Metal Detecting Sensors: A Review on the Transition from Traditional Sensors to Field-Portable Sensors

Recently, in-situ analyses have been required in a variety of situations for clinical, food, environmental, and industrial samples. Therefore, not only do devices have to be miniaturized, lightweight, affordable, portable, autonomous, reusable, or disposable, but the approaches used must also be straightforward to understand, friendly, and sensitive enough to yield exact and accurate findings. Electroanalytical chemistry concepts have an advantage over other approaches in that they provide inexpensive and efficient ways to handle them. Thus, it is essential for satisfying the continually changing needs of scientific and industrial research. In this review, the use of these electrochemical methods in metal analysis, particularly for toxic metals, and numerous examples that have been described in the literature over the past ten years are discussed. The detail starts with a description of the traditional sensors and is followed by descriptions and explanations of various cutting-edge devices that will become well-known field-portable sensors during this time

A simple and fast flow injection amperometry for the determination of methimazole in pharmaceutical preparations using an unmodified boron-doped diamond electrode

In this work, an automated flow injection analysis (FIA) connected to a boron-doped diamond electrode (BDDE) was originally developed for the analysis of methimazole in pharmaceutical preparations. At a modification-free BDDE, methimazole was easilly oxidized. For the analysis of the mechanisms occurring at the electrode surface, cyclic voltammetry was employed to evaluate the impact of fundamental experimental parameters, such as pH and scan rate, on the BDDE response. For the quantitative detection, the FIA amperometric approach was constructed and used as a fast and sensitive method. The suggested approach provided a broad linear range of 0.5–50 µmol/L and a low detection limit of 10 nmol/L (signal-to-noise ratio = 3). Furthermore, the BDDE was successfully utilized to quantify methimazole in genuine samples from a variety of medicines, and its performance remained steady after more than 50 tests. The findings of amperometric measurements exhibit excellent repeatability, with relative standard deviations of less than 3.9 and 4.7 % for intra-day and inter-day, respectively. The findings indicated that, compared with traditional approaches, the suggested method has the following advantages: quick analysis time, simplicity, highly sensitive output, and no need for complicated operational processes

Screen-printed electrodes modified with green-synthesized gold nanoparticles for the electrochemical determination of aminothiols

Commercially available gold screen-printed electrodes cured at high temperature were modified or functionalized at the surface with gold nanoparticles, mainly produced by a green synthesis method, and other carbon-based nanomaterials in order to enhance the electron transfer between the sulfhydryl groups of the aminothiols cysteine (Cys), methionine (Met), glutathione (GSH) and homocysteine (hCys) and the electrode. The electrochemical characterization by cyclic and differential pulse voltammetry of some of the modified electrodes showed an improved performance in terms of sensitivity, reproducibility, repeatability, linearity range and limits of detection (12, 1, 0.2 and 1 μmol L−1 for Cys, Met, GSH, hCys, respectively) and quantification (40, 2, 0.5 and 2 μmol L−1 for Cys, Met, GSH, hCys, respectively) as compared to unmodified units. Then, some of these modified devices were successfully applied to the determination of cysteine and methionine in dietary supplements by means of liquid chromatography with amperometric detection

Biomedical Probes Based on Inorganic Nanoparticles for Electrochemical and Optical Spectroscopy Applications

Inorganic nanoparticles usually provide novel and unique physical properties as their size approaches nanometer scale dimensions. The unique physical and optical properties of nanoparticles may lead to applications in a variety of areas, including biomedical detection. Therefore, current research is now increasingly focused on the use of the high surface-to-volume ratios of nanoparticles to fabricate superb chemical- or biosensors for various detection applications. This article highlights various kinds of inorganic nanoparticles, including metal nanoparticles, magnetic nanoparticles, nanocomposites, and semiconductor nanoparticles that can be perceived as useful materials for biomedical probes and points to the outstanding results arising from their use in such probes. The progress in the use of inorganic nanoparticle-based electrochemical, colorimetric and spectrophotometric detection in recent applications, especially bioanalysis, and the main functions of inorganic nanoparticles in detection are reviewed. The article begins with a conceptual discussion of nanoparticles according to types, followed by numerous applications to analytes including biomolecules, disease markers, and pharmaceutical substances. Most of the references cited herein, dating from 2010 to 2015, generally mention one or more of the following characteristics: a low detection limit, good signal amplification and simultaneous detection capabilities

