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Background: Electrochemical methods in drug analysis have a lot of advantages, including simplicity, speed, low-cost instrumentation, informing about the drug mechanism, and nonaffection by excipients in dosage forms. Electrochemical techniques utilize the advantages of nanomaterials to increase sensitivity and, in some cases, selectivity. Among these nanomaterials, metal oxide nanoparticles are also preferred by researchers because of their unique properties such as biocompatibility, stability, non-toxicity, and catalytic characteristic. Objective: This review provided brief information about metal oxide nanoparticles used in electrochemical sensors and summarized applications for drug analysis with these sensors in tables showing the studies in the literature during the last decade. Results: In the last decade, metal oxides are frequently used in electrochemical drug analysis as electrode modifier individually and with other nanomaterials especially carbon-based ones. All these studies showed that metal oxide nanoparticles increase the active surface area of the electrode and the catalytic activity. Conclusion: When metal oxide nanoparticles and carbon-based nanomaterials are used together, they create a synergistic effect that further increases catalytic activity and thus lowers detection limits to be obtained in nM even pM levels.

Cefpirome, which is a fourth-generation cephalosporin, was analyzed for the first time at a glassy carbon electrode using differential pulse voltammetry in this novel method. Different experimental conditions were optimized, such as pH and electrolyte type, to achieve a high peak current. Under the optimum conditions, the oxidation of cefpirome exhibited diffusion-controlled process depending on pH. Cefpirome was electrochemically determined at the linear range between 2-200 µM, and the detection limit was found as 0.167 µM in pH 4.7 acetate buffer solution. Analysis results showed that the proposed electrochemical method could be used for the determination of cefpirome in human urine samples. A linear relationship has been obtained in the concentration range of 2-10 µM. At the same time, the detection limit was found as 0.101 µM for cefpirome in human urine. Moreover, to check the selectivity of the proposed method, the effect of some interference species, including ascorbic acid, uric acid, dopamine, glucose, 〖"Na" 〗^"+" , "K" ^"+" , 〖"Ca" 〗^"+2" , 〖"NO" 〗_"3" ^"-" , have also been investigated. As a result, a simple, sensitive, reproducible, no time-consuming, and more environmentally friendly method was developed when compared to the literature studies.

Viruses are the main pathogenic substances that cause severe diseases in humans and other living things. They are among the most common microorganisms, and consequently, antiviral drugs have emerged to prevent and treat viral infections. Antiviral drugs are an essential drug group considering their prescription and consumption rates for different diseases and indications. Therefore, it is crucial to develop accurate and precise analytical methods to detect antiviral drugs in various matrices. Chromatographic techniques are used frequently for the quantification purpose since they allow simultaneous determination of antivirals. Electrochemical methods have also gained importance since the analysis can be performed quickly without the need for pretreatment. Spectrophotometric and spectrofluorimetric methods are used because they are simple, inexpensive, and less time-consuming methods. The purpose of this review is to present an overview of the analysis of currently used antiviral drugs from 2010 to 2021. Since studies on antiviral drugs are numerous, selected publications were reviewed in this article. The analysis of antiviral drugs was divided into three main groups: chromatographic, spectrometric, and electrochemical methods which were applied to different matrices, including pharmaceutical, biological, and environmental samples.

A sandwich-type electrochemical aptasensor was designed for sensitive detection of leptin in biological samples, including human serum and human plasma. The developed aptasensor was produced by electrodeposition of gold nanoparticles on a screen-printed electrode modified with zinc oxide nanoparticles. The synergy effect of zinc oxide and gold nanoparticles improved the electrocatalytic activity of the aptasensor. The obtained high surface area allowed more aptamer molecules to be loaded on the electrode surface. Signal amplification significantly increases the detection sensitivity of a developed biosensor. Although the use of nanomaterials is the most preferred detection tool for this purpose, as an alternative, enzyme-catalyzed signal amplification is widely used in the construction of a biosensor due to its specificity and high catalytic efficiency. Therefore, both nanomaterial-supported and an alkaline phosphatase-based aptasensor design were developed, which can produce in situ electroactive product by enzymatic hydrolysis of the inactive substrate to achieve a higher signal-to-background ratio. Under optimal conditions, the developed aptasensor exhibited a wide linear concentration range from 0.01 pg mL

