Preparation of NiFe2O4/graphene nanocomposite and its application as a modifier for the fabrication of an electrochemical sensor for the simultaneous determination of tramadol and acetaminophen

A green impedimetric aptasensor for non-invasive and high-selective detection of tramadol validated by molecular dynamic simulation

Although the dosage controlling of tramadol (TRA) as a banned deadly drug in human biofluids is medicolegally important a biocompatible method for its high-selective detection with fewer false interferences has been scarcely reported. Herein, a new impedimetric aptasensor is introduced by utilizing the aptamer (Apt) sequence with high affinity to TRA for the first time to non-invasively measure it. An oriented nanolayer of Au nanoparticles (AuNPs) is easily formed on the surface by the electrodeposition technique to high-densely load the Apt and embed the novel aptasensing interface via a user-friendly methodology. The visual interaction of Apt with its target has been explored using molecular dynamic (MD) simulation to confirm how Apt traps TRA in its arm. The aptasensor measured TRA in a concentration range of 50 pM to 1.3 nM with a limit of detection (LOD) of 16.66 pM in buffer. It also rendered good accuracy and recovery for human salivary and urinary analysis. In addition, the greenness profile of the proposed methodology has been validated with two international common indexes. The developed aptasensor promises a reasonable capability for TRA monitoring in real clinical or street narcotic samples according to green analytical chemistry (GAC).

Poly-taurine/poly-L-glutamic acid double-layer coating as potential candidates for surface modification of carbon felt electrode for discrimination and simultaneous detection of morphine and tramadol

An ultrasensitive and reliable electrochemical scaffold was designed for the individual and simultaneous measurement of morphine (Mor) and tramadol (Trm) addictive and illegal drugs, utilizing a cost-effective and flexible carbon felt electrode modified with double-layer poly-taurine/poly-L-glutamic acid (P(Tau)/P(Glu)/CF). It is worth noting that drugs have now become a part of daily life in all societies, and the consumption of tranquilizers and opiates such as Mor and Trm has also increased. Given the frequent co-use of Mor and Trm, accurate and reliable methods for their simultaneous measurement are crucial. Simultaneous diagnostics make the determination more efficient and cost-effective by reducing the need for multiple sensors. Surface modification of CFE was carried out by a green approach, facile and straightforward route by layer-by-layer electropolymerization, forming a thin polymeric film with abundant functional groups responsible for anchoring narcotic drugs. The P(Tau)/P(Glu)/CFE composite showed an exceptionally high rate of active site exposure and proper electrochemical activity, attributed to the synergistic effects of the constituent materials. P(Tau)/P(Glu)/CFE was successfully used to detect saliva, urine, plasma, and body sweat samples with satisfactory recoveries.

A systematic review on electrochemical sensors for the detection of acetaminophen

Considerable progress has been made in the electrochemical determination of acetaminophen (AP) over the past few decades. Nanomaterials or enzymes as electrode modifiers greatly improve the performance of AP electrochemical sensors. This review focuses on the development potential, detection principles and techniques for the electrochemical analysis of AP. In particular, the design and construction of AP electrochemical sensors are discussed from the perspective of non-enzyme materials (such as nanomaterials, including precious metals, transition metals and non-metals) and enzyme substances (such as aryl acylamidase, polyphenol oxidase and horseradish peroxidase). Moreover, the influencing factors for AP electrochemical sensors and the simultaneous detection of AP and other targets are summarized, and the future prospective of AP electrochemical sensors is outlined. This review provides a reference and guidance for the development and application of electrochemical sensors for AP detection.

