The Fluorescence Enhancement of Mercury Detected in Food Based on Rhodamine Derivatives
FAN Cai-ling1,2, XIE Pu-hui1, CUI Shu-min1, YANG Li-na1, SUN Qing1, AI Zhi-lu2，3*
1. College of Science, Henan Agricultural University, Zhengzhou 450002, China 2. College of Food Science and Technology, Henan Agricultural University, Zhengzhou 450002, China 3. Collaborative Innovation Center of Henan Grain Crops, Zhengzhou 450002, China
Abstract：Recently, the problem of food security is more and more serious, and people pay attention to mercury because of the toxic of it. A new approach for the determination of mercury content in foodstuff is devised. In this paper，first, we design and synthesis a new kind of fluorescent probe whose matrix based on rhodamine B, hydrazine hydrate and hydroxy benzaldehyde. Through the analysis of H-NMR spectra of the synthesized product L1, we confirm that the synthetic substance is the adjacent carboxyl benzaldehyde hydrazone structure generation of rhodamine B. Then, we measure the fluorescence signal intensity of the probe with different concentrations of mercury ions fully upon complexation by fluorescence spectrometer and we can study the relationship between the mercury ion concentration and the fluorescence intensity and draw the standard working curve. Following, It’s time to discuss the microwave digestion processing of tea，after digestion we use the synthetic probe L1 for determination of mercury content in tea. The experimental results show that the maximum excitation wavelength of the probe and coordination compound are 568.05 and 560.00 nm, the maximum emission wavelength are 587.94 and 580.00 nm. Then we can find the best testing conditions to improve the degree of accuracy, that is: room temperature, 50% the methanol solution, 3.0 mL pH 4.0 buffer solution, in the extent of 30 min. The experimental results show that Na+, K+, Ca2+, Cu2+, Zn2+, Al3+ have little impact on the fluorescence intensity of the probe. Fe3+, Mg2+, Ba2+ has a weak enhancement to the fluorescence intensity of the probe. While a low concentrations of Hg2+ have an obviously enhanced effect on the fluorescence intensity of the probe. In contrast to other metal ions, the probe for Hg2+ has a good selectivity. Linear relationship between the magnitude of increase in fluorescence intensity and concentration of mercury ion was in the range of 5～20 ng·L-1 with detection limit (3S/N) of 1.9 ng·L-1. The proposed method was applied to determination of mercury ion in samples of tea and sausage and the obtained result and sample recovery were all satisfactory. The methods of analysis instrument has the advantages of simple structure, sensitivity, high accuracy, good selectivity and less volume of simple, without the need for enrichment, being very practical.
范彩玲1,2，谢普惠1，崔淑敏1，杨莉娜1，孙 青1，艾志录2,3* . 基于罗丹明类衍生物荧光增强的食品中汞检测 [J]. 光谱学与光谱分析, 2015, 35(05): 1300-1305.
FAN Cai-ling1,2, XIE Pu-hui1, CUI Shu-min1, YANG Li-na1, SUN Qing1, AI Zhi-lu2，3* . The Fluorescence Enhancement of Mercury Detected in Food Based on Rhodamine Derivatives . SPECTROSCOPY AND SPECTRAL ANALYSIS, 2015, 35(05): 1300-1305.
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