Abstract: Mepivacaine, an amide-type local anesthetic drug widely used in regional anesthesia, was studied by some aspects such as electrochemical behavior, mechanism illumination, and analytical applications by cyclic voltammetry (CV) and different pulse voltammetry (DPV) methods. In this study, a novel, fast, simple, portable, and the inexpensive electrochemical sensor was developed for the determination of mepivacaine. This study was carried out by mepivacaine anodic direction detection for the first time. The modified sensor was fabricated with silver nanoparticles (AgNP) and multiwalled carbon nanotubes paste electrode (MWCNTPE) by using the drop-dry method. Different experimental parameters, such as pulse amplitude, step potential, and scanning rate in the DPV application module, were optimized. Under optimal operation conditions, the limit of detection (LOD) as low as 31 μg L-1 was found over the dynamic range (0.1–8.0 mg L-1). In contrast to its high response towards mepivacaine, the DPV exhibits negligible responses on modified AgNP/MWCNTPE when exposed to interfering species such as dopamine, uric acid, glucose, ascorbic acid, and some heavy metals. Exceptionally, the proposed DPV method on modified AgNP/MWCNTPE was successfully applied to pharmaceutical dosage form and synthetic human serum with a low relative standard deviation (RSD) of 1.35% and 2.02%, respectively. background: In this study, a novel, fast, simple, portable, and inexpensive electrochemical sensor was developed for the determination of mepivacaine. objective: This study was carried out by mepivacaine anodic direction detection for the first time. The modified sensor was fabricated with silver nanoparticles (AgNP) and multiwalled carbon nanotubes paste electrode (MWCNTPE) by using drop-dry method. result: Under optimal operation conditions, the limit of detection (LOD) as low as 31 μg L-1 was found over the dynamic range (0.1–8.0 mg L-1).

Interactive association of an antifungal drug, climbazole (CBZ) with the carrier protein in bovine circulation, bovine serum albumin (BSA) was explored by fluorescence and absorption spectroscopy along with in silico techniques. The fluorescence and absorption spectral alterations of the protein upon addition of CBZ affirmed the complex foration between CBZ and BSA. The inverse temperature dependence behaviour of the K

In this study, the interaction between the phosphodiesterase-3 enzyme inhibitor drug milrinone and biomolecules was investigated by electrochemical, fluorescence spectroscopy, and molecular docking studies for the first time. The interaction between milrinone and biomolecules was investigated according to the decrease in deoxyguanosine oxidation signals of milrinone and calf thymus double-stranded deoxyribonucleic acid (ct-dsDNA) by cyclic voltammetry and differential pulse voltammetry. In fluorescence spectroscopy studies, a competitive study was conducted on ct-dsDNA by adding a well-known fluorescent methylene blue and ct-dsDNA solution. The fluorescent results showed that milrinone had a higher affinity for ct-dsDNA binding compared to methylene blue. Interaction studies show that milrinone binds to ct-dsDNA via a groove-binding mode, and the binding constant values ​​were calculated as 4.27 × 106 M−1 and 6.03 × 104 M−1 at 25 °C, based on cyclic voltammetry and spectroscopic results, respectively. As a result of the interaction of human serum albumin and milrinone, the binding coefficient was calculated as 4.11 × 106 M−1 by cyclic voltammetry. In addition, experimental results were confirmed by obtaining information about the possible spatial structure of the aggregate formed through theoretical calculations based on energy minimization for milrinone- ct-dsDNA and milrinone-human serum albumin mixtures with molecular insertion.

© 2022 Elsevier B.V.This study examines the interaction between pyrimidine nucleoside analogue azacytidine, an anti-leukemic drug, and DNA by employing electrochemical, UV–vis spectroscopy, fluorescence spectroscopy and molecular docking techniques. In the electrochemical technique, azacytidine and dsDNA interaction was investigated in two different ways: (1) in solution and (2) with a biosensor using differential pulse voltammetry (DPV) at a glassy carbon electrode. The interaction between azacytidine and dsDNA at increasing interaction times was investigated in line with the changes in adenine and guanine oxidation signals. In addition, interaction studies of polyguanine-azacytidine and polyadenine-azacytidine were performed with DPV. The binding constant values were calculated as 2.420 × 104 M−1 and 3.266 × 104 M−1 at 25 °C using UV and fluorescence spectroscopy, respectively. In conclusion, based on electrochemical and spectroscopic methods as well as molecular docking studies, it was predicted that azacytidine can bind to dsDNA via groove binding.

