somayeh tajik

In this study, MoSe2/rGO nanocomposite modified screen printed graphite electrode (SPGE) was designed for acyclovir (ACV) determination. The electrochemical investigation and measurement of ACV were performed by applying some voltammetric techniques and chronoamperometry. After modification of SPGE, the enhancement of the voltammetric response and the reduction of overpotential of ACV confirmed the good electrocatalytic ability of MoSe2/rGO/SPGE sensor towards the ACV oxidation. The voltammetric method (differential pulse voltammetry (DPV)) was used to investigate the determination ability of MoSe2/rGO nanocomposite/SPGE towards ACV determination under the optimum parameters and conditions. The MoSe2/rGO/SPGE sensor indicated appreciable sensing ability towards ACV, with an optimal linear response from 0.03-190.0 µM and a limit of detection (LOD) of 0.01 µM. More importantly, the practical applicability of the designed sensor was confirmed in the ACV quantification in ACV tablet and urine samples, showing its potential application for real sample analysis.

Cancer, is a worldwide epidemic, is characterized by the abnormal growth of cells and their ability to spread to various organs and tissues within the body. Doxorubicin (DOX) is an effective chemotherapy drug that not only inhibits the growth of cancer cells, but also assists in the immune-mediated elimination of tumor cells. Hence, it is critical to carefully regulate the DOX dosage for cancer patients undergoing drug-based cancer treatment. Nowadays, electrochemical sensors have emerged as reliable analytical instruments for detecting a broad spectrum of target molecules. This is because of their simplicity, affordability, and ability to seamlessly integrate with multiplexed and point-of-care strategies. By modifying the surface of electrodes with diverse materials, it is possible to enhance the sensitivity and lower the detection limits (LOD) of electrochemical sensors. This report provides a concise summary of selected studies that focus on the use of electrochemical sensors based on carbon nanomaterials and polymers for the DOX analysis, and offers insights on the technical advancements and potential future applications in this particular domain.

In the present research, an effective adsorbent as titled multiwall carbon nanotube/ZnCo- Zeolite imidazole frameworks (MWC/ZIF) was prepared and used for removal of Pb(II) ion from effluent samples. After separating the adsorbent from the solution, the amount of Pb(II) ion in the solution was measured using an atomic absorption device. Based on this, various experimental parameters effective on lead removal including pH, ionic strength, time, temperature, and Pb(II) ion concentration were investigated. Various kinetic models were also studied to assess adsorption kinetics of Pb(II) ions onto surface of MWC/ZIF nanocomposite. With reference to the obtained findings, the produced nanocomposite was assumed as an effective adsorption approach for removal of Pb(II) ions from effluent samples.

In the present study, a fast, sensitive, and simple electrochemical sensor based on screen-printed graphite electrode (SPGE) modified with Ce-1,3,5-benzenetricarboxylic acid (Ce-BTC) metal-organic framework (MOF) has been prepared for determination of metronidazole (MNZ). The electrochemical studies and measurements were done using cyclic voltammetry (CV), linear sweep voltammetry (LSV), differential pulse voltammetry (DPV), and chronoamperometry techniques. Comparison study of electrochemical performance of unmodified SPGE and Ce-BTC MOF/SPGE toward the reduction of MNZ was evaluated by using CV. The CV studies show that modification of SPGE surface with Ce-BTC MOF enhances the reduction peak current but the peak potential of MNZ has shifted to the lower potential. Using the effects of Ce-BTC MOF, the developed modified SPGE showed good electrochemical sensing performance for detecting MNZ in phosphate buffer solution (PBS) (pH = 7.0) with wide linear range (0.05-400.0 µM), high sensitivity (-0.0304 µA/µM), and low limit of detection (LOD) (0.02 µM). Finally, for the MNZ analysis in real samples, the Ce-BTC MOF/SPGE sensor exhibited good MNZ determination performance with acceptable recoveries of 96.7%-103.6% and low relative standard deviation (RSD) values of 1.8%-3.5%.

