SERS技术应用于食品中罗丹明B的快速检测
Rapid detection of Rhodamine B in raw paprika and other food based on SERS technique
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摘要: 目的:罗丹明B(Rhodamine B,RB)是一种人工合成的三苯甲烷类碱性染料,因其具有潜在的毒性、致癌性被禁止在食品中添加。目前,在中国还没有关于罗丹明B检测的国家标准,也没有快速检测标准,建立合适的现场快速检测方法迫在眉睫。方法:借助表面增强拉曼光谱(SERS)技术,以金纳米溶胶为拉曼信号增强模块,利用自制样品前处理仪与便携式拉曼光谱检测仪,实现对辣椒制品、腊肉、果汁、葡萄酒等食品中RB的快速检测。结果:快速前处理技术与常规方法相比,SERS谱图结果差异不明显,且不受样品其他成分干扰,但分析时间由常规的4050 min缩短到约10 min,大大提高了检测效率;同时,以样品提取液为基质的RB溶液最低检测浓度可以达到0.5 mg/kg;以RB在1355 cm-1处的特征峰为内标信号进行归一化计算,在100、200、300μg/L三个添加水平下,得到其平均回收率在81.1%87.0%之间,相对标准偏差RSD在2.1%3.0%内。结论:通过对多种实际样品检测并将结果与成熟的实验室液相色谱法相比较,发现本检测方法样品前处理简单,耗时少,检测结果准确可靠,且仪器设备便携、易操作,可用于食品中RB的现场快速筛查或实验室预检。Abstract: Objective: Rhodamine B is one kind of synthetic alkaline triphenylmethane dye, which have been used as a food additive.But now it is proved to be a toxic and cancer-causing substance, and is forbidden to artificially add into food in China and EU. At present, the government has not enacted relevant testing standards, and no on-site test methods was put forward.Therefore it is imminent to establish an on-site rapid detection method.Method: Based on surface enhanced Raman spectroscopy ( SERS) technique, this experiment achieved the rapid detection of rhodamine B in chilli products, such as bacon, fruit juice, wine and other foods, used gold nanoparticle sol as Raman signal enhancement module, a home-made laser Raman spectra pretreatment apparatus and a portable Raman spectrum detector.Result: Compared with the conventional methods, the difference of SERS spectra was not obvious, and the results also were not affected by the sample composition, though the experimental time was shorten from 4050 min to about 10 min, and the minimum detection concentration for RB was 0.5 mg/kg. By using the intensity of 1355 cm-1 peak as a normalization standard, the recoveries for chili spikes ( 100, 200, 300 μg/L) in chilli powder ranged from 81.1% ~ 87.0% and the relative standard deviations ( RSD) from 2.1% to 3.0%. Conclusion: The actual samples purchased from the supermarket were tested by the quick method mentioned in this study. The results told us that this method was reliable compared with proven technique of LC, and the device used in this experiment is portable and easy to be operated, and the results also showed us that this method can be applied for site inspection and preliminary inspection in laboratory.