Analysis of atorvastatin in environmental waters: Validation of an electrochemical molecularly imprinted polymer sensor with application of life cycle assessment.

The widespread presence of pharmaceuticals in wastewater effluents after treatment stands as a significant challenge faced in the field of wastewater management and public health. Governments and the scientific community have worked to meet this urgent need for effective solutions. Nevertheless, the development of detection strategies for pharmaceutical monitorization capable of delivering rapid, on-site, and sensitive responses remains an ongoing necessity. In this work, the performance of a previously developed molecularly imprinted polymer (MIP) based electrochemical sensor for detecting atorvastatin (ATV) in wastewater effluents and surface waters is presented. A simple preconcentration method followed by electrochemical measurements by differential pulse voltammetry (DPV) in 0.1 M phosphate buffer (pH = 7), was implemented. The analytical results were validated with those obtained on a set of 16 water samples by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). Additionally, a life cycle assessment (LCA) was conducted to compare the environmental impact of both methodologies. The results obtained demonstrated that ATV detection using MIP-sensor was reliable when compared to the results found by UHPLC-MS/MS presenting a robust linear correlation coefficient of 0.843. The LCA results show that the novel MIP-sensor technique has lower associated environmental impacts than UHPLC-MS/MS, when the current analytical protocol for pharmaceuticals detection is applied. These findings highlight the potential of the developed MIP-sensor as an eco-friendly analytical tool for routine analysis and point-of-care monitoring of ATV in WWTP wastewater and surface water samples.

Electrochemical Chemically Based Sensors and Emerging Enzymatic Biosensors for Antidepressant Drug Detection: A Review.

Major depressive disorder is a widespread condition with antidepressants as the main pharmacological treatment. However, some patients experience concerning adverse reactions or have an inadequate response to treatment. Analytical chromatographic techniques, among other techniques, are valuable tools for investigating medication complications, including those associated with antidepressants. Nevertheless, there is a growing need to address the limitations associated with these techniques. In recent years, electrochemical (bio)sensors have garnered significant attention due to their lower cost, portability, and precision. Electrochemical (bio)sensors can be used for various applications related to depression, such as monitoring the levels of antidepressants in biological and in environmental samples. They can provide accurate and rapid results, which could facilitate personalized treatment and improve patient outcomes. This state-of-the-art literature review aims to explore the latest advancements in the electrochemical detection of antidepressants. The review focuses on two types of electrochemical sensors: Chemically modified sensors and enzyme-based biosensors. The referred papers are carefully categorized according to their respective sensor type. The review examines the differences between the two sensing methods, highlights their unique features and limitations, and provides an in-depth analysis of each sensor.

Computational Modelling and Sustainable Synthesis of a Highly Selective Electrochemical MIP-Based Sensor for Citalopram Detection.

A novel molecularly imprinted polymer (MIP) has been developed based on a simple and sustainable strategy for the selective determination of citalopram (CTL) using screen-printed carbon electrodes (SPCEs). The MIP layer was prepared by electrochemical in situ polymerization of the 3-amino-4 hydroxybenzoic acid (AHBA) functional monomer and CTL as a template molecule. To simulate the polymerization mixture and predict the most suitable ratio between the template and functional monomer, computational studies, namely molecular dynamics (MD) simulations, were carried out. During the experimental preparation process, essential parameters controlling the performance of the MIP sensor, including CTL:AHBA concentration, number of polymerization cycles, and square wave voltammetry (SWV) frequency were investigated and optimized. The electrochemical characteristics of the prepared MIP sensor were evaluated by both cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. Based on the optimal conditions, a linear electrochemical response of the sensor was obtained by SWV measurements from 0.1 to 1.25 µmol L-1 with a limit of detection (LOD) of 0.162 µmol L-1 (S/N = 3). Moreover, the MIP sensor revealed excellent CTL selectivity against very close analogues, as well as high imprinting factor of 22. Its applicability in spiked river water samples demonstrated its potential for adequate monitoring of CTL. This sensor offers a facile strategy to achieve portability while expressing a willingness to care for the environment.

Electropolymerized, Molecularly Imprinted Polymer on a Screen-Printed Electrode-A Simple, Fast, and Disposable Voltammetric Sensor for Trazodone.