In this work, an easy method was employed to successfully develop La3+-doped ZnO nanoflowers and Guar-Gum (GG) modified screen printed electrode (La3+/ZnO/GG/SPE), and La3+/ZnO/GG/SPE was applied for the electrochemical detection of Ascorbic Acid (AA). The electrochemical methods, such as Cyclic Voltammetry (CV), chronoamperometry (CHA), and Differential Pulse Voltammetry (DPV) were used to evaluate the electrochemical performances toward ascorbic acid on the La3+/ZnO/GG/SPE. Good linear-ship was observed for ascorbic acid in the ranges of 1.0–700.0 μM, with the detection limits of 0.03 μM. Moreover, this sensor proved favorable to simultaneously determine ascorbic acid and acetaminophen. Finally, the modified electrode has fairly good performance during the employment of real sample analysis to determine the content of ascorbic acid. These results indicate that the La3+-doped ZnO nanoflowers are supposed to be a promising material in the electrochemical determination of ascorbic acid and acetaminophen in real samples.

Since monitoring of drug metabolism and drug quality control plays an important role in human health, the development of easy, correct, and sensitive methods for the detection of active ingredients is important. Different methods have been developed for measuring dopamine in biological samples. In this study, a Screen Printed Electrode (SPE) modified with manganese dioxide nanorods (MnO2) was used as a simple and high sensitive sensor for detecting and measuring dopamine in real samples. The electrochemical behavior of dopamine at SPE was studied using cyclic voltammetry, differential pulse voltammetry, and chronoamperometry. In addition, by using the differential pulse voltammetry method, the calibration curve was obtained at a concentration range of 1.0-0.900 μm with a detection limit of 0.1 μm.

The present study reports synthesis of MOWS2 nanocomposite followed by its characterization using energy dispersive X-ray spectroscopy (EDS), X-Ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Chronoamperometry (CHA), differential pulse voltammetry (DPV), and cyclic voltammetry (CV) have been used to examine electro-chemical behaviors of sulfite on MOWS2 nanocomposite modified SPE. Electro-chemical specification indicated very good electro-catalytic activities and surface area impact of MOWS2 nanocomposite. Oxidation signals of sulfite on MOWS2/SPE has been considerably increased in comparison to the bare SPE. Within optimum conditions, quantification of sulfite might range between 0.08 to 700.0 µM with a small determination limit of 0.02 µM based on S/N=3.The impact of scan rates has been explored. Finally, the MOWS2/SPE has been employed for detection of sulfite in real specimens. In general, an easy experimental method for manufacturing MOWS2 nanocomposite has been suggested that takes advantage of selectivity, reproducibility, and sensitivity toward electro-active specimens, as well as biological matrices.

Hydrazine has been identified as a carcinogenic mutagenic, hepatotoxic, and neurotoxin material. A metal-organic framework with tetragonal symmetry, DMOF-1 (Zn2(bdc)2dabco) was synthesized by a versatile and facile technique, followed by its efficient development and validation as hydrazine electrochemical sensor. Differential pulse voltammetry (DPV), linear sweep voltammetry (LSV), and cyclic voltammetry (CV) techniques were used as diagnostic techniques. In this study, scanning electron microscopy (SEM) and x-ray diffraction (XRD) were used to characterize the MOF. In the electro-oxidation of hydrazine, there was a highly catalytic activity shown by the modified electrode. In addition, there was a greater signal response, compared to the unmodified electrode, which was primarily because DMOF-1 offered the establishment of large active surface area. Also, the detection limit for hydrazine, linear range, and sensor sensitivity were reported to be 0.02 µM, 0.09-400.0 µM, and 0.0863 µA/µM-1, respectively. Ultimately, the amplified sensor was able to properly analyze hydrazine in different samples of water.