This study is designed to investigate the interaction of phenylpiperidine derivative drug paroxetine, which is an effective serotonin reuptake inhibitor and biomolecules through electrochemical, fluorescence spectroscopy, and molecular docking methods. The interaction between paroxetine and biomolecules was investigated by differ-ential pulse voltammetry according to the decrease in deoxyguanosine anodic oxidation signal of double -stranded calf thymus DNA. Fluorescence spectroscopy studies were performed by titrating paroxetine against double-stranded calf thymus DNA solution at four different temperatures. The fluorescent results showed that paroxetine had a great affinity to bind with double-stranded calf thymus DNA. Interaction studies demonstrate that paroxetine binds to double-stranded calf thymus DNA via intercalation binding mode, and the binding constant values were calculated as 7.24 x 104 M-1 and 1.52 x 104 M-1 at 25 degrees C, based on voltammetric and spectroscopic results, respectively. Moreover, with the aim of elucidating the interaction mechanism between paroxetine and double-stranded calf thymus DNA, electrochemical and fluorescence spectroscopy studies along with molecular docking analysis were made.

Interaction of two broadly used herbicides, aclonifen (ACF) and bifenox (BIF) with the major transporter in human circulation, human serum albumin (HSA) were examined using fluorescence and absorption spectral measurements combined with in silico analyses. Assessment of the fluorescence and absorption spectral results affirmed the complexation between ACF/BIF and HSA. Increase in the K

The aim of this study is to develop a selective liquid chromatographic method for the simultaneous determination of tamsulosin HCl and dutasteride which are used for prostate treatment, in the context of an analytical column that is packed with superficially porous particles. Therefore, compositions of the mobile phase were determined for the best separation of these compounds. For this reason, experimental conditions such as varied pH values of buffer solution, temperature of the column, additives, flow rate of mobile phase and different buffer solutions were optimized. As the final condition, Kinetex C 18 analytical column (150 × 4.6; 5 µm) (Phenomenex, USA) and an acetonitrile/water 60: 40 (v/v), 0.1% o-phosphoric acid (pH adjusted to 7.0 using 5 M with NaOH) as a mobile phase are used for the best chromatographic separation. The separation was carried out at 45 °C column temperature with detection at 220 nm, and rilpivirine was chosen as an internal standard. As a result, the proposed method under optimum conditions is easy of application, rapid, precise, sensitive, accurate and fully validated. Furthermore, there is no need for time-consuming sample preparation technique, and because of this reason, it can be applied to quality control laboratories simply. Also, the optimized method can be successfully applied for the in vitro biological samples.

Combined therapy for HIV treatment shows superior efficacy in comparison to single therapy. Furthermore, the separation and determination of the combined dosage forms hold a significant place in the pharmaceutical industry. Not only reverse phase high-performance liquid chromatography (HPLC) but also hydrophilic interaction liquid chromatography (HILIC) can be used for these purposes. Contrary to conventional RP systems, HILIC may be an alternative for the analysis of polar substances. The aim of this study was the step-by-step development of a simple, rapid, and reliable method for the simultaneous determination of antiviral compounds from their marketed formulation (Trizivir). In order to achieve this goal, various mobile phase systems, buffer types, and concentrations were prepared to provide an appropriate separation. Different types of columns were tested to find the best resolution and high efficiency for the studied compounds. The proposed method provided a simple procedure for the simultaneous analysis of abacavir, lamivudine, and zidovudine in their pharmaceutical preparation within approximately 2 min using the conventional HPLC system. The developed method was fully validated according to the International Council for Harmonisation guidelines from the viewpoint of selectivity, sensitivity, precision, accuracy, linearity, limit of detection, and quantification.