In recent years, analytical chemistry has been facing new challenges, particularly in developing low-cost, green, and easy-to-reproduce methods. In this work, a simple, reproducible, and low-cost electrochemical (voltammetric) molecularly imprinted polymer (MIP) sensor was designed specifically for the detection of trazodone (TZD). Trazodone (TZD) is an antidepressant drug consumed worldwide since the 1970s. By combining electropolymerization (surface imprinting) with screen-printed electrodes (SPCEs), the sensor is easy to prepare, is environmentally friendly (uses small amounts of reagents), and can be used for in situ analysis through integration with small, portable devices. The MIP was obtained using cyclic voltammetry (CV), using 4-aminobenzoic acid (4-ABA) as the functional monomer in the presence of TZF molecules in 0.1 M HCl. Non-imprinted control was also constructed in the absence of TZD. Both polymers were characterized using CV, and TZD detection was performed with DPV using the oxidation of TZD. The polymerization conditions were studied and optimized. Comparing the TZD signal for MIP/SPCE and NIP/SPCE, an imprinting factor of 71 was estimated, indicating successful imprinting of the TZD molecules within the polymeric matrix. The analytical response was linear in the range of 5-80 µM, and an LOD of 1.6 µM was estimated. Selectivity was evaluated by testing the sensor for molecules with a similar structure to TZD, and the ability of MIP/SPCE to selectively bind to TZD was proven. The sensor was applied to spiked tap water samples and human serum with good recoveries and allowed for a fast analysis (around 30 min).

A simple electrochemical detection of atorvastatin based on disposable screen-printed carbon electrodes modified by molecularly imprinted polymer: Experiment and simulation.

Atorvastatin (ATV) is a statin member consumed in high quantities worldwide. In response to that, the occurrence of ATV in environmental waters has become a reality, highlighting the need of rapid and sensitive analytical devices for its monitoring. In this work, the first electrochemical molecularly imprinted polymer (MIP) sensor for the detection of ATV in water samples is presented. Computational studies were conducted based on quantum mechanical (QM) calculations and molecular dynamics (MD) simulations for rational selection of a suitable functional monomer and to study in detail the template-monomer interaction, respectively. The sensor was prepared by electropolymerisation of the selected 4-aminobenzoic acid (ABA) monomer with ATV, acting as template, on screen printed carbon electrode (SPCE). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques were applied to characterise the modified electrode surfaces. The quantitative measurements were carried out with differential pulse voltammetry (DPV) in 0.1 M phosphate buffer (pH = 7). After investigation and optimisation of important experimental parameters, a linear working range down to 0.05 µmol L-1 was determined with a correlation coefficient of 0.9996 and a limit of detection (LOD) as low as 0.049 µmol L-1 (S/N = 3). High sensitivity and selectivity of the prepared sensor were demonstrated with the ability to recognise ATV molecules over its closer structural analogues. Moreover, the sensor was quickly and successfully applied in spiked water samples, proving its potential for future on-site monitoring of ATV in environmental waters.

Low Cost, Easy to Prepare and Disposable Electrochemical Molecularly Imprinted Sensor for Diclofenac Detection.

In this work, a disposable electrochemical (voltammetric) molecularly imprinted polymer (MIP) sensor for the selective determination of diclofenac (DCF) was constructed. The proposed MIP-sensor permits fast (30 min) analysis, is cheap, easy to prepare and has the potential to be integrated with portable devices. Due to its simplicity and efficiency, surface imprinting by electropolymerization was used to prepare a MIP on a screen-printed carbon electrode (SPCE). MIP preparation was achieved by cyclic voltammetry (CV), using dopamine (DA) as a monomer in the presence of DCF. The differential pulse voltammetry (DPV) detection of DCF at MIP/SPCE and non-imprinted control sensors (NIP) showed an imprinting factor of 2.5. Several experimental preparation parameters were studied and optimized. CV and electrochemical impedance spectroscopy (EIS) experiments were performed to evaluate the electrode surface modifications. The MIP sensor showed adequate selectivity (in comparison with other drug molecules), intra-day repeatability of 7.5%, inter-day repeatability of 11.5%, a linear range between 0.1 and 10 µM (r2 = 0.9963) and a limit of detection (LOD) and quantification (LOQ) of 70 and 200 nM, respectively. Its applicability was successfully demonstrated by the determination of DCF in spiked water samples (river and tap water).