The use MOF-508a as sensing component for the precise discerning of bisphenol A via the electrochemical technique and its synthesis by a simple method were reported in the present study. Scanning electron microscopy (SEM) and x-ray diffraction (XRD) were applied to describe the MOF-508a’s composition and structure. In addition, MOF-508a was exploited so that the glassy carbon electrode could be altered for the bisphenol A’s electrochemical oxidation. The results were indicative of illustration of palpable oxidation peak with lowering over-potential by the designed MOF-508a /GCE. In addition, there was a greater signal response, compared to the unmodified electrode, which was primarily because MOF-508a offered the establishment of large active surface area. As such, this process led to a considerable improvement in the electrochemical surface area. Moreover, adding the elevating bisphenol A concentration resulted in a severe elevation in the anodic peak, presented by the measurements of differential pulse voltammetry (DPV). Furthermore, excellent sensitivity (0.0564 µA.µM-1) with low limit of detection (0.03 µM), a wide linear range (0.1–700.0µM), and high selectivity were shown by the analytical performance of the modified electrode.

Risk of diabetes mellitus type 2 (T2DM) is variable between individuals due to different metabolic phenotypes. In present network meta-analysis, we aimed to evaluate the risk of T2DM related with current definitions of metabolic health in different body mass index (BMI) categories.

Relevant articles were collected by systematically searching PubMed and Scopus databases up to 20 March 2018 and for analyses we used a random-effects model. Nineteen prospective cohort studies were included in the analyses and metabolically healthy normal weight (MHNW) was considered as the reference group in direct comparison for calculating indirect comparisons in difference type of BMI categories.

Total of 199403 participants and 10388 cases from 19 cohort studies, were included in our network meta-analysis. Metabolically unhealthy obesity (MUHO) group poses highest risk for T2DM development with 10 times higher risk when is compared with MHNW (10.46 95% CI; 8.30, 13.18) and after that Metabolically unhealthy overweight (MUOW) individuals were at highest risk of T2DM with 7 times higher risk comparing with MHNW (7.25, 95% CI; 5.49, 9.57). Metabolically healthy overweight and obese (MHOW/MHO) individuals have (1.77, 95% CI; 1.33, 2.35) and (3.00, 95% CI; 2.33, 3.85) risk ratio for T2DM development in comparison with MHNW respectively.

In conclusion we found that being classified as overweight and obese increased the risk of T2DM in comparison with normal weight. In addition, metabolically unhealthy (MUH) individuals are at higher risk of T2DM in all categories of BMI compared with metabolically healthy individuals.

In the present work, a new sensor for morphine (MO) measurement, based on modification of screen-printed carbon electrode (SPE) by using magnetic core shell manganese ferrite nanoparticles was reported. The electrochemical behaviour of MO was investigated in phosphate buffer solution (pH 7.0) by voltammetry. The electrochemical response of the modified electrode toward morphine was studied by means of cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronoamperometry (CHA). The modified electrode displayed a decrease in the overpotential (ca. 80 mV) and an obvious increase in the peak current was observed compared to the non-modified SPE. The results indicated that modified screen-printed electrode enhanced electrocatalytic activity towards the oxidation of MO. Under the optimized conditions the calibration curve for MO was linear from 0.1 – 600.0 μM and the detection limit based on 3Sb/m was 0.02 µM. The application of the proposed method in analysis of real sample was also evaluated and satisfactory results were obtained.

In the present study, the cysteamine electrochemical features were explored by La2O3/Co3O4 nanocomposite-modified screen printed electrode (La2O3/Co3O4/SPE) using voltammetry, chronoamperometry, and differential pulse voltammetry (DPV) techniques. The synthesized La2O3/Co3O4 nanocomposite qualities were considered by SEM, FT-IR, and XRD analyses. Exploiting the modified SPE electrode with La2O3/Co3O4 nanocomposite, the cysteamine electrooxidation kinetics was significantly enhanced by reducing the anodic over-potential. The constructed La2O3/Co3O4/SPE revealed voltammetric reactions of high sensitivity for cysteamine, resulting in a highly appropriate means of trace levels cysteamine measurement. The electrooxidation peak currents for cysteamine were found to change linearly in relation to its concentrations (1.0–700.0 μM) in detection limit of 0.3 μM. La2O3/Co3O4/SPE was utilized for the cysteamine quantification in real specimens.

