Sensitive Detection of Human Hemoglobin by MWCNTs-ionic Liquid: Anthraquinone Modified Electrode

2019 ◽  
Vol 9 (4) ◽  
pp. 479-485
Author(s):  
Aghdas Banaei ◽  
Mostafa Shourian ◽  
Fariba Dashtestani ◽  
Khadijeh Eskandari
Keyword(s):  
Ionic Liquid ◽  
Modified Electrode ◽  
Clinical Sample ◽  
Phosphate Buffer Solution ◽  
Cyclic Voltammograms ◽  
Buffer Solution ◽  
Solution Ph ◽  
Nano Composite ◽  
Composite Gels ◽  
Composite Gel

Introduction: Today, nano-composite gels based on multi-walled carbon nanotubes in room temperature ionic liquid (MWCNTs-IL-Gel) are an interesting subject. Materials and Methods: The nano-composite gels showed convenient electrochemical properties against redox activities of electroactive biomolecules. Also, the evaluation of hemoglobin concentration is a critical point in the clinical sample. So, the kind of nano-composite gel which is composed of NH2 functionalized MWCNTs and [amim] Br IL and anthraquinone 2-carboxilic acid (AQ) was fabricated and applied in electrochemical detection of hemoglobin. Cyclic voltammograms of NH2.MWCNTs-IL-AQ modified electrode exhibited redox peak sat -0.5 V (vs. Ag/AgCl) in 0.1 M phosphate buffer solution ((pH 7.0). Results: As the hemoglobin added into the measured solution, the redox current decreased. Conclusion: It can be concluded that the increment in the concentration of hemoglobin caused the decrease in the redox currents in cyclic voltammetry. The NH2.MWCNTs-IL-AQ would detect the concentration of hemoglobin from 1.64 x10−8 to 4.89x10−7 M.

Selective Voltammetric Detection of Dopamine in the Presence of Ascorbic Acid at Poly(p-methoxyphenol)-Modified Electrode

2020 ◽  
Vol 18 (3) ◽  
pp. 222-226
Author(s):  
Gamze Erdoğdu
Keyword(s):  
Ascorbic Acid ◽  
Detection Limit ◽  
Modified Electrode ◽  
Oxidative Polymerization ◽  
Phosphate Buffer Solution ◽  
Relative Sensitivity ◽  
High Concentration ◽  
Buffer Solution ◽  
Solution Ph ◽  
Voltammetric Detection

A gold electrode was modified with electropolymerized films of p-methoxyphenol by its oxidative polymerization from an alkaline solution by cyclic voltammetry. The modified electrode was then used to determine dopamine (DA) in the presence of a high concentration of ascorbic acid (AA) by differential pulse voltammetry. The peak positions as well as relative sensitivity DA/AA were affected by the potential window used for the polymerization. For polymerization between 0 and 1.0 V, the peak potentials recorded in a phosphate buffer solution (pH = 7.2) were 516 and 312 mV versus Ag/AgCl for DA and AA, respectively. In addition to the effects of pH and the type of electrolyte on the linearity range and detection limit are investigated. The detection limit for 3s-test is 0.1 nM. The high selectivity and sensitivity for DA was found to be due to charge discrimination/analyte accumulation.

scholarly journals Electrochemical Polymerised Graphene Paste Electrode and Application to Catechol Sensing

2019 ◽  
Vol 13 (1) ◽  
pp. 81-87 ◽  
Author(s):  
Jamballi G. Manjunatha
Keyword(s):  
Modified Electrode ◽  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Sample Pretreatment ◽  
Differential Pulse ◽  
Buffer Solution ◽  
Solution Ph ◽  
Graphene Paste Electrode ◽  
Paste Electrode

Objective: To build up an advantageous strategy for sensitive determination of catechol (CC), a poly (proline) modified graphene paste electrode (PPMGPE) was fabricated and used as a voltammetric sensor for the determination of CC. Methods: The performance of the modified electrode was studied using cyclic voltammetric (CV) and differential pulse voltammetric method (DPV). The modified electrode was characterized by CV and DPV. The surface of the modified electrode was examined by FESEM. The electrochemical behavior of CC in phosphate buffer solution (pH 7.5) was inspected using bare graphene paste electrode (BGPE) and PPMGPE. Results & Conclusion: The PPMGPE shows a lower limit of detection, calculated to be 8.7×10–7mol L−1 (S/N=3). This modified electrode was applied successfully for the determination of CC in water samples without applying any sample pretreatment.

Detection of Hepatitis a Virus in Drinking Water by Enzyme -Immunoassay Using Ultracentrifugation for Virus Concentration

1985 ◽  
Vol 17 (10) ◽  
pp. 39-41 ◽  
Author(s):  
A. Schnattinger
Keyword(s):  
Membrane Filtration ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Solid Phase ◽  
Phosphate Buffer Solution ◽  
Enzyme Linked Immunosorbent Assay ◽  
Virus Concentration ◽  
Buffer Solution ◽  
Solution Ph ◽  
Two Stage

Ten litres of tapwater were seeded with 200 µl (8×108 HAV particles) of a commercial (Organon Teknika) suspension of hepatitis A virus. Following WALTER and RÜDIGER (1981), the contaminated tapwater was treated with a two-stage technique for concentration of viruses from solutions with low virus titers. The two-stage technique consists of aluminium hydroxideflocculation (200 mg/l Al2(SO4)3. 18 H2O, pH 5,4-5,6) as first stage, the second stage of a lysis of aluminium hydroxidegel with citric acid/sodium citrate-buffer (pH 4,7; 1 ml/l sample), separation of viruses from the lysate by ultracentrifugation and suspension in 1 ml phosphate buffer solution (pH 7,2). A commercial solid phase enzyme-linked immunosorbent assay (ELISA) was used for the detection of HAV. HAV was detecterl in the 10.000:1 concentrates, but not in the seeded 101 samples. Approximately 4×108 of the inoculated 8×108 HAV particles were found in the 1 ml concentrates. The efficiency of detection is about 50%, the virus concentration 5000-fold. Although the percentage loss of HAV in comparison with concentration by means of membrane filtration is similar, the ultracentrifugation method yields a larger sample/concentrate ratio, so that smaller amounts of HAV can be detected more efficiently because of the smaller end-volume.

