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1.
BMC Endocr Disord ; 22(1): 45, 2022 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-35189898

RESUMO

BACKGROUND: Although various dietary patterns have been indicated to be associated with the resting metabolic rate [RMR], limited data are available in this field. This study was therefore focused on the association between dietary patterns and resting metabolic rate among participants with overweight and obesity. METHODS: This cross-sectional study was conducted on 304 women with overweight or obesity (BMI ≥ 25 kg/m2), aged 18-50. Anthropometric assessments, physical activity and biochemical measurements were assessed. RMR was also measured by means of indirect calorimetry. Dietary intake of participants was evaluated by 147-item semi-quantitative food frequency questionnaire [FFQ]. RESULTS: There was a significant association between higher adherence to the healthy dietary pattern [HDP] and RMR (P = 0.05), intakes of protein (P = 0.003), minerals (P = 0.001) as well as fat free mass [FFM] (P = 0.002), bone mineral content (P = 0.001), skeletal muscle mass (P = 0.001), soft lean mass (P = 0.002) and visceral fat area (P = 0.05). Also, there was a considerable association between higher adherence to the unhealthy dietary pattern [UHDP] and fasting blood sugar [FBS] (P = 0.05). Using multinomial logistic regression has been shown that the medium adherence to the HDP was marginally significant with decreased resting metabolic rate [Dec. RMR] group in crude model (OR: 0.54; 95% CI: 0.28-1.05, P = 0.07). After controlling for various confounders such as age, FFM, physical activity, and energy intake, the association between Dec. RMR group and the lowest quartile of the HDP (OR: 0.36; 95% CI: 0.14-0.91, P = 0.03) became significant as well as the association between Dec. RMR group and medium adherence to the HDP (OR: 0.42; 95% CI: 0.18-0.97, P = 0.04). The medium adherence to the UHDP in crude model was also significant with increased resting metabolic rate [Inc. RMR] group (OR: 2.59; 95% CI: 1.01-6.65, P = 0.04). CONCLUSIONS: Our study showed that there are significant associations between dietary patterns and RMR status.


Assuntos
Metabolismo Basal , Ingestão de Alimentos , Obesidade/metabolismo , Sobrepeso/metabolismo , Adolescente , Adulto , Antropometria , Biomarcadores/sangue , Calorimetria Indireta , Estudos Transversais , Dieta Saudável , Feminino , Humanos , Pessoa de Meia-Idade
2.
Environ Res ; 214(Pt 1): 113725, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35732202

RESUMO

Azo dyes are the most used type of dye in the textile industry. Some of these dyes have the potential to be extremely toxic to both human health and the environment. The purpose of this study was to develope an electrochemical sensor for detection of amaranth. The electrochemical sensor based on the modification of a screen-printed electrode via polypyrrole nanotubes (PPy NTs/SPE) for detection of amaranth was developed. The preparation of PPy NTs was performed through the pyrrole monomer oxidation with iron (III) chloride in exposure to methyl orange as structure-guiding agent. Findings exhibited an excellent electrocatalytic activity of as-fabricated sensor for amaranth detection. Our sensor under the optimized circumstances also had a broad linear dynamic range (between 0.03 µM and 290.0 µM) and a narrow limit of detection (0.01 µM) towards the amaranth detection. Moreover, the proposed sensor could practically and successfully determine the amaranth content present in the real food specimens, with acceptable recovery rates.


Assuntos
Nanotubos de Carbono , Polímeros , Eletrodos , Humanos , Pirróis
3.
Sensors (Basel) ; 22(6)2022 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-35336408

RESUMO

Many studies have addressed electrochemical biosensors because of their simple synthesis process, adjustability, simplification, manipulation of materials' compositions and features, and wide ranges of detection of different kinds of biomedical analytes. Performant electrochemical biosensors can be achieved by selecting materials that enable faster electron transfer, larger surface areas, very good electrocatalytic activities, and numerous sites for bioconjugation. Several studies have been conducted on the metal-organic frameworks (MOFs) as electrode modifiers for electrochemical biosensing applications because of their respective acceptable properties and effectiveness. Nonetheless, researchers face challenges in designing and preparing MOFs that exhibit higher stability, sensitivity, and selectivity to detect biomedical analytes. The present review explains the synthesis and description of MOFs, and their relative uses as biosensors in the healthcare sector by dealing with the biosensors for drugs, biomolecules, as well as biomarkers with smaller molecular weight, proteins, and infectious disease.