Automated Online Solid-Phase Extraction Coupled with Sequential Injection-HPLC-EC System for the Determination of Sulfonamides in Shrimp

The use of fully automated online solid-phase extraction (SPE) coupled with sequential injection analysis, high-performance liquid chromatography (HPLC), and electrochemical detection (EC) for the separation and determination of sulfonamides has been developed. A homemade microcolumn SPE system coupled with sequential injection analysis (SIA) was used to automate the sample cleanup and extraction of sulfonamides. The optimal flow rate of sample loading and elution was found to be 10 μL/s, and optimal elution time of zone was 20–24 s. Under the optimal conditions, a linear relationship between peak area and sulfonamide concentrations was obtained in the range of 0.01–8.0 μg mL−1. Detection limits for seven sulfonamides were between 1.2 ng mL−1 and 11.2 ng mL−1. The proposed method has been applied for the determination of sulfonamides in shrimp. Recoveries in the range of 84–107% and relative standard deviations (RSDs) below 6.5% for intraday and 13% for inter-day were received for three concentration levels of spiking. The results showed that the present method was simple, rapid, accurate and highly sensitive for the determination of sulfonamides

Recent Electrochemical and Optical Sensors in Flow-Based Analysis

Some recent analytical sensors based on electrochemical and optical detectioncoupled with different flow techniques have been chosen in this overview. A briefdescription of fundamental concepts and applications of each flow technique, such as flowinjection analysis (FIA), sequential injection analysis (SIA), all injection analysis (AIA),batch injection analysis (BIA), multicommutated FIA (MCFIA), multisyringe FIA(MSFIA), and multipumped FIA (MPFIA) were reviewed

Flow Injection Determination of Urinary Protein Using Fluorescence Quenching of Tetraiodofluorescein

Abstract A flow injection analysis system with spectrofluorimetric detection has been developed for trace protein in urine. The protein assay is based on the ion-association of protein and tetraiodofluorescein (TIF) in the presence of Triton X-100 at pH 3.2. Although the TIF-protein ion associate produces red color compounds, fluorescence quenching caused by bonding with protein was measured at 560 nm (excitation: 313 nm). The quenching is applied to the protein determination. Linearity range was up to 10 mg/L bovine serum albumin and the correlation coefficient was 0.999. The detection limit (S/N = 3) was 0.6 mg/L with RSD 0.134% (n = 4). The FI system is available for rapid screening in diabetic diagnosis

Simple and Rapid Determination of Ferulic Acid Levels in Food and Cosmetic Samples Using Paper-Based Platforms

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Automated Online Solid-Phase Extraction Coupled with Sequential Injection-HPLC-EC System for the Determination of Sulfonamides in Shrimp

The use of fully automated online solid-phase extraction (SPE) coupled with sequential injection analysis, high-performance liquid chromatography (HPLC), and electrochemical detection (EC) for the separation and determination of sulfonamides has been developed. A homemade microcolumn SPE system coupled with sequential injection analysis (SIA) was used to automate the sample cleanup and extraction of sulfonamides. The optimal flow rate of sample loading and elution was found to be 10 µL/s, and optimal elution time of zone was 20-24 s. Under the optimal conditions, a linear relationship between peak area and sulfonamide concentrations was obtained in the range of 0.01-8.0 µg mL −1 . Detection limits for seven sulfonamides were between 1.2 ng mL −1 and 11.2 ng mL −1 . The proposed method has been applied for the determination of sulfonamides in shrimp. Recoveries in the range of 84-107% and relative standard deviations (RSDs) below 6.5% for intraday and 13% for inter-day were received for three concentration levels of spiking. The results showed that the present method was simple, rapid, accurate and highly sensitive for the determination of sulfonamides