A glassy carbon electrode modified with graphene oxide (GO/GCE) is proposed as a novel electrochemical platform for detection of chlorpromazine. The electrochemical activity of GO/GCE towards chlorpromazine was investigated using cyclic voltammetry (CV) experiments in 0.1 M phosphate buffer solution (PBS). The overpotential for the oxidation of chlorpromazine decreased significantly and its oxidation peak currents increased dramatically at GO/GCE. The potential utility of the sensor was demonstrated by applying it to the analytical determination of chlorpromazine concentration using differential pulse voltammetry (DPV). These results are beneficial for real sample analysis. The sensor worked linearly in the range of 0.05 to 200.0 μM and had a detection limit of 42.0 nM using DPV. The fabricated sensor was successfully applied to the detection of chlorpromazine in real samples. The experiments illustrate that graphene oxide is a worthy electrode material which offers a large surface-to-volume ratio and improves the sensitivity. Here, a new sensor is introduced that is simple, rapid, sensitive and cost-effective for quantitation of chlorpromazine.

In this study, we combined the advantages of good conductivity, small size, and large surface area and the catalytic property of La3+/Co3O4 nanoflowers to fabricate an electrochemical sensor sensitive to determination of vitamin B6 in real samples. La3+/Co3O4 nanoflowers were synthesized by a co-precipitation method which is a convenient, environment-friendly, inexpensive process. The synthesized nanoflowers were characterized by SEM. A simple and sensitive sensor based on graphite screen printed electrode (GSPE) modified by La3+/Co3O4 nanoflowers was developed for the electrochemical determination of vitamin B6. The electrochemical behavior of vitamin B6 was studied in 0.1 M phosphate buffer solution (PBS) using cyclic voltammetry (CV), chronoamperometry (CHA) and differential pulse voltammetry (DPV). The modified electrode (La3+/Co3O4NFs/GSPE) showed excellent electrocatalytic activity and remarkable sensitivity towards the oxidation of vitamin B6. The fabricated sensor displayed good operating characteristics including low detection limit, and a wide linear dynamic range for the detection of vitamin B6. Using La3+/Co3O4NFs/GSPE as the working electrode, a linear dynamic range between 1.0 to 600.0 μM and a limit of detection of 0.4 µM were obtained. Finally, reliability and accuracy of the proposed sensor were studied in real samples.

Dopamine (DA) is one of the most important catecholamine neurotransmitters in the human central nervous system in the brain and plays a key role in the functioning of the renal, hormonal, and cardiovascular systems. Abnormal levels of dopamine are related to neurological disorders, such as schizophrenia and Parkinson’s disease and the control and fluctuations of the amount of dopamine are extremely important in monitoring with analytical systems in the human brain. This review covers the different electrochemical sensors for the determination of dopamine as neurotransmitter and points out the advantages and disadvantages of them. The interaction between the functional groups of the sensor’s material and the analyte molecule is discussed, as it is essential for the analytical characteristics obtained. The analytical performances of the voltammetric or amperometric chemical and biochemical sensors (linear range of analytical response, sensitivity etc) are highlightened. The numerous applications of DA electrochemical sensors in fields like pharmaceutical or clinical analysis, where DA represents a key analyte, are also presented.

This paper gives a comprehensive review about the most recent progress in graphene and graphene oxide based electrochemical sensors and biosensors. Graphene, emerging as a true 2-dimensional material, has received increasing attention due to its unique physicochemical properties (high surface area, excellent conductivity, high mechanical strength, and ease of functionalization and mass production). The application of graphene and graphene oxide in the modification processes leads to improved sensitivity, electrocatalytic behavior, and reduced fouling. The development of graphene and graphene oxide based sensors in biosensing and detection of chemicals have been resulted in great achievements towards more sensitive health care instruments and preventing the environmental problems. To facilitate further research and development, the technical challenges are discussed, and several future research directions are also suggested in this paper.