Assuntos
Técnicas Biossensoriais , Estruturas Metalorgânicas , Técnicas Eletroquímicas , Eletrodos , Estruturas Metalorgânicas/química , Metais
4.
Sensors (Basel) ; 20(11)2020 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-32521629

RESUMO

The notable toxicological impacts of aflatoxin B1 (AFB1) and its main metabolite, aflatoxin M1 (AFM1), on human being health make the evaluation of food quality highly significant. Due to the toxicity of those metabolites-even very low content in foodstuffs-it is crucial to design a sensitive and reliable procedure for their detection. Electrochemical aptamer-based biosensors are considered the most encouraging option, based on multi-placed analysis, rapid response, high sensitivity and specificity. The present review specifically emphasizes the potential utilization of the electrochemical aptasensors for determining the AFM1 and AFB1 with different electrodes.


Assuntos
Aflatoxina B1/análise , Aflatoxina M1/análise , Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Técnicas Eletroquímicas , Análise de Alimentos/métodos
5.
Sensors (Basel) ; 20(13)2020 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-32630056

RESUMO

Venlafaxine (VEN), as one of the popular anti-depressants, is widely utilized for the treatment of major depressive disorder, panic disorder, as well as anxiety. This drug influences the chemicals in the brain, which may result in imbalance in depressed individuals. However, venlafaxine and its metabolites are contaminants in water. They have exerted an adverse influence on living organisms through their migration and transformation in various forms of adsorption, photolysis, hydrolysis, and biodegradation followed by the formation of various active compounds in the environment. Hence, it is crucial to determine VEN with low concentrations in high sensitivity, specificity, and reproducibility. Some analytical techniques have been practically designed to quantify VEN. However, electroanalytical procedures have been of interest due to the superior advantages in comparison to conventional techniques, because such methods feature rapidity, simplicity, sensitivity, and affordability. Therefore, this mini-review aims to present the electrochemical determination of VEN with diverse electrodes, such as carbon paste electrodes, glassy carbon electrodes, mercury-based electrodes, screen-printed electrodes, pencil graphite electrodes, and ion-selective electrodes.


Assuntos
Antidepressivos/análise , Técnicas Eletroquímicas , Cloridrato de Venlafaxina/análise , Poluentes Químicos da Água/análise , Carbono , Eletrodos , Grafite , Reprodutibilidade dos Testes
6.
Sensors (Basel) ; 20(12)2020 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-32545829

RESUMO

In recent years, several studies have focused on environmental pollutants. Bisphenol A (BPA) is one prominent industrial raw material, and its extensive utilization and release into the environment constitute an environmental hazard. BPA is considered as to be an endocrine disruptor which mimics hormones, and has a direct relationship to the development and growth of animal and human reproductive systems. Moreover, intensive exposure to the compound is related to prostate and breast cancer, infertility, obesity, and diabetes. Hence, accurate and reliable determination techniques are crucial for preventing human exposure to BPA. Experts in the field have published general electrochemical procedures for detecting BPA. The present timely review critically evaluates diverse chemically modified electrodes using various substances that have been reported in numerous studies in the recent decade for use in electrochemical sensors and biosensors to detect BPA. Additionally, the essential contributions of these substances for the design of electrochemical sensors are presented. It has been predicted that chemically modified electrode-based sensing systems will be possible options for the monitoring of detrimental pollutants.


Assuntos
Compostos Benzidrílicos/análise , Técnicas Biossensoriais , Técnicas Eletroquímicas , Poluentes Ambientais/análise , Fenóis/análise , Eletrodos
7.
Environ Monit Assess ; 187(5): 257, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25877650

RESUMO

A novel carbon paste electrode modified with graphene oxide nanosheets and an ionic liquid (n-hexyl-3-methylimidazolium hexafluoro phosphate) was fabricated. The electrochemical study of the modified electrode, as well as its efficiency for voltammetric oxidation of bisphenol A, is described. The electrode was also employed to study the electrochemical oxidation of bisphenol A, using cyclic voltammetry, chronoamperometry, square wave voltammetry and electrochemical impedance spectroscopy as diagnostic techniques. Square wave voltammetry exhibits a linear dynamic range from 9.0 × 10(-8) to 2.5 × 10(-4) M and a detection limit of 55.0 nM for bisphenol A. Finally, this new sensor was used for determination of bisphenol A in water samples using the standard addition method.