Comprehensive overview of analytical and bioanalytical methodologies for the opioid analgesics - Tramadol and combinations

Synthetic opioids like Tramadol are used to treat mild to moderate pain. Its ability to relieve pain is about a tenth that of morphine. Furthermore, Tramadol shares similar effects on serotonin and norepinephrine to several antidepressants known as serotonin-norepinephrine reuptake inhibitors (SNRIs), such as venlafaxine and duloxetine. The present review paper discusses the recent developments in analytical methods for identifying drugs in pharmaceutical preparations and toxicological materials, such as blood, saliva, urine, and hair. In recent years, a wide variety of analytical instruments, including capillary electrophoresis, NMR, UV-visible spectroscopy, HPTLC, HPLC, LC-MS, GC, GC-MS, and electrochemical sensors, have been used for drug identification in pharmaceutical preparations and toxicological samples. The primary quantification techniques currently employed for its quantification in various matrices are highlighted in this research.

Sonochemical synthesis of lanthanum ferrite nanoparticle-decorated carbon nanotubes for simultaneous electrochemical determination of acetaminophen and dopamine

A new nanocomposite consisting of lanthanum ferrite nanoparticles (LaFeO3 NPs) integrated with carbon nanotubes (CNTs) was fabricated via facile sonochemical approach. The engineered nanocomposite was applied to simultaneously determine acetaminophen (ACP) and dopamine (DA) in a binary mixture. The LaFeO3 NPs@CNT probe possesses several advantages such as superior conductivity, large surface area, and more active sites, improving its electrocatalytic activity towards ACP and DA. Under optimized conditions, the anodic peak currents (Ipa) linearly increased with increasing concentration of ACP and DA in the range 0.069-210 µM and 0.15-210 µM, respectively. The sensitivity of LaFeO3 NPs@CNTs/glassy carbon electrode (GCE) for detecting ACP and DA is 7.456 and 5.980 μA·μM-1·cm-2, respectively. The detection limits (S/N = 3) for ACP and DA are 0.02 μM and 0.05 μM, respectively. Advantages of LaFeO3 NPs@CNTs/GCE for the detection of ACP and DA include wide linear ranges, low-detection limits, good selectivity, and long-term stability. The as-fabricated electrode was applied to determine ACP and DA in pharmaceutical formulations and human serum samples with recoveries ranging from 97.7 to 103.3% and an RSD that did not exceed 3.7%, confirming the suitability of the proposed sensor for the determination of ACP and DA in real samples. This study not only presents promising opportunities for enhancing the sensitivity and stability of electrochemical sensors used in the detection of bioanalytes but also significantly contributes to the progress of unique and comprehensive biochemical detection methodologies.

An amplified electrochemical sensor employing one-step synthesized nickel-copper-zinc ferrite/carboxymethyl cellulose/graphene oxide nanosheets composite for sensitive analysis of omeprazole

In this work, a signal amplification strategy was designed by the fabrication of a highly sensitive and selective electrochemical sensor based on nickel-copper-zinc ferrite (Ni0.4Cu0.2Zn0.4Fe2O4)/carboxymethyl cellulose (CMC)/graphene oxide nanosheets (GONs) composite modified glassy carbon electrode (GCE) for determination of omeprazole (OMP). The one-step synthesized Ni0.4Cu0.2Zn0.4Fe2O4/CMC/GONs nanocomposite was characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy and X-ray diffraction techniques. Then, the Ni0.4Cu0.2Zn0.4Fe2O4/CMC/GONs/GCE was applied to study the electrochemical behavior of the OMP. Electrochemical data show that the Ni0.4Cu0.2Zn0.4Fe2O4/CMC/GONs/GCE exhibits superior electrocatalytic performance on the oxidation of OMP compared with bare GCE, GONs/GCE, CMC/GONs/GCE and MFe2O4/GCE (M = Cu, Ni and Zn including single, double and triple of metals) which can be attributed to the synergistic effects of the nanocomposite components, outstanding electrical properties of Ni0.4Cu0.2Zn0.4Fe2O4 and high conductivity of CMC/GONs as well as the further electron transport action of the nanocomposite. Under optimal conditions, the Ni0.4Cu0.2Zn0.4Fe2O4/CMC/GONs/GCE offers a high performance toward the electrodetermination of OMP with the wide linear-range responses (0.24-5 and 5-75 μM), lower detection limit (0.22 ± 0.05 μM), high sensitivity (1.1543 μA μM-1 cm-2), long-term signal stability and reproducibility (RSD = 2.54%). It should be noted that the Ni0.4Cu0.2Zn0.4Fe2O4/CMC/GONs/GCE sensor could also be used for determination of OMP in drug and biological samples, indicating its feasibility for real analysis.