A high sensitive electrochemical nanostructure sensor based on graphene oxide/Fe3O4@SiO2 nanocomposite modified graphite screen printed electrode (GO/Fe3O4@SiO2/SPE) has been developed for trace analysis of acetaminophen. The electrochemical study of the modified electrode, as well as its efficiency for simultaneous voltammetric oxidation of acetaminophen and tryptophan is described. Compared with bare SPE the GO/Fe3O4@SiO2/SPE exhibited excellent electrocatalytic activity toward the oxidation of acetaminophen. The plot of catalytic current versus acetaminophen concentration showed a linear segment in the concentration range 0.5 to 100.0 µM. The detection limit of 0.1 µM was obtained using calibration plot. Also the anodic peaks of acetaminophen and tryptophan in their mixture can be well separated. The GO/Fe3O4@SiO2/SPE has been successfully applied and validated by analyzing acetaminophen and tryptophan in urine and pharmaceutical samples.

NiFe2O4 nanoparticles were successfully applied at a screen printed electrode (NiFe2O4/SPE). At first, NiFe2O4 nanoparticles were deposited on the SPE. This new modified electrode system was characterized by cyclic voltammetry (CV), chronoamperometry (CHA) and differential pulse voltammetry (DPV). NiFe2O4/SPE was used for simultaneous determination of serotonin and norepinephrine. It was observed that an electrode with electrochemical deposited of NiFe2O4 nanoparticles has higher electrocatalytic activity for the oxidation of serotonin. Differential pulse voltammetry exhibited a linear dynamic range over the concentration range of 0.1-300.0 μM and a detection limit (3σ) of 0.07 μM for serotonin in the optimum conditions. Finally, DPV was used for simultaneous determination of serotonin and norepinephrine and their detection real samples.

In this work, a sensitive Sudan I electrochemical sensor was assembled using NiFe2O4 nanoparticles modified screen printed electrode. Due to the synergetic effect of NiFe2O4 nanoparticles displayed high electrochemical activity with well-defined voltammetric peaks of Sudan I oxidation and lower overpotential compared with unmodified electrode. According to the results of differential pulse voltammetry (DPV), under optimized conditions, a good linear response was observed for the concentration of Sudan I in the range of 0.1–100.0 μM with a detection limit of 0.05 μM. The developed electrochemical sensor was successfully applied to determine Sudan I in water samples. This study indicated that NiFe2O4 nanoparticles based electrochemical sensor can be a promising and reliable tool for rapid analysis of Sudan I.

Bisphenol A (BPA) is an effective endocrine-disrupting compound (EDC) that causes adverse effects on human health and environment. This study reported a novel bisphenol A sensor via MnO2 nanorods modified screen printed electrode. The prepared MnO2/SPE presented fast response, high sensitivity and low background current. Differential pulse voltammetry (DPV) was used as an analytical method for the quantitative determination of bisphenol A, and the fabricated electrochemical sensor exhibits a linear response to bisphenol A in the range of 1.0–300.0 μM with the limit of detection (LOD) of 0.5 μM at a signal-to-noise ratio of 3. The prepared MnO2/SPE has been successfully used for detecting bisphenol A in water samples.

Levodopa, one of the prescribed medications in Parkinson disease, is electrochemically determined here. A Cu/TiO2 nanocomposite/room temperature ionic liquid/2-(ferrocenylethynyl)fluoren-9-one modified carbon paste electrode (Cu/TiO2-IL- 2FF/CPE) was used for the electrochemical determination of levodopa. The electro oxidation mechanism of levodopa at Cu/TiO2-IL-2FF/CPE was also studied. The obtained data showed that the electro-oxidation of levodopa at the Cu/TiO2-IL-2FF/CPE is greatly facilitated, which is attributed to high electrical conductivity of Cu/TiO2 nanocomposite, room temperature ionic liquid and 2-(ferrocenylethynyl)fluoren-9-one. The Cu/TiO2-IL-2FF/CPE showed a good electron mediating behavior followed by well separated oxidation signals of levodopa and tyrosine. Differential pulse voltammetric peak current showed a linear relationship corresponds to the concentrations of levodopa in a linear range of 0.03 to 700.0 μM with detection limit of 12.0 nM. The Cu/TiO2-IL-2FF/CPE shows excellent ability to determination of levodopa and tyrosine in real samples.