Organochlorine pesticide analysis in milk by gas-diffusion microextraction with gas chromatography-electron capture detection and confirmation by mass spectrometry.

Organochlorine pesticides (OCPs) are synthetic compounds less used nowadays due to their toxicity combined with slow degradation which leads to accumulation in the environment. Gas-diffusion microextraction (GDME) was employed prior to gas chromatography with electron capture detection (GC-ECD) and mass spectrometry (GC-MS). For the first time, the low-cost, eco-friendly GDME system was used to extract the OCPs directly from milk samples and associated with GC-ECD. Parameters that affect GDME's performance (extract volume, extraction time, and temperature) were optimized. The calibration curves of all OCPs (α- and ß-hexachlorocyclohexane, lindane, hexachlorobenzene, p,p'-DDE, aldrin, dieldrin, and α-endosulfan) had coefficients of determination (r2) ranging from 0.991 to 0.995, and limits of detection (LODs) values ranging from 3.7 to 4.8 µg L-1. This method also provided satisfactory values for precision with relative standard deviations (RSDs) lower than 10% and recoveries above 90%. As a proof-of-concept, several commercial milk samples were analyzed, aldrin was found in one of them but below the maximum residue limits.

Molecularly imprinted polymer-based electrochemical sensors for environmental analysis.

The ever-increasing presence of contaminants in environmental waters is an alarming issue, not only because of their harmful effects in the environment but also because of their risk to human health. Pharmaceuticals and pesticides, among other compounds of daily use, such as personal care products or plasticisers, are being released into water bodies. This release mainly occurs through wastewater since the treatments applied in many wastewater treatment plants are not able to completely remove these substances. Therefore, the analysis of these contaminants is essential but this is difficult due to the great variety of contaminating substances. Facing this analytical challenge, electrochemical sensing based on molecularly imprinted polymers (MIPs) has become an interesting field for environmental monitoring. Benefiting from their superior chemical and physical stability, low-cost production, high selectivity and rapid response, MIPs combined with miniaturized electrochemical transducers offer the possibility to detect target analytes in-situ. In most reports, the construction of these sensors include nanomaterials to improve their analytical characteristics, especially their sensitivity. Moreover, these sensors have been successfully applied in real water samples without the need of laborious pre-treatment steps. This review provides a general overview of electrochemical MIP-based sensors that have been reported for the detection of pharmaceuticals, pesticides, heavy metals and other contaminants in water samples in the past decade. Special attention is given to the construction of the sensors, including different functional monomers, sensing platforms and materials employed to achieve the best sensitivity. Additionally, several parameters, such as the limit of detection, the linear concentration range and the type of water samples that were analysed are compiled.

Evaluation of the QuEChERS and magnetic micro dispersive solid-phase extraction of brominated flame retardants in red fruits with determination by GC/MS.

A sample preparation method, QuEChERS extraction combined with a magnetic micro dispersive solid phase extraction (MµdSPE), was optimized and evaluated for the trace analysis of 9 brominated flame retardants in red fruit samples (strawberries, blueberries, and raspberries) using gas chromatography-mass spectrometry. Magnetic nanomaterials were used as sorbents providing an extraction of the target compounds. Linearity was established for all the analytes (from 10 to 200 µg kg-1). Seven concentration levels were analyzed with three measurements at each concentration. Linear responses (R2 > 0.99) were obtained, recoveries of all target analytes were within the range of 65-141%, relative standard deviations were <20% at all three spiking levels, while intraday and interday precisions were below 20%. This study demonstrated that the new sample preparation with magnetic nanoparticles could potentially be expanded to extract and pre-concentrate the BFRs in different red fruit samples. The method has been successfully applied to study BFRs in 12 samples from conventional and organic farming.

Electrochemical sensing of the thyroid hormone thyronamine (T0AM) via molecular imprinted polymers (MIPs).