A nanoporous gold film sensor modified with polypyrrole/CuO nanocomposite for electrochemical determination of piroxicam and tramadole

In this paper, an electrochemical sensor was developed to determine piroxicam (PX) and tramadole (Tr) based on their enhanced electrochemical responses at the surface of the polypyrrole/CuO nanocomposite-modified nanoporous gold film (NPGF) electrode. The experimental results showed that PX provide an oxidation peak at 0.65 V in pH = 8.0. The DPV results were linearly affiliated on PX concentration within the two closed windows (C1_PX = 0.05-30.0 μM, correlation coefficient of 0.9905, and C2_PX = 50.0-300.0 μM, correlation coefficient of 0.9927). From voltammetric curves, the detection limit (LOD = 3S_b/m) for PX at a surface of PPY-CuO-NPGF electrode was appeared to be 0.01 μM. Furthermore, the ability of PPY-CuO-NPGF electrode for simultaneous measurement of PX and Tr was investigated. The suggested sensor shows a long-time stability, good repeatability, and rapid response in the mixture media of PX and Tr.

Onion-like Carbons Provide a Favorable Electrocatalytic Platform for the Sensitive Detection of Tramadol Drug

This work reports the first study on the possible application of nanodiamond-derived onion-like carbons (OLCs), in comparison with conductive carbon black (CB), as an electrode platform for the electrocatalytic detection of tramadol (an important drug of abuse). The physicochemical properties of OLCs and CB were determined using X-ray diffraction (XRD), Raman, scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), and thermogravimetric analysis (TGA). The OLC exhibits, among others, higher surface area, more surface defects, and higher thermal stability than CB. From the electrochemical analysis (interrogated using cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy), it is shown that an OLC-modified glassy carbon electrode (GCE-OLC) allows faster electron transport and electrocatalysis toward tramadol compared to a GCE-CB. To establish the underlying science behind the high performance of the OLC, theoretical calculations (density functional theory (DFT) simulations) were conducted. DFT predicts that OLC allows for weaker surface binding of tramadol (E _ad = -26.656 eV) and faster kinetic energy (K.E. = -155.815 Ha) than CB (E _ad = -40.174 eV and -305.322 Ha). The GCE-OLC shows a linear calibration curve for tramadol over the range of ∼55 to 392 μM, with high sensitivity (0.0315 μA/μM) and low limit of detection (LoD) and quantification (LoQ) (3.8 and 12.7 μM, respectively). The OLC-modified screen-printed electrode (SPE-OLC) was successfully applied for the sensitive detection of tramadol in real pharmaceutical formulations and human serum. The OLC-based electrochemical sensor promises to be useful for the sensitive and accurate detection of tramadol in clinics, quality control, and routine quantification of tramadol drugs in pharmaceutical formulations.

A bibliometric analysis of graphene in acetaminophen detection: Current status, development, and future directions

Acetaminophen is a widely used analgesic throughout the world. Detection of acetaminophen has particular value in pharmacy and clinics. Electrochemical sensors assembled with advanced materials are an effective method for the rapid detection of acetaminophen. Graphene-based carbon nanomaterials have been extensively investigated for potential analytical applications in the last decade. In this article, we selected papers containing both graphene and acetaminophen. Bibliometrics was used to analyze the relationships and trends among these papers. The results show that the topic has grown at a high rate since 2009. Among them, the detection of acetaminophen by an electrochemical sensor based on graphene is the most important direction. Graphene has moved from being a primary sensing material to a substrate for immobilization of other active ingredients. In addition, the degradation of acetaminophen using graphene-modified electrodes is also an important direction. We analyzed the research history and current status of this topic through bibliometrics. Authors, institutions, countries, and key literature were discussed. We also proposed perspectives for this topic.