Assuntos
Compostos Benzidrílicos/análise , Monitoramento Ambiental/instrumentação , Poluentes Ambientais/análise , Nanoestruturas , Fenóis/análise , Carbono/química , Eletrodos , Limite de Detecção , Oxirredução , Óxidos
8.
Environ Monit Assess ; 187(7): 407, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26045039

RESUMO

Hydrazine and phenol are two important environmental pollutants. In this work, an electrochemical sensor for the selective and sensitive detection of hydrazine in presence of phenol was developed by the bulk modification of carbon paste electrode (CPE) with TiO2 nanoparticles and Mn(III) salen. Large peak separation, good sensitivity, and stability allow this modified electrode to analyze hydrazine individually and simultaneously along with phenol. Applying square wave voltammetry (SWV), a linear dynamic range of 3 × 10(-8)-4.0 × 10(-4) M with detection limit of 10.0 nM was obtained for hydrazine. Finally, the proposed method was applied to the determination of hydrazine and phenol in some real samples.


Assuntos
Carbono/química , Etilenodiaminas/química , Hidrazinas/análise , Nanopartículas/química , Compostos Organometálicos/química , Fenol/análise , Titânio/química , Eletrodos , Monitoramento Ambiental , Limite de Detecção
9.
Environ Monit Assess ; 186(11): 7431-41, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25027778

RESUMO

The electrochemical oxidation of hydroxylamine on the surface of a carbon paste electrode modified with carbon nanotubes and 2,7-bis(ferrocenyl ethyl)fluoren-9-one is studied. The electrochemical response characteristics of the modified electrode toward hydroxylamine and phenol were investigated. The results showed an efficient catalytic activity of the electrode for the electro-oxidation of hydroxylamine, which leads to lowering its overpotential. The modified electrode exhibits an efficient electron-mediating behavior together with well-separated oxidation peaks for hydroxylamine and phenol. Also, the modified electrode was used for determination of hydroxylamine and phenol in some real samples.


Assuntos
Monitoramento Ambiental/métodos , Hidroxilamina/análise , Nanoestruturas/química , Fenol/análise , Carbono/química , Eletrodos , Monitoramento Ambiental/instrumentação , Modelos Químicos , Oxirredução
10.
Biosensors (Basel) ; 14(5)2024 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-38785703

RESUMO

In this work, UiO-66-NH2/GO nanocomposite was prepared using a simple solvothermal technique, and its structure and morphology were characterized using field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). An enhanced electrochemical sensor for the detection of epirubicin (EP) was proposed, which utilized a UiO-66-NH2/GO nanocomposite-modified screen-printed graphite electrode (UiO-66-NH2/GO/SPGE). The prepared UiO-66-NH2/GO nanocomposite improved the electrochemical performance of the SPGE towards the redox reaction of EP. Under optimized experimental conditions, this sensor demonstrates a remarkable limit of detection (LOD) of 0.003 µM and a linear dynamic range from 0.008 to 200.0 µM, providing a highly capable platform for sensing EP. Furthermore, the simultaneous electro-catalytic oxidation of EP and topotecan (TP) was investigated at the UiO-66-NH2/GO/SPGE surface utilizing differential pulse voltammetry (DPV). DPV measurements revealed the presence of two distinct oxidation peaks of EP and TP, with a peak potential separation of 200 mV. Finally, the UiO-66-NH2/GO/SPGE sensor was successfully utilized for the quantitative analysis of EP and TP in pharmaceutical injection, yielding highly satisfactory results.


Assuntos
Antineoplásicos , Técnicas Eletroquímicas , Eletrodos , Epirubicina , Grafite , Nanocompostos , Topotecan , Epirubicina/análise , Topotecan/análise , Grafite/química , Antineoplásicos/análise , Técnicas Biossensoriais , Estruturas Metalorgânicas/química , Limite de Detecção , Humanos , Oxirredução , Ácidos Ftálicos
11.
J AOAC Int ; 96(1): 204-11, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23513978