Molecularly imprinted polymers (MIPs) are biomimetic recognition elements developed for affinity chromatography, sensorics, and potential substitutes of antibodies in therapy. They are prepared by polymerizing one to six monomers in the presence of the target analyte followed by the formation of “paratope-analog” binding sites by the removal of the template from the polymeric scaffold. Electrochemical methods allow for the straightforward synthesis by electropolymerization, template removal by electro-elution, and readout of molecularly imprinted polymers. A wide range of MIP-based electrochemical sensors for low-molecular weight substances, biopolymers as well as cells and viruses have been developed within the past 20 years. All types of nanomaterials have been successfully integrated into the MIP-layer, to enhance the sensitivity. Quantum dots are mostly used in electrochemical sensing to increase the electroactive surface and found limited application as “active” components in (photo) electrochemical MIP-sensors. Integration of quantum dots requires sophisticated preparation procedures, and it is seldom justified by the analytical performance in real samples.

In recent years, we have witnessed an increasing rate of research interest for the polymers that are highly efficient, eco-friendly, and cost-effective materials which also possess multiple physical properties such as conductivity, optical properties, mechanical stability, and surface defect-free films. Quantum dot (QD) and polymer composites exhibit intriguing electronic transitions that resemble single atom behavior because these type of polymers can be coupled with QDs, which are nanocrystals made of semiconductors. QDs are widely used in the fields of analytical chemistry, bioanalysis, and optoelectronics due to their unique, size-tunable electronic, and optical properties. The studies of nanocomposites associated with QDs and polymers, in general, use the QD nanocrystals as the energy donor, and the polymers molecules as acceptors. Electrochemical methods based on QDs/polymers nanocomposites provide significant detection methods that are sensitive, rapid, and low cost. In this chapter, we mainly focus and concentrate on the methods using nanocomposites based on QDs and different types of polymers such as conducting and molecularly imprinted polymers. Using QDs and different types of polymers, electrochemical sensors for different compounds detection and determination of pharmaceuticals, biological samples, and environmental samples are generated. The information about the structures of polymers and examples for the applications of QDs/polymer nanocomposite in the fields of diagnostics and bioanalytics are also summarized in this chapter.

Biosensors are very popular systems in several fields including medical, clinical, environment, food-agriculture, security, and forensic sciences. They also require interdisciplinary work that combines biology, analytical chemistry, physics, and bioelectronics. A biosensor is a device that includes a biological recognition element connected or integrated into a transducer. Although different methods are used as transducers, electrochemical techniques are often preferred as good alternative due to their simplicity, low cost, fast response time, and miniaturization. Nanotechnology is used to make more sensitive analysis with electrochemical methods. Many nanomaterials are integrated with electrochemical transducers and one of the most current among these is quantum dots, which are nanometer-sized semiconductor crystals. The final part of the “Electroanalytical Applications of Quantum Dot Based Biosensors” book summarizes the importance of quantum dots for electrochemical biosensors in terms of synthesis, integration into electrochemical techniques, and usage with other materials and also explains the near future expectations for quantum dots.

Quantum dots (QDs) refer to quantum confinement of electrons and hole carriers at dimensions smaller than the Bohr radius. These fluorescent particles have typical dimensions ranging from 1 to 10 nm. There exists redshift in the fluorescence emission peak with respect to the increase in QD size. This chapter encompasses synthetic methods of QDs in terms of hydrolysis, sol-gel, hydrothermal/solvo thermal, exfoliation process, hydrothermal, microwave-hydrothermal synthesis, laser ablation, etc. A number of characterization methods of QDs such as photoluminescence (PL), UV/vis absorption and fluorescence spectroscopy, X-ray photoemission spectroscopy, transmission electron microscopy, X-ray diffraction, scanning electron microscopy, atomic force microscopy, and dynamic light scattering are also discussed. Moreover, it sheds light on the classification of QDs and their applications.

Citalopram (CIT) and its S-enantiomer, escitalopram (ESC), are antidepressants belonging to the class called selective serotonin reuptake inhibitors and have many different pharmacological and biological properties. Understanding the interaction mechanism of small drug molecules with DNA both helps in the development of new DNA-targeted drugs and provides more in-depth knowledge for controlling gene expression. In this study, the interaction of CIT and ESC with double-stranded calf thymus DNA (ct-dsDNA) was investigated for the first time. Spectrofluorometric, liquid chromatographic, and voltammetric response profiles of drugs and ct-dsDNA at different concentrations showed DNA-drug complex formation. Calculated binding constants were greater with all three techniques for ESC compared to CIT and were of the order of 103-104, which is in accordance with those of well-known groove binders. The results also showed the significant effect of chirality on complex formation. The thermodynamic parameters, including free energy change (ΔG < 0) and enthalpy change (ΔH < 0) obtained at different temperatures, indicated that complex formation was mainly driven by hydrogen bonding and van der Waals forces for both drugs. The results of this study may enhance the understanding of the interaction between CIT or ESC and ct-dsDNA and can be considered as the pioneer for future studies to uncover possible hidden phenotypes of these compounds.

