| Because a lot of rotten food can produce large amounts of histamine and the allergic reaction of the body can also lead to a great deal of histamine release, these can do harm to our health. Frequent corruption food poisoning events caused by histamine, food contamination events caused by the poor storage technology, and trade barriers to our country all lead to serious economic losses. Therefore, it is particularly important to establish highly efficient, rapid, and sensitive methods for the detection of histamine.SPR sensing technology based on the theory of free electron resonance, which occurs on the surface of a thin gold film, has been used for detection of histamine in real-time, rapid, label free, no background interference, specific and simple operation.It can be developed into a high sensitive and rapid detection technology for the detection of histamine in food. In order to further reduce costs, save time and improve the detection sensitivity, our research group also developed electrochemical sensing technology to detect histamine in rotten food. Our research group completed the following research contents:1. Surface plasmon resonance sensing technology for the detection of histamine based on molecularly imprinted polymer film.In order to establish a MIP-SPR sensing technology, this work managed to combine the MIP material preparation technology with SPR sensing technology. The SPR sensing device is used as the transducer. The template molecule is histamine. On the sensor chip, MIP films were prepared by spin coating method. The MIP films are specific for the detection of histamine. This work successfully achieved the detection of histamine in food.In this work, the prepared MIP films contain imprinted nanocavities with the exact shape, size, and functional groups complementary to their target molecule. They can specifically identify histamine molecular. Our research group have also analysed the effect of p H conditions on the experiment. When the p H value at 7 ~ 9, histamine is mainly present in its single protonated state, the MIP film is almost fullydeprotonated, the binding capacity of the MIP film and histamine is strongest. The MIP synthesis has been optimised by varying the amount of MAA and EGDMA. In order to synthetize MIP films with the best recognition capability, the proportion of histamine, MAA and EGDMA in 1: 2: 4 had been selected for the biomimetic sensor experiments.Under optimal experimental conditions, our research group examined the performance of the MIP-SPR sensor for to detect different concentrations of histamine. The calibration curve formula is Y = 29.00 lg X- 31.90,The square of correlation coefficient is 0.9970. The sensing technique allows for the detection of histamine in the wide range from 25 ng/m L to 1000 ng/m L. This method enables the detection of histamine with a detection limit of 25 ng/m L. The sensing technique had good reproducibility, stability for the detection of histamine. Using structural analogs, it is demonstrated that the sensor platform is specific for the detection of histamine. The content of histamine in fish samples were detected using the spiked recoveries method. The determination results indicated good recoveries, ranging from 86.00 % to 109.00 %, with relative standard deviation(RSD) of 2.48 % to 4.66 %.2. Electrochemical sensor for the detection of histamine based on molecularly imprinted polymer film.In the purpose of providing fast detection technology and equipment, a detection method for histamine in water samples was established. MIP films were prepared on the gold electrode, and were characterized by electrochemical method.Electrochemical method for the detection of histamine was established.By the optimization of the experimental conditions, the results were similar to the MIP-SPR sensor. The electrochemical sensor had good reproducibility, stability, and selectivity for histamine detection. The calibration curve formula is Y = 3.440 lg X + 1.283(R2 = 0.9980). The detection limit of the established method was 0.5 ng/m L. The sensing technique allows for the detection of histamine in the wide range from 0.5 ng/m L to 50 ng/m L and detection time less than 30 min. The results show that the sensor has good stability, repeatability and reproducibility. The content of histamine in fermented bean curd samples were detected using the spiked recoveries8 method.The determination results indicated good recoveries, ranging from 92.36 % to 109.00 %, with relative standard deviation(RSD) of 0.47 % to 4.71 %.3. Molecularly imprinted electrochemical sensors based on Au NPs signal amplification for the detection of histamine.This work applied the MIP material preparation technology, nano material amplification technology and electrochemical sensing technology for the establishment of MIP-Au NPs-GCE electrochemical sensor. Au NPs were electrodeposited on the surface of GCE, which were used to amplify the sensor signal and to graft initiator AIBA. Then MIP film was prepared on the surface of GCE. This electrochemical sensor for the detection of histamine was established.The electrochemical behaviors of the electrode were studied and its change regulation was obtained. This work also verified the signal amplification effect of Au NPs. Optimization of the experimental conditions is the same as before.Electrochemical measurements were performed via electrochemical impedance spectroscopy(EIS)and the calibration curve obtained. The calibration curve formula is Y = 2.953 lg X + 1.968( R2 = 0.9988). The minimum detection limit of the established method was 0.22 ng/m L. The sensing technique allows for the detection of histamine in the wide range from 0.25 ng/m L to 100 ng/m L and detection time less than 30 min. The sensor had better reproducibility, stability, and selectivity for histamine detection. The content of histamine in fermented bean curd samples were also detected using the spiked recoveries method. The determination results indicated good recoveries, ranging from 93.57 % to 103.93 %, with relative standard deviation(RSD) of 0.93 % to 3.08 %.In this work, our research group constructed SPR sensing technology and electrochemical sensing technology to detect histamine in food. The two kinds of sensor technologies, each has its own merits. They can make up for each other’s technical deficiencies, for example, the preparation of MIP film on the SPR chip with simple operation, short time-consuming, no background interference, but it has long detection time. The electrochemical sensor is just the opposite. The three kinds of sensors were constructed to detect histamine all with specific recognition ability, goodreproducibility and stability, and all could be repeatedly to detect histamine. But the sensitivity of electrochemical sensors is more excellent, it show better detection effect after Au NPs amplification reaction signal. Development of a variety of methods to detect histamine, not only can reserve detection method, but also can satisfy the needs of different levels of detection. These simple and effective detection methods can be further developed to detect other chemical substance, it presents a very good prospects for development.
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