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- Amperometric enzyme sensor for the rapid determination of histaminePublication . Torre, Ricarda; Costa Rama, Estefanía; LOPES, Paula; Nouws, Henri; Delerue-Matos, CristinaThe concentration of histamine, a biogenic amine, in fish is considered a fish spoilage indicator. Therefore, the development of a rapid-response and portable tool that allows its on-site analysis is very interesting since the consumption of high amounts of histamine causes scombroid poisoning. Thus, in this work a simple enzymatic sensor for the determination of histamine, based on a screen-printed carbon electrode and the enzyme diamine oxidase, was developed. The enzyme was immobilized on the electrode surface through a simple cross-linking procedure employing glutaraldehyde and bovine serum albumin. Chronoamperometry was used as the detection technique; the sensor showed a short response time (60 s, -0.3 V) and the measurements were performed by only using 40 μL of sample solution. The sensor provides an useful linear range (between 1 and 75 mg L-1 in fish extract), excellent reproducibility (RSD = 2.6%) and is reusable for up to 7 measurements. The feasibility of the sensor was tested performing histamine analysis in fish extracts achieving recovery values of 103%.
- Diamine oxidase-modified screen-printed electrode for the redox-mediated determination of histaminePublication . Torre, Ricarda; Costa Rama, Estefanía; Nouws, Henri; Delerue-Matos, CristinaHistamine is an important biogenic amine because of its role in immune responses and the regulation of physiological functions. It is also used as a food freshness indicator, so its maximum concentration in fish is legally regulated. Although several robust and sensitive methods for histamine detection are already available, it continues to be a challenge to develop simple and portable devices that allow rapid histamine screening at any point of the fish production chain. Thus, in this work, a simple, miniaturized and low-cost sensor for histamine analysis was developed. The construction of the sensor only takes 30 min and consists of the immobilization of the enzyme diamine oxidase on the surface of a screen-printed carbon electrode by cross-linking. The quantification of histamine was achieved by chronoamperometry (+ 0.2V,120 s) using hexacyanoferrate (III) as a redox mediator. This selective sensor provided a low limit of detection (0.97 mg L−1) and accurate and precise results and was successfully applied to the analysis of spiked tuna and mackerel extracts,obtaining recovery values of 99–100%. Moreover, the sensor shows good stability, maintaining 87.7% of its initial signalafter 35 days.
- Food allergen control: Tropomyosin analysis through electrochemical immunosensingPublication . Torre, Ricarda; Freitas, Maria; Costa‐Rama, Estefanía; Nouws, Henri; Delerue-Matos, CristinaRegulations of the EU obliges the indication of the presence of allergens on food labels. This work reports the development of an electrochemical immunosensor to determine tropomyosin (TPM) – a major shellfish allergen – prevailing in the muscles of crustacean species. Two linear ranges between the signal and TPM concentration were obtained: between 2.5 and 20 ng mL−1 and between 30 and 200 ng mL−1, with a lowest limit of detection of 0.47 ng mL−1. The selectivity of the optimized immunoassay, tested with other food allergens (e.g., Cyp c 1, a fish allergen), assures the effective detection of TPM, enabling successful control of foodstuff labelling. Several (12) foods, containing high and low TPM concentrations and TPM-free samples, were analysed using the sensor. A conventional ELISA kit and recovery assays were used to evaluate the accuracy of the results.