RESUMO

This paper describes the construction and performance characteristics of novel polyvinyl chloride membrane (PME) and coated platinum (CPtE) aluminium (Al) ion selective electrodes based on E-N'-(2-hydroxy-3-methoxybenzylidene) benzohydrazide. The electrodes exhibited linear responses with near Nernstian slopes of 19.9 +/- 0.3 (PME) and 20.1 +/- 0.4 (CPtE) mV/decade of activity within the Al3+ ion concentration range of 3.0 x 10(-7) to 1.0 x 10(-2) M for the PME and 1.0 x 10(-7)-1.0 x 10(-2) M for the CPtE. These sensors were applicable in a pH range of 3.0 to 7.0. The LODs of the PME and CPtE were 1.7 x 10(-7) and 5.6 x 10(-8) M, respectively. They had a response time of less than 10 s and could be used practically for a period of at least 2 months without measurable divergence in results. The isothermal temperature coefficient of the PME was 1.12 x 10(-3) V/degrees C, and it can tolerate partially nonaqueous media up to 25%. The electrodes showed excellent selectivity towards Al3+ ions in the presence of a wide range of alkali, alkaline earth, and transition metals ions. They were successfully applied for the direct determination of Al3+ ions in tap water, aqueduct water, mineral water, and Al-Mg syrup and as indicator electrodes in potentiometric titration of Al ions with EDTA.


Assuntos
Alumínio/análise , Compostos de Benzilideno/química , Hidrazinas/química , Platina/química , Cloreto de Polivinila/química , Potenciometria/métodos , Calibragem , Concentração de Íons de Hidrogênio , Eletrodos Seletivos de Íons , Membranas Artificiais , Temperatura
12.
Biosensors (Basel) ; 13(2)2023 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-36832010

RESUMO

The current attempt was made to detect the amino acid homocysteine (HMC) using an electrochemical aptasensor. A high-specificity HMC aptamer was used to fabricate an Au nanostructured/carbon paste electrode (Au-NS/CPE). HMC at high blood concentration (hyperhomocysteinemia) can be associated with endothelial cell damage leading to blood vessel inflammation, thereby possibly resulting in atherogenesis leading to ischemic damage. Our proposed protocol was to selectively immobilize the aptamer on the gate electrode with a high affinity to the HMC. The absence of a clear alteration in the current due to common interferants (methionine (Met) and cysteine (Cys)) indicated the high specificity of the sensor. The aptasensor was successful in sensing HMC ranging between 0.1 and 30 µM, with a narrow limit of detection (LOD) as low as 0.03 µM.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Nanopartículas Metálicas , Nanoestruturas , Técnicas Eletroquímicas/métodos , Ouro/química , Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , Nanopartículas Metálicas/química , Limite de Detecção , Eletrodos
13.
Nanomaterials (Basel) ; 13(3)2023 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-36770482

RESUMO

An ultrasensitive and selective voltammetric sensor with an ultratrace-level detection limit is introduced for ketoconazole (KTC) determination in real samples using a modified carbon paste electrode with a sheaf-like Ce-BTC MOF nanostructure and ionic liquid. The as-synthesized nanostructure was characterized by several techniques, including energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), 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), linear sweep voltammetry (LSV), and chronoamperometry. The limit of detection (LOD) of the developed sensor for KTC is 0.04 µM, and the response was found to be in the dynamic concentration range of 0.1-110.0 µM in a phosphate buffer solution. The proposed electrode exhibits acceptable electrocatalytic activity for KTC oxidation with a high sensitivity of 0.1342 µA·µM-1. The ability of the fabricated sensor to monitor KTC in real aqueous samples is demonstrated using standard addition data.

14.
Biosensors (Basel) ; 13(8)2023 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-37622900

RESUMO

Based on the modification of carbon paste electrode with NiCo2O4 nanoplates and 1-hexyl-3-methylimidazolium tetrafluoroborate, a new electrochemical sensing platform for the sensing of favipiravir (a drug with potential therapeutic efficacy in treating COVID-19 patients) in the presence of acetaminophen was prepared. For determining the electrochemical behavior of favipiravir, cyclic voltammetry, differential pulse voltammetry, and chronoamperometry have been utilized. When compared to the unmodified carbon paste electrode, the results of the cyclic voltammetry showed that the proposed NiCo2O4 nanoplates/1-hexyl-3-methylimidazolium tetrafluoroborate/carbon paste electrode had excellent catalytic activity for the oxidation of the favipiravir in phosphate buffer solution (pH = 7.0). This was due to the synergistic influence of 1-hexyl-3-methylimidazolium tetrafluoroborate (ionic liquid) and NiCo2O4 nanoplates. In the optimized conditions of favipiravir measurement, NiCo2O4 nanoplates/1-hexyl-3-methylimidazolium tetrafluoroborate/carbon paste electrode had several benefits, such as a wide dynamic linear between 0.004 and 115.0 µM, a high sensitivity of 0.1672 µA/µM, and a small limit of detection of 1.0 nM. Furthermore, the NiCo2O4 nanoplates/1-hexyl-3-methylimidazolium tetrafluoroborate/carbon paste electrode sensor presented a good capability to investigate the favipiravir and acetaminophen levels in real samples with satisfactory recoveries.