A new capillary electrophoresis method has been developed to analysis of paracetamol (PAR), caffeine (CAF) and codeine (COD) phosphate from pharmaceutical dosage forms. Good results were obtained by using a background electrolyte solution consist of 25 mM (pH 8.5) phosphate buffer solution containing 10% methanol. The separation was performed through an uncoated fused-silica capillaries (50 mu m internal diameter, 56 cm total length, 47.5 cm effective length) at 25 degrees C with the application of 10 seconds of hydrodynamic injection at 40 mbar pressure and a potential of 27 kV. Detection wavelength was chosen 210 nm. Under optimum conditions, the migration times were found 4.427 min for PAR, 3.952 min for CAF, and 3.253 min for COD-phosphate. Linearity ranges were determined 99.72 - 1994.40 mu g mL(-1) for PAR, 5.75 - 115.04 mu g mL(-1) for CAF and 1.84 - 36.80 mu g mL(-1) for COD-phosphate for the method. Limit of detections were found 0.724 mu g mL-1 for PAR, 0.533 mu g mL(-1) for CAF and 0.263 mu g mL(-1) for COD-phosphate in this study. Also, limit of quantitations were found 2.415 mu g mL(-1) for PAR, 1.776 mu g mL(-1) for CAF and 0.877 mu g mL(-1) for COD-phosphate. According to the obtained results, the method is sensitive, specific and repeatable to analysis of PAR, CAF and COD-phosphate.

Background: Allergic rhinitis, acute nasal congestion and sinusitis are one of the most common health problems and have a major effect on the quality of life. Several medications are used to improve the symptoms of such diseases in humans. Pharmaceutical pomade form containing Ephedrine (EPD) HCl, Naphazoline (NPZ) HCl, Antazoline (ANT) HCl, and Chlorobutanol (CLO) is one of them. Objective: For these reasons, this study includes the development of spectrophotometric and chromatographic methods for the determination of EPD HCl, NPZ HCl, ANT HCl, and CLO active agents in the pharmaceutical pomade. Method: In the spectrophotometric method, third-order derivative of the amplitudes at 218 nm n=5 and the first-order derivative of the amplitudes 254 nm n=13 was selected for the determination of EPD, ANT, respectively while NPZ was determined by the second derivative at 234 nm and n=21. Colorimetric detection was applied for assay analysis of CLO at 540 nm. Furthermore, a reverse phase high performance liquid chromatographic (RP- HPLC) method has been developed and optimized by using Agilent Zorbax Eclipse XDB C18 (75 mm x 3.0 mm, 3.5μm) column. The column temperature was 40°C, binary gradient elution was used and the mobile phase consisted of 15 mM phosphate buffer in distilled water (pH 3.0) and methanol, and the flow rate was 0.6 mL min-1 and the UV detector was detected at 210 nm. The linear operating range was obtained as 11.97-70, 0.59-3, 2.79-30, and 2.92-200 μg mL-1 for EPD HCl, NPZ HCl, ANT HCl, and CLO respectively. Results: The LOD values were found to be 3.95, 0.19, 0.92 and 0.96 μg mL-1 for EPD HCl, NPZ HCl, ANT HCl, and CLO in the spectrophotometric method, respectively. The linear ranges in the RP-HPLC method were 8.2-24.36 μg mL-1, 0.083 - 0.75 μg/mL, 2.01-7.5 μg mL-1 and 2.89-24.4 μg mL-1 for EPD HCl, NPZ HCl, ANT HCl, and CLO, respectively. The LOD values in the validation studies were 2.7, 0.025, 0.66 and 0.86 μg mL-1 for EPD HCl, NPZ HCl, ANT HCl, and CLO in RP-HPLC method respectively. Conclusion: The results of the spectrophotometric and chromatographic methods were compared and no differences were found between the two methods.