A reusable and sensitive electrochemical sensor for determination of idarubicin in environmental and biological samples based on NiFe2O4 nanospheres anchored N-doped graphene quantum dots composite; an electrochemical and molecular docking investigation

An ultrasensitive and selective voltammetric sensor with ultra-trace level detection limit is introduced for idarubicin (IDA) determination in real samples. The as-synthesized nanocomposite was characterized by several techniques, including Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Raman spectroscopy, Energy-dispersive X-ray spectroscopy (EDX), and Field emission scanning electron microscopy (FE-SEM). The electrocatalytic performance of the developed electrode was observed by cyclic voltammetry (CV), differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS), and chronoamperometry. The limit of detection (LOD) of the developed sensor for idarubicin is 1.0 nM, and the response is found to be in the dynamic concentration range of 0.01-1.9 μmol/L in a Britton-Robinson buffer (B-R, pH = 6.0). Moreover, the fabricated electrode illustrated high selectivity with good repeatability and reproducibility for diagnosing idarubicin as an anthracycline antileukemic drug. Furthermore, to evaluate the validity of the recommended method, three real samples, including human plasma, urine, and water samples, were analyzed with satisfactory recovery and compared with high-performance liquid chromatography (HPLC). The minor groove-binding mode of interaction was also supported by docking simulation studies, emphasizing that IDA can bind to ds-DNA preferably and confirmed experimental results. The reduced assay time and the possibility of measuring a single sample with another anticancer drug without any interference are significant advantages compared to the HPLC. The developed and validated sensor could be a valuable point-of-care diagnostic tool for IDA quantification in patients.

Recent Developments in the Sensitive Electrochemical Assay of Common Opioid Drugs

Opioids are a class of drugs used to treat moderate to severe pain and have short-term adverse effects. Nevertheless, they are considered necessary for pain management. However, well-known hazards are connected with an opioid prescription, such as overuse, addiction, and overdose deaths. For example, the death rate from opioid analgesic poisoning in the USA approximately doubled, owing to the overuse and addiction of opioid analgesics. Also, opioids are a very important group of analytes in forensic chemistry, so it is necessary to use reliable, fast, and sensitive analytical tools to determine opioid analgesics. This review focuses on the opioid overdose crisis, the properties of commonly used opioid drugs, their mechanism, effects, and some chromatographic and spectroscopic detection methods are explained briefly. Then most essentially recent developments covering the last ten years in the sensitive electrochemical methods of common opioid analgesics, their innovations and features, and future research directions are presented.

Graphene-Based Electrochemical Sensors for Psychoactive Drugs

Sensors developed from nanomaterials are increasingly used in a variety of fields, from simple wearable or medical sensors to be used at home to monitor health, to more complicated sensors being used by border customs or aviation industries. In recent times, nanoparticle-based sensors have begun to revolutionize drug-detection techniques, mainly due to their affordability, ease of use and portability, compared to conventional chromatography techniques. Thin graphene layers provide a significantly high surface to weight ratio compared to other nanomaterials, a characteristic that has led to the design of more sensitive and reliable sensors. The exceptional properties of graphene coupled with its potential to be tuned to target specific molecules have made graphene-based sensors one of the most popular and well-researched sensing materials of the past two decades with applications in environmental monitoring, medical diagnostics, and industries. Here, we present a review of developments in the applications of graphene-based sensors in sensing drugs such as cocaine, morphine, methamphetamine, ketamine, tramadol and so forth in the past decade. We compare graphene sensors with other sensors developed from ultrathin two-dimensional materials, such as transition-metal dichalcogenides, hexagonal boron nitrate, and MXenes, to measure drugs directly and indirectly, in various samples.