Assuntos
COVID-19 , Líquidos Iônicos , Humanos , Acetaminofen , Carbono
15.
Micromachines (Basel) ; 14(7)2023 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-37512744

RESUMO

Food colorants are important in food selection because they improve the gastronomic appeal of foods by improving their aesthetic appeal. However, after prolonged use, many colorants turn toxic and cause medical problems. A synthetic azo-class dye called carmoisine gives meals a red color. Therefore, the carmoisine determination in food samples is of great importance from the human health control. The current work was developed to synthesis ZnO hollow quasi-spheres (ZnO HQSs) to prepare a new electrochemical carmoisine sensor that is sensitive. Field emission-scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) have been used to analyze the properties of prepared ZnO HQSs. A screen-printed graphite electrode (SPGE) surface was modified with ZnO HQSs to prepare the ZnO HQSs-SPGE sensor. For carmoisine detection, the ZnO HQSs-SPGE demonstrated an appropriate response and notable electrocatalytic activities. The carmoisine electro-oxidation signal was significantly stronger on the ZnO HQSs-SPGE surface compared to the bare SPGE. Cyclic voltammetry (CV), linear sweep voltammetry (LSV), chronoamperometry (CHA), and differential pulse voltammetry (DPV) have been utilized to investigate the suggested protocol. The DPV results revealed an extensive linear association between variable carmoisine concentrations and peak current that ranged from 0.08 to 190.0 µM, with a limit of detection (LOD) as narrow as 0.02 µM. The ZnO HQSs-SPGE's ability to detect carmoisine in real samples proved the sensor's practical application.

16.
Food Chem Toxicol ; 165: 113048, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35523384

RESUMO

The sunset yellow, as a synthetic food coloring azo dye, was detected in the present work using a new sensitive and selective sensor based on the modification of screen-printed electrode surface with Copper ferrite nanoparticles (CuFe2O4/SPE). Thus, a facile hydrothermal protocol was performed to prepare the CuFe2O4 nanoparticles, followed by characterization applying valid techniques, including Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and field-emission scanning electron microscopy (FE-SEM). Chronoamperometry, differential pulse voltammetry (DPV) and cyclic voltammetry (CV) were employed to determine the electrochemical behavior of as-fabricated sensor. According to the electrochemical findings, a greater anodic peak current was found for the sunset yellow oxidation on the CuFe2O4/SPE than that on the unmodified SPE. The electrocatalytic response for the sunset yellow oxidation on the CuFe2O4/SPE in phosphate buffer (0.1 M, pH = 7.0) was effective, with an excellent sensitivity (0.1919 µA µM-1). There was a linear relationship between the voltammetric current and different sunset yellow concentrations (0.03-100.0 µM). The calculated limit of detection (LOD = 3Sb/m) for the sunset yellow was 0.009 µM.


Assuntos
Técnicas Eletroquímicas , Nanopartículas , Compostos Azo , Técnicas Eletroquímicas/métodos , Eletrodos , Nanopartículas/química , Espectroscopia de Infravermelho com Transformada de Fourier
17.
Micromachines (Basel) ; 13(4)2022 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-35457903

RESUMO

The current work introduced a convenient single-phase hydrothermal protocol to fabricate MnO2 nanorods (MnO2 NRs). Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX) and field-emission scanning electron microscopy (FE-SEM) were used to determine the characteristics of MnO2 NR. Then, ionic liquid (IL) and MnO2 NRs were utilized to modify a carbon paste electrode (CPE) surface (MnO2NR-IL/CPE) to voltammetrically sense the sulfanilamide (SAA). An enhanced voltammetric sensitivity was found for the as-developed modified electrode toward SAA when compared with a bare electrode. The optimization experiments were designed to achieve the best analytical behavior of the SAA sensor. Differential pulse voltammetry (DPV) in the optimized circumstances portrayed a linear dependence on various SAA levels (between 0.07 and 100.0 µM), possessing a narrow detection limit (0.01 µM). The ability of the modified electrode to be used in sensor applications was verified in the determination of SAA present in the actual urine and water specimens, with impressive recovery outcomes.