The excessive use of pesticides in agricultural or non-agricultural fields causes the emergence of environmental and human health problems. Therefore, there is a need to develop simple, fast, sensitive, selective, and low-cost methods for analyzing pesticides from different matrices. Although many analysis methods have been developed to determine pesticides, nanomaterial-based electroanalytical methods offer numerous advantages such as rapid and low cost of analysis, low sample volume requirement, field deployability, and miniaturization to improve the performance of the developed methods. Among different nanomaterials, bimetallic nanomaterials such as gold, platinum, palladium, nickel, and iron-based nanomaterials in combination with other metals have been extensively used as electrode modification agents due to their electrocatalytic characteristics and the synergistic effect of two metals. In this review, firstly, the basic information of pesticides and bimetallic nanomaterials was summarized. Properties, synthesize, and architectures of bimetallic nanomaterials and their nanocomposites were explained in detail. Current applications and utilization of bimetallic nanomaterials for pesticides detection were reviewed by selected studies with working range, the limit of detection, sensitivity, analytical application, and some experimental conditions. In conclusion, the current challenges and future trends for analyzing pesticides based on electroanalytical methods combined with bimetallic nanomaterials were highlighted.

Using various methods and substances for improving performance in sports is described as doping. Doping has always been a critical issue in terms of ethical and medical reasons. In this regard, the World Anti-Doping Agency (WADA) is making significant efforts. Anabolic agents (androsterone, testosterone, oxymetholone, clenbuterol, etc.), hormones, and metabolic modulators (raloxifene, meldonium, theophylline etc.) are prohibited by WADA. Therefore, sensitive and selective determination of these substances in biological and pharmaceutical samples is highly significant. Electroanalytical techniques stand out as sensitive, reliable, fast, and eco-friendly options over other methods. Nanomaterials are stable, catalytic, and easily applicable modification materials. In this context, numerous nanomaterials are used to enhance the performance of the electrochemical sensors. This review examines the latest studies between 2011 and 2021 based on the nanomaterial-based electrochemical sensors as highly sensitive, selective, user-friendly, low-cost, and rapid tools for the determination of selected prohibited substances (hormones, metabolic modulators, and anabolic agents) in biological, pharmaceutical and food samples.

In this work, a novel multi-purpose amperometric nanobiosensor based on tyrosinase enzyme for the determination of phenolic compounds, catechol, epinephrine, and norepinephrine, was developed. This novel nanobiosensor was prepared from Tyrosinase enzyme immobilization in poly (3,4 ethylenedioxythiophene) nanoparticles decorated graphene quantum dots platform via crosslinking with glutaraldehyde. Parameters that can affect biosensing, such as graphene quantum dots, poly (3,4 ethylenedioxythiophene) nanoparticles, tyrosinase quantities, pH, and temperature, were optimized. Under optimized conditions, determination of phenolic compounds was achieved in the range 0.005−11 μM for catechol, 0.2−12 μM for epinephrine, and 0.1–2.5 μM for norepinephrine. Limit of detection values were found as 0.002 μM, 0.065 μM, 0.035 μM for catechol, epinephrine, and norepinephrine, respectively, with acceptable repeatability and reproducibility results. Moreover, the developed nanobiosensor was further successfully utilized to follow inhibition of tyrosinase by a non-steroidal anti-inflammatory drug, diclofenac, with different incubation times and concentration levels. Hence, I50 was reported as 4.87 mM diclofenac. The optimized biosensor was also applied for the detection of epinephrine and norepinephrine in pharmaceutical dosage forms, catechol from human serum.

In this paper, we report a fluorescent sensor array approach for the urinary detection of a prohibited substance in sports, meldonium. Four chemosensors with ethidium bromide scaffolds were employed in this method. The interaction between meldonium and chemosensors was investigated by different techniques, such as ultraviolet-visible absorption and fluorescence spectroscopy, nuclear magnetic resonance, and mass spectrometry. Molecular dynamics simulation was also used to elucidate and support the interaction mechanisms between meldonium and the chemosensors. Differential responses obtained from the sensor array enabled the qualitative and quantitative analyses of meldonium with low error values. This method was able to detect and quantify meldonium at the nM level, fulfilling the requirements of minimum performance defined by the World Anti-Doping Agency. © The Royal Society of Chemistry 2020., 117Z185 Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, The authors acknowledge the Scientific and Technological Research Council of Turkey (TUBITAK, project no.: 117Z185) for financial support. The authors also specially thank Dr Yesim Somay Selbes from the Turkish Doping Control Center and Prof. Dr Zeynel Seferoglu from Gazi University for their support.