Green syntheses of graphene and its applications in internet of things (IoT)-a status review

Internet of Things (IoT) is a trending technological field that converts any physical object into a communicable smarter one by converging the physical world with the digital world. This innovative technology connects the device to the internet and provides a platform to collect real-time data, cloud storage, and analyze the collected data to trigger smart actions from a remote location via remote notifications, etc. Because of its wide-ranging applications, this technology can be integrated into almost all the industries. Another trending field with tremendous opportunities is Nanotechnology, which provides many benefits in several areas of life, and helps to improve many technological and industrial sectors. So, integration of IoT and Nanotechnology can bring about the very important field of Internet of Nanothings (IoNT), which can re-shape the communication industry. For that, data (collected from trillions of nanosensors, connected to billions of devices) would be the 'ultimate truth', which could be generated from highly efficient nanosensors, fabricated from various novel nanomaterials, one of which is graphene, the so-called 'wonder material' of the 21st century. Therefore, graphene-assisted IoT/IoNT platforms may revolutionize the communication technologies around the globe. In this article, a status review of the smart applications of graphene in the IoT sector is presented. Firstly, various green synthesis of graphene for sustainable development is elucidated, followed by its applications in various nanosensors, detectors, actuators, memory, and nano-communication devices. Also, the future market prospects are discussed to converge various emerging concepts like machine learning, fog/edge computing, artificial intelligence, big data, and blockchain, with the graphene-assisted IoT field to bring about the concept of 'all-round connectivity in every sphere possible'.

Advances of Drugs Electroanalysis Based on Direct Electrochemical Redox on Electrodes: A Review

The strong development of mankind is inseparable from the proper use of drugs, and the electroanalytical research of drugs occupies an important position in the field of analytical chemistry. This review mainly elaborates the research progress of drugs electroanalysis based on direct electrochemical redox on various electrodes for the recent decade from 2011 to 2021. At first, we summarize some frequently used electrochemical data processing and electrochemical mechanism research derivation methods in the literature. Then, according to the drug therapeutic and application/usage purposes, the research progress of drugs electrochemical analysis is classified and discussed, where we focus on drugs electrochemical reaction mechanism. At the same time, the comparisons of electrochemical sensing performance of the drugs on various electrodes from recent studies are listed, so that readers can more intuitively compare and understand the electroanalytical sensing performance of each modified electrode for each of the drug. Finally, this review discusses the shortcomings and prospects of the drugs electroanalysis based on direct electrochemical redox research.

Selection of DNA aptamers for tramadol through the systematic evolution of ligands by exponential enrichment method for fabrication of a sensitive fluorescent aptasensor based on graphene oxide

Tramadol hydrochloride (TH), as an atypical opioid and a 4-phenyl-piperidine analogue of codeine, is mainly used for treating moderate to severe pains. Due to its extensive application, the consequent need for its analysis in various samples is essential. The current study focuses on the introduction of a rapid fluorescent assay using graphene oxide (GO) and aptamer for determination of tramadol in serum samples. Specific ssDNA aptamers for TH were developed by SELEX (Systematic Evolution of Ligands by EXponential Enrichment) technique using GO as a fluorescence quencher. After 10 rounds, two aptamers (Apt19 and Apt39) were selected from various families. Then, the binding constants of aptamers were measured using fluorometric assay and finally Apt39 (labeled with ATTO 647N) was chosen for development of a fluorescent aptasensor because this aptamer bound to TH with high affinity (K_d = 178.4 nM) and specificity. The current analytical system showed detection limits of 1.04 nM and 2.56 nM in serum sample and phosphate buffer saline (10 mM PBS), respectively.

Designed electrochemical sensor based on metallocene modified conducting polymer composite for effective determination of tramadol in real samples