18.
Biosensors (Basel) ; 12(11)2022 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-36354421

RESUMO

The current work was performed to construct a novel electrochemical sensing system for determination of sunset yellow via the modification of screen-printed graphite electrode modified with hierarchical flower-like NiCo2O4 nanoplates (NiCo2O4/SPGE). The prepared material (hierarchical flower-like NiCo2O4 nanoplates) was analyzed by diverse microscopic and spectroscopic approaches for the crystallinity, composition, and morphology. Chronoamperometry, differential pulse voltammetry, linear sweep voltammetry, and cyclic voltammetry were used for determination of the electrochemical behavior of sunset yellow. The as-fabricated sensor had appreciable electro-catalytic performance and current sensitivity in detecting the sunset yellow. There were some advantages for NiCo2O4/SPGE under the optimized circumstances of sunset yellow determination, including a broad dynamic linear between 0.02 and 145.0 µM, high sensitivity of 0.67 µA/(µM.cm2), and a narrow limit of detection of 0.008 µM. The practical applicability of the proposed sensor was verified by determining the sunset yellow in real matrices, with satisfactory recoveries.


Assuntos
Técnicas Eletroquímicas , Grafite , Técnicas Eletroquímicas/métodos , Compostos Azo , Grafite/química , Eletrodos
19.
Chemosphere ; 291(Pt 3): 132736, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34728224

RESUMO

The purpose of this study was to fabricate an electrochemical sensor for the detection of methotrexate and folic acid based on a screen-printed graphite electrode (SPGE) modified with prepared iron oxide (Fe3O4)/polypyrrole (ppy)/Palladium (Pd) nanocomposite. Transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR) techniques were employed to characterize the Fe3O4/ppy/Pd nanocomposite. The produced modifier was used to induce a remarkable electrocatalytic impact relative to the oxidation of methotrexate, which caused the potential peak shift to a less positive amount (from 800 mV to about 500 mV) and improved the peak current (from 5.3 µA to about 16 µA). Methotrexate peak current was linearly dependent on its concentration from 0.03100.0 µM and the limit of detection (LOD) was estimated at 7.0 nM. The methotrexate and folic acid were co-detected by the proposed sensor. The experimental results indicated that the oxidation peaks of methotrexate and folic acid were separated about 200 mV in phosphate buffer solution (PBS) at pH 7.0. Fe3O4/ppy/Pd/SPGE was successfully able to detect methotrexate and folic acid in pharmaceutical and biological samples with excellent recovery.


Assuntos
Grafite , Nanocompostos , Preparações Farmacêuticas , Técnicas Eletroquímicas , Eletrodos , Ácido Fólico , Metotrexato , Paládio , Polímeros , Pirróis , Espectroscopia de Infravermelho com Transformada de Fourier
20.
Food Chem Toxicol ; 167: 113274, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35843424

RESUMO

The present research presents synthesis and substantial utilization of a nanocomposite of reduced graphene oxide/polypyrrole nanotubes to modify graphite screen printed electrode (rGO/PPy NTs-GSPE) for detection of sulfite. The nanocomposite preparation was done by hydrothermal protocol, followed by characterization by energy-dispersive X-ray (EDX) and field emission-scanning electron microscopy (FE-SEM). Electrocatalytic sensing of sulfite is carried out using differential pulse voltammetric (DPV), linear sweep voltammetry (LSV), cyclic voltammetric (CV), and Chronoamperometry. Electrochemical behaviors of modified and unmodified electrodes were explored with CV method. In addition, DPV was employed for anodic peak and quantitatively detecting sulfite. The DPV results unveiled a linear response of the sensor to various sulfite contents (0.04-565.0 µM) with a narrow detection limit (0.01 µM) and admirable sensitivity (0.0483 µA/µΜ). The diffusion coefficient (D) for sulfite using rGO/PPy NTs-GSPE, 9.9 × 10-6 cm 2/s was obtained. The sensor was also successful in the sulfite detection in real specimens.


Assuntos
Grafite , Nanocompostos , Nanotubos , Técnicas Eletroquímicas/métodos , Eletrodos , Grafite/química , Nanocompostos/química , Polímeros , Pirróis , Sulfitos
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