate with Cu(Ⅱ) ion [EGCG-Cu(Ⅱ)],was significantly enhanced through its interaction with nucleic acid in a buffer medium of pH 4.35-4.45,when measurements were made at wavelengths of 330 nm (λex) and 659 nm (λem).Linear relationship was obtained between the magnitude of enhanced fluorescence intensity and the concentration of nucleic acid.Based on these facts,a method for determination of nucleic acid was proposed.Linearity ranges for ctDNA,fsDNA and yRNA were found to be 0.3-10.0 mg·L-1,0.4-4.8 mg·L-1 and 0.4-30.0 mg·L-1,with detection limits (3S/K) of 0.22,0.15,0.14 mg·L-1 respectively under optimum condition.Tests for recovery were made by addition of standard solutions of ctDNA,fsDNA and yRNA at 3 different concentration levels,results of recovery obtained were in the range of 97.0%-104.4% with values of RSD′s (n=5)≤2.0%.