Analytical and Bioanalytical Chemistry Research
Volume:9 Issue: 1, Winter 2022

In recent years, biosensors are used in various applications ranging from biomedical and pharmaceutical to food and chemical products. As an example, biosensors can be used for glucose assessment in blood and regulation of insulin usage in diabetic patients. In this regard, it is anticipated that many diseases could be diagnosed in the near future at an early stage regarding further progress in nanotechnology. The advancement in nanotechnology meets the technological requirements for the increased demand for sensors in biomedical applications. Enzymes play a significant role among various biologic elements exerted in the design of biosensors. Glucose oxidase is an enzyme and biocatalysts that accelerate the process of turning glucose to oxygenated water. Recent surveys have reported the novel qualitative and quantitative approaches used to enhance the sensitivity, detection limit, and biocompatibility of biosensors. Furthermore, they have confirmed the enhanced performance of glucose-based biosensors in both response and detection limits in their implementation. This review aims to summarize recent progress in sensitivity, selectivity, response time, and stability of the enzymatic biosensor based on the versatile fabrication of glucose by semi-permeable membranes.

Polyamidoamine dendrimers-MoS2 nanocomposites for photocatalytic degradation of chlorpyrifos and glyphosate pesticidesPolyamidoamine dendrimer functionalized with MoS2 nanoparticles was synthesized and fully characterized using field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffractometry, Brunauer-Emmett-Teller, and thermal gravimetric analysis. The synthesized nanocomposite showed excellent photocatalytic activities for the degradation of two commonly used pesticides (chlorpyrifos and glyphosate). According to the optimization study, the pH value of 10 and the minimum reaction time of 110 minutes is required for optimal degradation of pesticides. Based on the kinetics study on the photocatalytic reaction, it was inferred that more than 95% of the pesticides were degraded into non-harmful products in less than two hours. By comparing the obtained data in this study with previous reports for photocatalytic degradation of chlorpyrifos and glyphosate, it was concluded that the present nanocomposite was able to degrade pesticides faster and more efficient.Keywords: Chlorpyrifos, Glyphosate, Polyamidoamine dendrimer, Photocatalyst, Pesticide

An in-situ solvent formation microextraction technique as another attractive mode of homogeneous liquid-liquid microextraction, was developed successfully for the sensitive extraction of cadmium ion. In this technique use green extracting solvent such as ionic liquids that are environment lover. So, because using ionic liquids, this technique is much safer than other extraction methods which use toxic common organic solvents. Functionalized ionic liquid of 3-(2-(bis(2-(tert-butoxy)-2-oxoethyl)amino)ethyl)-1-methylimidazolium bromide was used as extractant and organic phase which has double role including complexing agent and extractant, so to extraction of cadmium ion, not need to any complexing agent. To optimization of extraction conditions, several analytical parameters affected on microextraction efficiency including sample pH, functionalized ionic liquid dosage, counter-ion amount and centrifugation conditions were studied. To show abilities of the method, the figures of merits including limit of detection and quantification, relative standard deviation, linear dynamic range and enrichment factor were calculated and included 0.23 µg/L, 0.76 µg/L, 1.8%, 10-1500 µg/L and 75, respectively. It was found from results that the method was applied successfully for the determination of Cd (II) ion in several real, and saline samples. Because of use environmental solvents such as ionic liquids, and very small dosage of its, it can be said the method has low toxicity and classified as a green extraction/preconcentration technique. One the other hand, the presented method opens a new window in the analytical applications due to its costless, ease in experimental setup and use of non toxic solvents as an extractant.

A mesoporous silica SBA-15/iron oxide (Fe3O4-SBA-15) nanocomposite was fabricated and employed as a magnetic solid-phase extraction (MSPE) sorbent to determine three types of organophosphorus pesticides (OPPs) in fruit samples. The fabricated nanocomposite was analysed using high-performance liquid chromatography with an ultraviolet detector (HPLC-UV). Meanwhile, the optimisation of extraction efficiency on three OPPs analyses used three different parameters, viz. desorption conditions, extraction time, and sorbent amount. The experimental results showed that the Fe3O4-SBA-15 nanocomposite achieved high analyte recoveries ranging from 89 to 118% with a relative deviation of less than 8.0%. By combining the optimised MSPE conditions with HPLC-UV, a suitable method for determining three OPPs was developed. This study revealed that the proposed method exhibits good coefficients of determination varying from 0.9942 to 0.9980, with low limit detection (LODs) ranging from 0.03 - 0.08 mgL-1 and low limit quantifications (LOQs) of 0.10 - 0.24 mgL-1. Based on these findings, the fabricated Fe3O4-SBA-15 nanocomposite is a suitable sorbent with excellent adsorption capacity for the selected OPPs from fruit matrices.

Due to vital essence of medicine dosage monitoring within therapeutic range, a simple, rapid, high performance, sensitive and environmentally friendly electrochemical sensor was designed and used to diagnosis low concentrations of famotidine, a histamine-2 blocker, at pharmaceutical products and biological fluids. In this work, a simple, fast response and efficient voltammetic sensor was designed by using the functionalized dendrite-like gold nanostructures with 3-mercapto-propanioc acid (3-MPA/Au-DNSs). Electrochemical studies confirmed well the efficiency of the surface modified glassy carbon electrode (GCE) with 3-MPA/Au-DNSs on amplification of response signal in presence of famotidine in an applicable linear concentration range of 3.0 × 10−7–1.0 × 10−5 M. The limit of detection was evaluated to be 3.33 × 10−8 M (for S/N=3) under the optimum conditions. The modified GCE with 3-MPA/Au-DNSs was successfully applied in determination of famotidine in real samples such as human serum and pharmaceuticals with recoveries of 104.8 % and 100.90%, respectively.

