对二甲氨基苯甲醛缩氨基硫脲荧光猝灭法测定虾头中微量汞的研究

Determination of Trace Mercury in Shrimp Head Based on Fluorescene Quenching of p-Dimethylaminobenzaldehyde Thiosemicarbazone

采用对二甲氨基苯甲醛与氨基硫脲反应,合成对二甲氨基苯甲醛缩氨基硫脲(DMA),并用NMR对其结构进行表征,研究其荧光光谱。发现其水溶液在448 nm处发射强荧光。探讨DMA在水溶液中当有Hg^(2+)存在时,DMA的荧光可被完全猝灭,据此建立了荧光猝灭法测定微量Hg^(2+)的方法,其线性范围是0~1.5×10-5 mol/L,检出限为1.00×10-7 mol/L。该方法用于虾头中微量汞的测定,灵敏度较高,重现性好。

The compound, p-dimethylaminobenzaldehyde thiosemicarbazone（DMA） was synthesized; the fluorescence spectra were taken in aqueous solution. The structures of DMA were confirmed by NMR. The photophysical behavior was studied that compound recognition heavy metal ions in aqueous solution by steady-state fluorescence spectroscopy. It was observed that DMA emited fluorescence at 448 nm in aqueous solution and its fluorescence intensity was completely quenched upon interaction with Hg^2＋ ions. The method used for the determination of trace mercury in ShrimpHead based on fluorescene spectrophotometric was established. Linear relationship between the Fluorescene intensity and the concentration of mercury（Ⅱ） was obtained in the range of 0～1.5×10^-5 mol/L, with detection limit of 1.00×10^-7 mol/L. The method is simple, has a good selectivity and sensitivity.