A novel composite for the electrochemical sensing of tramadol (Tr) was developed by the inclusion of a metallocene mediator between two layers of conducting poly(3,4-ethylenedioxythiophene) (PEDOT) polymer, in the presence of sodium dodecyl sulfate (SDS), i.e., P/mediator/P⋯SDS. Three charge transfer mediators were evaluated: ferrocene carboxylic acid (FC1), ferrocene (FC2), and cobaltocene (CC) for Tr electrocatalytic oxidation. The FC1 charge mediator showed a relatively higher current response that was assisted by the electronic conduction of the polymer film. Moreover, SDS presented a great impact, resulting in the enhancement of the preconcentration and (or) accumulation of Tr ions at the interface, leading to faster electron transfer. In addition, the practical application of the proposed FC1 composite for the determination of Tr in real urine and serum samples was successfully achieved with adequate recovery results. Very low detection limits of 18.6 nM and 16 nM in the linear dynamic ranges of 7–300 µM and 5–280 µM, respectively, were obtained at the proposed sensor. Furthermore, the simultaneous determination of Tr with common interfering species, paracetamol (APAP), morphine (MO), dopamine (DA), ascorbic acid (AA) and uric acid (UA), proved excellent, with good resolution and large potential peaks separation. The excellent characteristics of the proposed composite such as high reproducibility, good sensitivity, selectivity, anti-interference ability, and good stability enhanced its application for determination of other narcotic drugs.

Metal-organic framework precursors derived Ni-doping porous carbon spheres for sensitive electrochemical detection of acetaminophen

The sensitive and selective determination of acetaminophen (AP) in the human body is highly desirable to ensure human health. In this work, nickel-doping nanoporous carbon (Ni/C) was fabricated by directly calcining Ni based metal-organic framework (Ni-MOF). The Ni/C based electrochemical sensor was developed for sensitive and selective determination of AP in human blood serum and urine samples. The prepared Ni/C composite possess plentiful catalytic active sites, ordered mesoporous structure and large specific surface area, which endow the constructed Ni/C sensor with a prominent performance for acetaminophen sensing. Under the optimal conditions, the developed method offered good linearity in the range of 0.20-53.75 μM with a low detection limit (S/N = 3) of 4.04 × 10^-2 μM. The electrocatalytic performance of the sensor towards AP was further measured by differential pulse voltammetry and cyclic voltammetry. The results demonstrated that the Ni/C sensor can be feasibly employed for the determination of AP in human blood serum and urine samples with excellent anti-interference stability and good reproducibility. The research reveals a great promising of the Ni/C electrochemical sensor for clinical applications and paves a way for the construction of high-performance electrochemical sensors for AP determination.

Simultaneous voltammetric determination of epinephrine and acetaminophen using a highly sensitive CoAl-OOH/reduced graphene oxide sensor in pharmaceutical samples and biological fluids

For this study, three novel types of sensors comprised of CoAl-layered double oxyhydroxide (CoAl-LDH), CoAl-LDH/reduced graphene oxide (rGO), and CoAl-OOH/rGO nanosheets were successfully fabricated on glassy carbon electrodes (GCEs) and employed for the electrochemical detection of epinephrine (EP) and acetaminophen (AC). Interestingly, we found that the CoAl-OOH/rGO/GCE was more suitable for the determination of EP and AC in contrast to the CoAl-LDH and CoAl-OOH/rGO sensors. Differential pulse voltammetry results revealed that the CoAl-OOH/rGO/GCE delivered excellent electrocatalytic activity. The sensitivities and detection limits for the simultaneous measurement of EP and AC were 12.2 μA μM^-1 cm^-2, 0.023 μM L^-1, and 4.87 μA μM^-1 cm^-2, 0.058 μM L^-1, respectively. Especially, the as-obtained CoAl-OOH/rGO/GCE was successfully utilized for the detection in pharmaceutical samples and biological fluids with satisfactory results. Owing to its outstanding electrocatalytic activity and superior sensitivity, the CoAl-OOH/rGO/GCE could be beneficial to construct a promising electrochemical sensor for the detection of EP and AC.

Application of magnetic nanomaterials in electroanalytical methods: A review

Magnetic nanomaterials (MNMs) have gained high attention in different fields of studies due to their ferromagnetic/superparamagnetic properties and their low toxicity and high biocompatibility. MNMs contain magnetic elements such as iron and nickel in metallic, bimetallic, metal oxide, and mixed metal oxide. In electroanalytical methods, MNMs have been applied as sorbents for sample preparation before the electrochemical detection (sorbent role), as the electrode modifier (catalytic role), and the integration of the above two roles (as both sorbent and catalytic agent). In this paper, the application of MNMs in electroanalytical methods have been classified based on the main role of the nanomaterial and discussed separately. Furthermore, catalytic activities of MNMs in electroanalytical methods such as redox electrocatalytic, nanozymes catalytic (peroxidase, catalase activity, oxidase activity, superoxide dismutase activity), catalyst gate, and nanocontainer have been discussed.