This study represents the application of MCR-ALS for the separation of the different sources of variation in a series of the linear sweep voltammograms obtained from the oxidation of the Mefenamic acid as a model analyte on a poly L-proline and MWCNT-modified GCE. Two types of faradaic currents including adsorption and diffusion were separated successfully and the effects of the accumulation time and the concentration of Mefenamic acid were investigated on the variation of the charging current. The results showed that the contribution of the charging current on the measured signal decreases upon increasing the adsorption as a result of the blockage of the electrode active sites with the adsorbed species which is in agreement with the previous studies. The proposed methodology was employed for voltammetric determination of Mefenamic acid with enhanced figures of merit in real serum samples by removing the contribution of the charging current from the measured signal. The obtained results indicate the lower detection limit as 90 nM, wider linear range and higher sensitivity compared to the unprocessed and background-subtracted data.

Insulin detemir (ID) is a long-acting form of insulin that is characterized by the covalent attachment of a lipophilic tail of myristate, and commercially available as Levemir®. No satisfactory simple isocratic stability-indicating HPLC method has been reported for its quality control. A novel simple and isocratic reversed-phase HPLC method was developed and validated for the simultaneous determination of ID along with its dosage form additives in the available commercial preparations. The method employed C4 column (5μm, 250 × 4.6 mm), a mobile phase consisting of 50 mM phosphate buffer pH 2.7, acetonitrile, triethylamine (62:37:1) and 0.02 g/ml sodium sulfate, that was delivered isocraticaly at a flow rate of 1.5 ml/min, and detection performed at 214nm. The method was properly validated and was shown linear over the range 80–120% of the assay concentration for ID, phenol, and m-cresol. The method was also selective, specific, precise, and accurate. Furthermore, the validated method was applied to separate the major degradation products in those preparations. Forced degradation studies in different pH values, which are the first to be reported for ID, showed that the degradation products were baseline separated from ID itself and/or other formulation additives. Thus, the method has been demonstrated to be a stability-indicating assay.

Melia azedarach fruit extract is used to synthesize iron-polyphenol nanohydrogel and its capability as a flocculant in coagulation and removal of Disperse Yellow 211 dye from the aqueous solution is examined. The structure of iron-polyphenol nanohydrogel is studied by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, X-ray diffraction, Brunauer-Emmett-Teller analysis, and zeta potential. The field emission scanning electron microscopy analysis indicates that in situ-cross-linking of polyphenols of Melia azedarach extract by ferric ions resulted in the formation of nanohydrogel containing particles in the range of 23-35 nm. Experiments confirmed that the prepared iron-polyphenol nanohydrogel has the excellent ability as the flocculant for coagulation and removal of the Disperse Yellow 211 dye in the pH range of 4.0-8.0, at room temperature. The required time for obtaining equilibrium at different concentrations of dye is ~ 50 minutes, and in this period, 200 mg L-1 of dye solution is 92% decolorized. The best-fitted model for experimental data is found to be the second-order kinetics and Langmuir thermodynamic indicating the sorption occurs in a monolayer and is governed by chemisorption. The maximum capacity of the sorbent is 1111.1 mg g-1.

A novel composite was fabricated utilizing gold nanoparticle-modified (AuNPs) reduced graphene oxide (rGO) composite and acetoneextracted propolis (AEP) for electrochemical sensors on screen-printed electrodes (AuNPs/rGO/AEP/SPE) using electrochemical approaches for tartrazine (Tz) detection. Electrochemical experiments and scanning electron microscopy (SEM) were applied for electrode characterization. The diagrams of provided cyclic voltammetry (CV) indicated that the highest Tz oxidation catalytic activity was provided for AuNPs/rGO/AEP/SPE followed by rGO/AEP/SPE, GO/AEP/SPE, and SPE. Utilizing differential pulse voltammetry (DPV) techniques in the range of 0.004 to 2 µM with a detection limit of 3 nM, the range for Linear Tz calibration curves were provided at AuNPs/rGO/AEP/SPE. The findings of this study showed that AuNPs/rGO/AEP/SPE could be applied for Tz detection with high stability, low detection limit, and high sensitivity, which appear to be helpful in the manufacture of portable sensors for use in the food industry.

Green luminescent water-soluble carbon dots (CDs); were synthesized by the simple one-step hydrothermal method of: beef, shrimp, beef liver and, oyster, without using a surface passivating and oxidizing agents or inorganic salts. The application of high fluorescent beef CDs; without surface modification was described as a green, simple, and inexpensive method for sensitive and selective determination of ketotifen fumarate (KTF) based on fluorescent quenching. The beef CDs exhibit exceptional advantages, including: significant fluorescent quantum yield (13.75), and, admissible chemical stability. The quantum yields of CDs from beef, oyster, beef liver, and shrimp were calculated as: 13.75, 17.29, 20.59, and 17.45, respectively. Among the prepared CDs, only the fluorescence of CDs prepared from beef was significantly reduced by KTF, indicating the high selectivity of beef CDs toward KTF. The linear range of determination of KTF by this nanosensor was 7.00  10-7 -5.00  10-6 M with a detection limit of 0.30 μM. The proposed method was then applied to the highly sensitive and selective determination of KTF in human serum and urine samples with acceptable results.