摘要
酸性介质中,NO_2与过量4-羟基香豆素迅速反应,其产物经Na_2S_2O_3还原后在碱性介质中能发较强的荧光,在适量β-CD存在下,由于β-CD的包络作用荧光大大增强.λ_(ex)/λ(em)=332/457nm,亚硝酸盐(NaNO_2计)在1～1200ng/25mL范围内与荧光强度呈良好线性关系,检出限40pg/mL.据此建立的亚硝酸盐荧光测定法灵敏度高,选择性好,数据稳定且操作简便.用于饮用水和肉制品中亚硝酸盐测定,结果满意.本文还对α-、β-、γ-CD和多种有机溶剂的影响进行了对比研究,测得了β-CD对反应产物的包络常数.
Nitrite ion reacts rapidly with 4-hydroxycoumarin in acidic solution to yield their nitroso-derivative, 3-nitroso-4-hydroxycoumarin which is nonfluorescent because of the electron-withdrawing effect of the nitroso group. After the nitroso derivative is reduced by Na2S2O3, the final product, 3-amino-4-hydroxycoumarin, is highly fluorescent in the alkaline medium and its fluorescence intensity is largely enhanced in the presence of β-cyclodex-trin(β-CD) because of inclusion complexation. The fluorescence maximum wavelengths are λex/λem = 332/457 nm, the fluorescence intensity is proportional to the nitrite concentration in the range of 1-1200 ng/25 mL, and the detection limit is 40 pg/mL. The method has been satisfactorily applied to the determination of nitrite in drinking water and meat products. In this paper, the effects of various cyclodextrins(α-CD,β-CD and γ-CD) and organic solvents are also studied.
出处
《分析化学》
SCIE
EI
CAS
CSCD
北大核心
1995年第5期512-516,共5页
Chinese Journal of Analytical Chemistry
基金
国家自然科学基金
北京市自然科学基金
关键词
羟基香豆素
亚硝酸盐
环糊精
荧光光度法
4-Hydroxycoumarin, nitrite, β-cyclodextrin, fluorescence analysis