Tramadol sensing in non-invasive biological fluids using a voltammetric electronic tongue and an electrochemical sensor based on biomimetic recognition

Tramadol (TRA) is a weak opioid analgesic, prescribed to relieve mild to moderately severe pain. However, side effects of TRA overdoses, including vomiting, depression, tachycardia, convulsions, morbidity and mortality are often reported. In this study, an electrochemical sensor based on molecularly imprinted conductive polymer was firstly developed for the quantitative and non-invasive detection of TRA. Secondly, a voltammetric electronic tongue (VE-Tongue) combined with chemometric methods was used for the qualitative analysis. The MIP sensor was constructed by self-assembling a poly-aniline layer coated with silver nanoparticles (PANI-AgNPs) on a screen-printed gold electrode (Au-SPE). Then, 2-amino-thiophenol was polymerised in the presence of TRA. The electronic device exhibits, under optimal conditions, responses proportional to TRA concentrations (0.01-100 µg/mL) with detection and quantification limits of 9.42 µg/mL and 28.55 µg/mL, respectively. Moreover, its selectivity was proven by insignificant interferences of substances (paracetamol and citric acid). Spiked saliva and urine samples were used for the sensor practical application with a significant recovery above 90% and standard deviations below 4.5%. Besides, urine samples' analyses using VE-Tongue and pattern recognition methods show good discrimination, classification, and prediction results with scores above 95%. Correspondingly, both electro-analytical devices could be viable for monitoring drugs in biological matrices.

Chemically modified carbon-based electrodes for the determination of paracetamol in drugs and biological samples

Paracetamol is a non-steroidal, anti-inflammatory drug widely used in pharmaceutical applications for its sturdy, antipyretic and analgesic action. However, an overdose of paracetamol can cause fulminant hepatic necrosis and other toxic effects. Thus, the development of advantageous analytical tools to detect and determine paracetamol is required. Due to simplicity, higher sensitivity and selectivity as well as costefficiency, electrochemical sensors were fully investigated in last decades. This review describes the advancements made in the development of electrochemical sensors for the paracetamol detection and quantification in pharmaceutical and biological samples. The progress made in electrochemical sensors for the selective detection of paracetamol in the last 10 years was examined, with a special focus on highly innovative features introduced by nanotechnology. As the literature is rather extensive, we tried to simplify this work by summarizing and grouping electrochemical sensors according to the by which manner their substrates were chemically modified and the analytical performances obtained.

A facile chemical synthesis of CuxNi(1-x)Fe2O4 nanoparticles as a nonprecious ferrite material for electrocatalytic oxidation of acetaldehyde

In the present work, Cu-doped nickel ferrite (CuxNi(1-x)Fe2O4) nanoparticles (CuNFNPs) were chemically fabricated by adding citric acid as a capping agent followed by combustion and calcination for acetaldehyde oxidation reaction (AOR) in KOH electrolytes. The as-prepared CuNFNPs were studied in terms of Fourier-transform infrared spectroscopy (FT-IR), Transmission electron microscopy (TEM), Field emission scanning electron microscope (FE-SEM), Energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) specific surface area analyses. The morphology of CuNFNPs has sponges-structure containing irregular pores. Additionally, XRD analysis indicated that the prepared CuNFNPs have a cubic-crystals ferrite without the existence of impurities and the crystal size around 20.2 nm. The electrooxidation of acetaldehyde by the presented CuNFNPs was investigated using cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) in -OH media. Furthermore, the effects of -OH and acetaldehyde on the electrocatalytic performance were studied with and without Cu-doping in addition to EIS and CA studies which confirm the high-performance of CuNFNPs as an electrocatalyst for AOR.

