Over the past two decades, electrochemical biosensor devices have received great attention in the field of food analysis owing to their attractive performances. In the food industry the quality control during manufacturing process and final products requires quick and reliable analytical methods. A promising alternative to the traditional analytical techniques are the electrochemical enzymatic biosensors-devices that combine the robustness of electrochemical techniques with the specificity of biological recognition processes and offer great advantages due to size, cost, sensitivity, selectivity, and fast response. This brief review has attempted to summarise the literature on the recent progress in the development of enzyme biosensors with amperometric detection for quantitative analysis of glucose and lactate in various food samples. The review concludes with an outlook on the future challenges and perspectives in this area.

Recently, the development of eco-friendly, cost-effective and reliable methods for synthesis of metal nanoparticles has drawn a considerable attention. The so-called green synthesis, using mild reaction conditions and natural resources as plant extracts and microorganisms, has established as a convenient, sustainable, cheap and environmentally safe approach for synthesis of a wide range of nanomaterials. Over the past decade, biosynthesis is regarded as an important tool for reducing the harmful effects of traditional nanoparticle synthesis methods commonly used in laboratories and industry. This review emphasizes the significance of biosynthesized metal nanoparticles in the field of electrochemical sensing. There is increasing evidence that green synthesis of nanoparticles provides a new direction in designing of cost-effective, highly sensitive and selective electrode-catalysts applicable in food, clinical and environmental analysis. The article is based on 157 references and provided a detailed overview on the main approaches for green synthesis of metal nanoparticles and their applications in designing of electrochemical sensor devices. Important operational characteristics including sensitivity, dynamic range, limit of detection, as well as data on stability and reproducibility of sensors have also been covered. Keywords: biosynthesis; green synthesis; nanomaterials; nanotechnology; modified electrodes

Iridium oxide (IrO x) was electrodeposited onto glassy carbon electrode applying two-step potential cycling procedure. The electrocatalytic properties of the modified electrode IrO x /GC were evaluated with regards to electrochemical oxidation of nitrite and ascorbic acid (AA). The developed electrode-catalyst have been extensively studied by various electrochemical techniques. Differential pulse voltammetry (DPV) experiments indicated that the modified electrode possesses excellent electrocatalytic activity towards the oxidation of both nitrite and AA in neutral medium and offers simultaneous quantification of these substances. Constant potential amperometry studies also were performed-the IrO x / GC showed sensitive response to nitrite (159.7 μA mM-1 cm-2) with a wide linear range from 0.002 to 10 mM at 0.77 V (vs. Ag/AgCl, 3 M KCl), and to AA (96.2 µA mM-1 cm-2) with a linear range from 0.01 to 3 mM at 0.025 V. The detection limit was 0.63 μM nitrite and 4 μM AA, respectively, and both of them had fast response within 5 s. Considering the simple and rapid electrodeposition procedure for preparation, IrO x /GC is a new electrode-catalyst for sensitive and selective quantitative detection of nitrite and AA. The wide linear range, good selectivity, reproducibility of the amperometric response and long-time stability of the IrO x /GC make it a promising sensing material for practical nonenzymatic quantitative detection of nitrite and AA.

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Ruthenium oxide hexacyanoferrate (RuOHCF) film was electrochemically deposited onto a glassy carbon (GC) surface using consecutive cyclic voltammetry as a facile and green synthetic strategy. The electrochemical behaviour and electrocatalytic properties of the modified electrode RuОHCF/GC were evaluated with regards to electroreduction of hydrogen peroxide and iodate in a strong acidic medium (pHs 1.0–2.0) by using different electrochemical techniques, including cyclic voltammetry and amperometry at a constant potential. Electrochemical studies indicated that RuОHCF/GC possess a high catalytic activity in both studied reactions, fast response and good reproducibility of the current signal. The RuОHCF/GC exhibits enhanced electrocatalytic behaviour compared with other modified electrodes reported before. The simple and reproducible procedure for electrode fabrication, the wide linear range, anti-interference performance and long-time stability of the RuОHCF/GC make it a promising sensing material for practical quantitative determination of hydrogen peroxide and iodate. Remarkably, the reported modified electrode provided superior sensitive (1050 μA mM–1 cm–2) and highly selective amperometric detection of iodate.

Following our previous studies on the catalytic activity of electrochemically deposited on glassy carbon Rh electrocatalyst towards the reduction of hydrogen peroxide (H2O2), the electrochemical behaviour of the modified electrode was studied by means of cyclic voltammetry and chronoamperometry at pH-values from 5.0 to 9.0. The modified electrode exhibited a rapid, sensitive and reproducible response for the quantitative determination of H2O2 at low applied potential. Amperometry carried out at constant potential of 0 V (vs. Ag/AgCl, 3M KCl) at pH 6.0 (25 oC) gave the following operational parameters: detection limit of 4 μM, linear dynamic range  0.01 – 5.5 mM and electrode sensitivity of 377 μA mM−1 cm−2 .