Obesity is a worrying problem in the present age and is the cause of many chronic non-communicable diseases. Several nutritional and non-nutritional factors are involved in the emergence of this health crisis. One of the important nutritional factors is the quality of nutrition. In this study, the relationship of the Alternative Healthy Eating Index (AHEI-2010) in relation to obesity, vitamin D3, and CRP, was investigated in the elderly.
This descriptive-analytic (cross-sectional) study, was performed on 190 older adults referred to health centers of Tehran University of Medical Sciences using cluster sampling. Food intake was measured by Food Frequency Questionnaire. The level of vitamin D and hs-CRP were calculated in fasting blood, and variables of weight, height, and waist circumference, were measured .In the final analysis with logistic regression, confounding factors, were adjusted and p The mean age of the subjects, was 67.31 and the mean BMI was estimated to be 29. 89. The distribution of the individuals in terms of weight, body mass index, and waist circumference, was not significant based on AHEI-2010. The odds ratio of abdominal obesity based on AHEI-2010, was estimated to be OR=0.85 after adjusting for confounders, which was not statistically significant, but this distribution was not significant for the odds ratio of general obesity (p=1.20).
The findings of this study revealed that by increasing the score of AHEI-2010, the odds ratio of abdominal obesity decreases, but there is not significant relationship between the AHEI-2010 and general obesity, vitamin D3, and hs-CRP.

A Cu(II) nanocomplex, [CuCl2(salophen)].H2O[salophen=ophenylenediaminebis(salicylidenaminato)], was synthesized. The electrochemical properties of the as-prepared Cu(II) nanocomplex modified graphite screen printed electrode (Cu/SPE) were investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Moreover, as a nanosensor for the determination of norepinephrine the Cu/SPE exhibited excellent electrocatalytic activity for the oxidation of norepinephrine with a faster electrontransfer rate. The DPV technique was used for the trace determination of norepinephrine. The dependence of current vs. concentration was linear from 0.3 to 300.0 μM with a regression coefficient of 0.9992, and the detection limit of norepinephrine was 0.09 μM. Finally, the method was applied to the selective and precise analysis of norepinephrine in norepinephrine injection.

Electrochemical behaviors of carbidopa at the surface of the graphite screen printed electrode (SPE) modified with Cu(II) nanocomplex, [CuCl2(salophen)]. H2O (salophen=o-phenylenediaminebis(salicylidenaminato)) were studied. The oxidation peak potential of the carbidopa at a surface of Cu/SPE appeared at 360 mV that was about 100 mV lower than the oxidation peak potential at the surface of the traditional SPE under similar condition. On other hand, the oxidation peak current was increased for about two times at the surface of Cu/SPE compared to SPE. The linear response range and detection limit were found to be 0.5-700 μM and 0.1 μM, respectively. The proposed sensor was successfully applied for the determination of carbidopa in real samples.

A novel modified graphite screen printed electrode (SPE) is prepared as an electrochemical sensor for determination of levodopa. The experimental results suggest that a screen printed electrode (SPE) modified with Cu(II) nanocomplex, [CuCl2(salophen)].H2O (salophen= o-phenylenediaminebis(salicylidenaminato)), accelerates the electron transfer reactions of levodopa. The fabricated sensor revealed some advantages such as convenient preparation, good stability and high sensitivity. The DPV data in 0.1 M phosphate buffer solution (PBS) (pH 7.0) allowed a method to be developed for the determination of levodopa concentrations in the ranges 5.0–900.0 μM, with the detection limits of 0.9 μM. The proposed method was successfully applied to determinations of levodopa in urine samples.