A new analytical device incorporating a nitrogen doped lanthanum metal oxide with reduced graphene oxide sheets for paracetamol sensing

The novel N-CeO₂ nanoparticles decorated on reduced graphene oxide (N-CeO₂@rGO) composite has been synthesized by sonochemical method. The characterization of as prepared nanocomposite was intensely performed by UV-Vis, FT-IR, EDX, FE-SEM, HR-TEM, XRD, and TGA analysis. The synthesized nanomaterial was further investigated for its selective and sensitive sensing of paracetamol (PM) based on a N-CeO₂@rGO modified glassy carbon electrode. A distinct and improved reversible redox peak of PM is obtained at N-CeO₂@rGO nanocomposite compared to the electrodes modified with N-CeO₂ and rGO. It displays a very good performance with a wide linear range of 0.05-0.600 μM, a very low detection limit of 0.0098 μM (S/N = 3), a high sensitivity of 268 μA µM^-1 cm^-2 and short response time (<3 s). Also, the fabricated sensor shows a good sensibleness for the detection of PM in various tablet samples.

Preparation and characterization of γ-Fe2O3 nanoparticles and investigation of its adsorption performance for sulfide, sulfite and thiosulfate from aqueous solutions using ultrasonic assisted method: Modeling and optimization

Maghemite nanoparticles, as an adsorbent, was used for the removal of sulfur species including sulfide, sulfite and thiosulfate from waste water samples by ultrasonic-assisted adsorption method. The characterization of the prepared nanoparticles was carried out by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and BET technique. The nanoparticles well dispersed in the water. The adsorbent was easily separated magnetically from the solution after loading with adsorbate. According to central composite design, the best experimental conditions including initial pH, the dosage of adsorbent and sonication time were obtained for sulfide, sulfite and thiosulfate. After optimization of the parameters, the removal of analytes in these conditions lead to the highest analytes removal efficiency (above 98%). The adsorption capacity was evaluated using different adsorption isotherm models. The maximum predicted adsorption capacities for sulfide, sulfite and thiosulfate were obtained as 148.5, 122.5 and 119.6mgg^-1, respectively. Then, desorption process of the adsorbed thiosulfate was also investigated using sodium hydroxide solution as the solvent and the other conditions affect to desorption were optimized.

An ultra-sensitive electrochemical sensor for the detection of acetaminophen in the presence of etilefrine using bimetallic Pd–Ag/reduced graphene oxide nanocomposites

In this study we report a one-step procedure for the fabrication of Pd–Ag bimetallic nanoparticles on the surface of a graphene oxide (rGO) support.

Electrochemical Determination of the Serotonin Reuptake Inhibitor, Dapoxetine, Using Cesium-Gold Nanoparticles

Cesium-gold (Cs-Au) nanoparticles are shown to be analytically advantageous for the electroanalytical sensing of dapoxetine (DPX), a serotonin reuptake inhibitor used for the treatment of premature ejaculation. The Cs-Au nanoparticles are electrically wired and supported upon mass producible, economical screen-printed electrochemical sensing platforms and are characterized electrochemically (cyclic voltammetry and electrochemical impedance spectroscopy) and physiochemically (field emission scanning electron microscopy and energy dispersive X-ray analysis). The face-centered design was applied to optimize the significant experimental factors by using square wave voltammetry. The Cs-Au-based sensor is found to exhibit a large linear range (10-7 to 10-4 M) with a good analytical linearity with the limits of detection and quantification corresponding to 2.50 × 10-10 and 8.33 × 10-8 M, respectively. The developed sensor was successfully applied in the quantification of DPX in the presence of sildenafil, both of which are commonly found within combined dose tablet pharmaceutical formulations. The proposed DPX electrochemical Cs-Au-based sensor has the advantages of being single-shot and disposable and is shown to be successful in determining DPX in pharmaceutical formulations, human urine, and serum samples with acceptable recoveries.