基于二维相关技术的氯吡脲拉曼光谱分析

氯吡脲作为一种苯脲类生长调节剂，被广泛应用于果蔬中，但是氯吡脲若过量使用，会严重影响果蔬的内在质量，且摄入过多会影响人的身体健康。现有的检测方法，虽然技术上成熟、精度高，但技术条件要求高、样品预处理过程复杂、耗时、检测费用高。利用二维相关拉曼光谱技术对乙酸乙酯中氯吡脲的浓度变化进行检测研究，建立一种灵敏、快速、高效的检测果蔬中氯吡脲的技术提供理论基础，对食品安全具有重大意义。采集氯吡脲粉末的拉曼光谱图，结合氯吡脲分子的结构图可对拉曼光谱谱图中的峰进行归属。配置浓度分别为2.5，5.0，7.5，10.0，12.5，15.0，17.5和20.0 g·L-1的氯吡脲乙酸乙酯溶液并采集拉曼光谱，对不同浓度的氯吡脲乙酸乙酯溶液的光谱数据进行二维相关分析，得到氯吡脲的拉曼二维相关同步谱图和异步谱图，分析同步谱图得出842, 992, 1 044, 1 442和1 604 cm-1的几处交叉峰具有协同作用，随着氯吡脲浓度的升高而升高；分析异步谱图得出交叉峰敏感性为1 044 cm-1>992 cm-1>842 cm-1，1 735 cm-1>1 604 cm-1>1 442 cm-1，842 cm-1>1 735 cm-1。结果表明，乙酸乙酯中氯吡脲的拉曼特征吸收峰分别为842，992，1 044，1 442，1 604和1 735 cm-1，其中1 044 cm-1（苯环的环伸缩振动）、992 cm-1（吡啶环的环呼吸振动）、842 cm-1（C-O-N假对称的伸缩振动）、1 735 cm-1（C=O伸缩振动）对氯吡脲浓度变化比较敏感，敏感度顺序为苯环的环伸缩振动>吡啶环的环呼吸振动>C-O-N假对称的伸缩振动>C=O伸缩振动>多个耦合峰的C=C伸缩振动>C-H的变形振动。拉曼光谱与二维相关技术相结合可以准确地反映出氯吡脲随浓度变化，为果蔬中氯吡脲含量的检测奠定了理论基础。

Raman Spectroscopy Analysis of Forchlorfenuron Based on Two-Dimensional Correlation Technique

As a kind of Benzourea, Forchlorfenuronis widely used to regulate the growth of fruits and vegetables. However, excessive use of Forchlorfenuron extremely hinders the growth of agricultural products. The residual Forchlorfenuron taken by humans also leads to damage of health. Various technologies were limited to fulfil both high accuracy and low cost in detecting Forchlorfenuron, so simple and time-saving technologies need to be developed. In this paper, highly sensitive and efficient Raman spectroscopy based on two-dimensional correlation technique were applied to detect the concentration change of Forchlorfenuron in ethyl acetate solution. The development of this technology provided theoretical basis of relevant analysis method for detecting Forchlorfenuron, which has a great influence on food safety. Raman spectrogram of Forchlorfenuron powders and its formula were used to analyze the Raman peaks. Different concentration of 2.5, 5.0, 7.5, 10.0, 12.5, 15.0, 17.5, 20.0 g·L-1 Forchlorfenuron in ethyl acetate solution were also tested to analyze the relationship of Raman peaks with the concentration change by using the synchronous and asynchronous spectroscopy of Forchlorfenuron. The result of synchronous showed that a synergetic effect of the peaks occurred at 842, 992, 1 044, 1 442, 1 604 cm-1 and the intensity of peaks increased with the rise of Forchlorfenuron concentration. Meanwhile, The results of asynchronous spectroscopy showed that the sensitivity of peaks had the following relationship: 1 044 cm-1>992 cm-1>842 cm-1, 1 735 cm-1>1 604 cm-1>1 442 cm-1, 842 cm-1>1 735 cm-1. Raman characteristic absorption peaks of Forchlorfenuron in ethyl acetatesolution were determined to be 842, 992, 1 044, 1 442, 1 604 and 1 735 cm-1, respectively, among which the peaks at 1 044 cm-1 (stretching vibration of benzene), 992 cm-1 (breathing vibration of pyridine), 842 (C-N-O asymmetrical stretching vibration) and 1 735 cm-1 (C=O stretching vibration)were more sensitive to the concentration of Forchlorfenuron and the sensitive order were stretching vibration of benzene, breathing vibration of pyridine, C-N-O asymmetrical stretching vibration, C=O stretching vibration, C=C stretching vibration of various coupling peaks and C-H deformation vibration. Such a combination of Raman spectroscopy based on two-dimensional correlation technique could exactly analyze the concentration change of Forchlorfenuron in ethyl acetatesolution, which will provide a new idea and method for the detection of Forchlorfenuroncontent in fruits and vegetables.