The development of agriculture is closely related to the use and application of pesticides in order to improve products. Excessive use of pesticides is indeed very dangerous to essential pests and it has a potential negative effect over human health, pollution of soil and waters. For these reasons, in this study, a dilute-and-shoot sample preparation procedure for simultaneous determination of three pesticides (buprofezin, dinobuton and chlorothalonil) was developed and validated for the first time combined with high-performance liquid chromatography–diode-array detector method in urine, serum, tomato, soil, commercial dosage form and water samples. Also, the degradation and behaviour of these pesticides were investigated under different conditions in the environment. HPLC analysis was performed with Kinetex C18 (150 mm × 4.6 mm; 5 μm) column with 1 mL min−1 flow rate of mobile phase which consisted of acetonitrile/buffer in the ratio of 75:25 (v/v) at 25.0°C. Calibration graphs showed a good linearity with a coefficient of determination (R2) of at least 0.999 for all analytes. Intraday and interday precisions (expressed as RSD%) were lower than 1.66% for all analytes. The developed method was demonstrated to be sensitive, simple, robust and rapid for the simultaneously determination of analytes in different samples providing recoveries in the range between 92.3% and 109.74%.

This paper represents a comprehensive review about the most recent developments in indium tin oxide (ITO) based electrochemical chemosensors and biosensors. ITO electrode has received increasing attention due to its large potential window and excellent optical properties. It provides electrochemical stability and a low background current and has recently been applied as a working electrode in the electrochemical analysis. The focal point of this paper was based on the sensor applications and properties of modified ITO electrodes in the determination of some biomarkers, pathogens, pesticides, drugs, organic species, and metals, etc. by electrochemical techniques. Experimental conditions and some analytical parameters of the electrode applications were discussed. The future possibilities and prospects of ITO electrodes have been outlined. In this case, there are significant studies to display the powerful ITO sensors for the determination of analytes and this review summarizes the available data on this topic between 2010 and 2021.

A novel, sensitive and simple amperometric biosensor for the determination of catechol and azinphos methyl based on Tyrosinase enzyme inhibition has been developed. The biosensor was prepared from iridium (IV) oxide, Poly (3,4 ethylenedioxythiophene) nanocomposite, and Tyrosinase immobilized by crosslinking with glutaraldehyde in this nanocomposite platform. Biosensor was successfully used for the dual determination of catechol and azinphos methyl using fixed potential amperometry. Biosensor performance was optimized in terms of iridium (IV) oxide, Poly (3,4 ethylenedioxythiophene) and Tyrosinase. The surface morphology of the enzyme electrode was characterized by scanning electrochemical microscopy, atomic force microscopy, cyclic voltammetry and electrochemical impedance. Under optimized conditions, linear relationships were achieved in the range 0.05−10.65 μM for catechol and 10−200 μM for azinphos methyl. Limit of detection was found as 0.017 μM for catechol and 2.964 μM for azinphos methyl with acceptable repeatability and reproducibility. Finally, developed biosensor was successfully applied to the detection of azinphos methyl tap water, waste water, well water, human urine, serum and saliva.

Nowadays, the development of various biosensors as a new generation of analytical instruments is one of the most promising research fields of analytical biology. Among all types of biosensors, enzyme based biosensors have an interesting property, the inherent inhibition phenomena given the enzyme-substrate complex formation. Over the past years, electrochemical enzyme based biosensors have emerged as simple, rapid and ultra-sensitive devices for determination or detection of different compounds in the drugs and food samples. In this review, general views to enzymes related with their history, classification, immobilization, and inhibition information is presented to researchers. Then, a detailed description is provided for enzyme based and electrochemical enzyme based biosensors. Finally, some selected electrochemical enzyme based biosensor studies developed for food and drug analysis are summarized and tabulated.