Recent studies have shown that besides the well-known T3 (triiodothyronine) and T4 (thyroxine) there might be other important thyroid hormones, in particular T0AM (thyronamine) and T1AM (3-iodothyronamine). The absence of a large number of studies showing their precise importance might be explained by the limited number of analytical methodologies available. This work aims to show an electroanalytical alternative making use of electropolymerized molecularly imprinted polymer (MIPs). The MIPs' polymerization is performed on the surface of screen-printed carbon electrodes (SPCEs), using 4-aminobenzoic acid (4-ABA) as the building and functional monomer and the analyte T0AM as the template. The step-by-step construction of the SPCE-MIP sensor was studied by cyclic voltammetry (CV) and by electrochemical impedance spectroscopy (EIS). After optimization, by means of square-wave voltammetry, the SPCE-MIP showed suitable selectivity (in comparison with other thyroid hormones and catechol amines), repeatability (intra-day of 3.9%), a linear range up to 10 µmol L-1 (0.23 × 103 µg dL-1) with an r2 of 0.998 and a limit of detection (LOD) and quantification (LOQ) of 0.081 and 0.27 µmol L-1 (1.9 and 6.2 µg dL-1), respectively.

MIP-graphene-modified glassy carbon electrode for the determination of trimethoprim.

A novel sensitive electrochemical sensor was developed by electropolymerization of pyrrole (PY) and molecularly imprinted polymer (MIP) which was synthesized onto a glassy carbon electrode (GCE) in aqueous solution using cyclic voltammetry in the presence of Trimethoprim (TMP) as template molecules. Furthermore, a previous electrode modification was performed by deposition of a suspension of graphene on the electrode's surface. The performance of the imprinted and non-imprinted (NIP) films was evaluated by impedance spectroscopy (EIS) and cyclic voltammetry (CV) of a ferric solution. The molecularly imprinted film exhibited a high selectivity and sensitivity toward TMP. The sensor presented a linear range, between peak current intensity and logarithm of TMP concentration between 1.0 × 10(-6) and 1.0 × 10(-4)M. The results were accurate (with recoveries higher than 94%), precise (with standard deviations less than 5%) and the detection limit was 1.3 × 10(-7)M. The new sensor is selective, simple to construct and easy to operate. The MIP sensor was successfully applied to quantify TMP in urine samples.

Isolation of phenolic compounds from hop extracts using polyvinylpolypyrrolidone: characterization by high-performance liquid chromatography-diode array detection-electrospray tandem mass spectrometry.

The aim of the present work was the development of a suitable methodology for the separation and determination of phenolic compounds in the hop plant. The developed methodology was based on the sample purification by adsorption of phenolic compounds from the matrix to polyvinylpolypyrrolidone (PVPP) and subsequent desorption of the adsorbed polyphenols with acetone/water (70:30, v/v). At last, the extract was analyzed by HPLC-DAD and HPLC-ESI-MS/MS. The first phase of this work consisted of the study of the adsorption behavior of several classes of phenolic compounds (e.g. phenolic acids, flavonols, and flavanols) by PVPP in model solutions. It has been observed that the process of adsorption of the different phenolic compounds to PVPP (at low concentrations) is differentiated, depending on the structure of the compound (number of OH groups, aromatic rings, and stereochemistry hindrance). For example, within the phenolic acids class (benzoic, p-hydroxybenzoic, protocatechuic and gallic acids) the PVPP adsorption increases with the number of OH groups of the phenolic compound. On the other hand, the derivatization of OH groups (methylation and glycosylation) resulted in a greatly diminished binding. The use of PVPP revealed to be very efficient for adsorption of several phenolic compounds such as catechin, epicatechin, xanthohumol and quercetin, since high adsorption and recovery values were obtained. The methodology was further applied for the extraction and isolation of phenolic compounds from hops. With this methodology, it was possible to obtain high adsorption values (>or=80%) and recovery yield values (>or=70%) for the most important phenolic compounds from hops such as xanthohumol, catechin, epicatechin, quercetin and kaempferol glycosides, and in addition it allows the identification of about 30 phenolic compounds by HPLC-DAD and HPLC-ESI-MS/MS.