A Disposable Sensor for Rapid Histamine Detection in Fish Using Molecularly Imprinted Carbon Paste Electrode

Abstract

Introduction: Histamine (HM), a toxic compound, is produced due to an enzymatic reaction when histidine (HS)-rich red fish such as tunas and other fish and their processed products are improperly stored, e.g., leaving them at room temperature. With the increasing popularity of raw fish consumption, HM analysis is mandatory for these fish in various countries. However, the conventional immunoassay method is time-consuming, costly, and technically demanding, burdening wholesalers heavily.Molecularly Imprinted Polymers-based materials are attractive materials for sensor fabrication due to their high selectivity, stability, and ease of production. In this study, we attempted to develop a Molecularly Imprinted Polymer grafted Carbon Paste (MIP-CP) for histamine sensing. Experimental Methods First, a radical polymerization initiator was fixed on the surface of graphite particles [1]. Next, histamine dihydrochloride, itaconic acid, and ethylene glycol dimethacrylate (EDMA) were dissolved in a mixture of distilled water and dimethylformamide to prepare a polymerization solution. The polymerization solution and initiator-fixed graphite were placed in a quartz tube and irradiated with a xenon lamp for 1 hr. HM was extracted and removed using acetic acid. MIP-CP was prepared by mixing MIP-grafted graphite and silicon oil containing ferrocene in a 7:3 weight ratio. Non-imprinted polymer (NIP)-CP was also prepared using the same procedure, except that HM was not added.Differential pulse voltammetry (DPV) was performed with electrodes packed with the obtained MIP-CPs on a disposable chip [2]. The performance of the HM sensor was evaluated based on the relationship between the oxidation current of ferrocene and HM concentration. (Measurement range 0 μg/mL~100 μg/mL) Experimental results The dependence of the oxidation current density on HM concentration at the NIP and MIP electrodes was confirmed (0.0085 μA-mL/μg, R²=0.9357). The increase in current density with increasing HM concentration at the MIP-CP electrode was more than three times greater than at the NIP-CP electrode. This confirmed that MIP-CP exhibited current changes corresponding to the interaction between HM and HM-imprinted sites. Furthermore, the current increased linearly with increasing HM concentration from 0-100 µg/mL. This dynamic range includes 50 µg/mL, which is considered the lower limit of acceptable Hm concentration in fish meat.However, the current value was constant for HS concentration at 0.75 µA over the range of 40-100 µg/mL and below. Therefore, the sensor is saturated with HS at concentrations above 40 µg/mL, and histidine interference can be excluded by subtracting 0.75 µA from the current value obtained when measuring the fish meat sample. Conclusion We successfully developed a reagentless, disposable histamine sensor using MIP-CP, which provides a rapid, reliable, and cost-effective method for histamine detection in fish.