Non-enzymatic determination of purine nucleotides using a carbon dot modified glassy carbon electrode

2019 ◽  
Vol 11 (30) ◽  
pp. 3866-3873 ◽  
Author(s):  
R. Karthikeyan ◽  
D. James Nelson ◽  
S. Abraham John
Keyword(s):  
Glassy Carbon ◽  
Low Cost ◽  
Phosphate Buffer Solution ◽  
Purine Nucleotides ◽  
Buffer Solution ◽  
Solution Ph ◽  
Carbon Dot ◽  
Enzymatic Determination ◽  
Sensitive Determination

Selective and sensitive determination of one of the purine nucleotides, inosine (INO) using a low cost carbon dot (CD) modified glassy carbon (GC) electrode in 0.2 M phosphate buffer solution (pH 7.2) was demonstrated in this paper.

scholarly journals Electro-Polymerized Titan Yellow Modified Carbon Paste Electrode for the Analysis of Curcumin

Surfaces ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 191-204
Author(s):  
Edwin S. D’Souza ◽  
Jamballi G. Manjunatha ◽  
Chenthattil Raril ◽  
Girish Tigari ◽  
Huligerepura J. Arpitha ◽  
...  
Keyword(s):  
Carbon Paste Electrode ◽  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Modified Carbon Paste Electrode ◽  
Carbon Paste ◽  
Buffer Solution ◽  
Solution Ph ◽  
Real Sample Analysis ◽  
Titan Yellow ◽  
Paste Electrode

A modest, efficient, and sensitive chemically modified electrode was fabricated for sensing curcumin (CRC) through an electrochemically polymerized titan yellow (TY) modified carbon paste electrode (PTYMCPE) in phosphate buffer solution (pH 7.0). Cyclic voltammetry (CV) linear sweep voltammetry (LSV) and differential pulse voltammetry (DPV) approaches were used for CRC detection. PTYMCPE interaction with CRC suggests that the electrode exhibits admirable electrochemical response as compared to bare carbon paste electrode (BCPE). Under the optimized circumstances, a linear response of the electrode was observed for CRC in the concentration range 2 × 10−6 M to 10 × 10−6 M with a limit of detection (LOD) of 10.94 × 10−7 M. Moreover, the effort explains that the PTYMCPE electrode has a hopeful approach for the electrochemical resolution of biologically significant compounds. Additionally, the proposed electrode has demonstrated many advantages such as easy preparation, elevated sensitivity, stability, and enhanced catalytic activity, and can be successfully applied in real sample analysis.

Controlled Release of Active Substance from Biodegradable Copolymer Matrix

2006 ◽  
Vol 510-511 ◽  
pp. 798-801
Author(s):  
Hyung Suk So ◽  
Hyun Chul Shin ◽  
Beom Suk Kim ◽  
Yeong Seok Yoo
Keyword(s):  
Methylene Blue ◽  
Active Substance ◽  
Phosphate Buffer Solution ◽  
Ultra Violet ◽  
Hydroxyl Groups ◽  
Buffer Solution ◽  
Solution Ph ◽  
Effective Discharge ◽  
Constant Rate ◽  
Long Time

The purpose of this study is to develop a new system to control effective discharge of active substances such as agricultural chemicals. To synthesize a naturally dissolvable polymer; ε-caprolactone and diglycolide were copolymerized with ethylene glycol as an initiator to produce macrodiol. As macrodiol has hydroxyl groups in both ends, they are modified with methacryloyl chloride for photochemical networking. After standard macromonomer produced by this procedure was physically mixed with methylene blue, it was networked with ultra-violet rays to be filmed. This film is naturally dissolvable and hydrolytic. As a result of hydrolytic test with a crosslinked structure of 10 % methylene blue, it decreased by 9 % for seven weeks in 37 °C phosphate buffer solution (pH = 7). Thus, we verified that active substance can be discharged from a crosslinked structure for a long time at a constant rate under room temperature.

OPTIMISATION AND VALIDATION OF HPLC METHOD FOR SIMULTANEOUS QUANTIFICATION OF RIFAMPICIN, ISONIAZID, PYRAZINAMIDE, AND ETHAMBUTOL HYDROCHLORIDE IN ANTI-TUBERCULOSIS 4-FDC TABLET

2015 ◽  
Vol 77 (1) ◽  
Author(s):  
Sholihul Khoiri ◽  
Sudibyo Martono ◽  
Abdul Rohman
Keyword(s):  
High Performance ◽  
Phosphate Buffer Solution ◽  
Gradient Elution ◽  
Hplc Method ◽  
Fixed Dose ◽  
Buffer Solution ◽  
Solution Ph ◽  
Combination Tablet ◽  
Simultaneous Quantification ◽  
Dose Combination

High-performance liquid chromatography (HPLC) method has been developed and validated for the simultaneous quantification of four components, namely rifampicin (RIF), isoniazid (INH), pyrazinamide (PYR), and ethambutol hydrochloride (ETM), contained in anti-tuberculosis drugs in fixed dose combination tablet (4-FDC). In order to increase the sensitivity of EMB, the pre-column derivatization technique with phenethyl isocyanate (PEIC) was carried out. The separation was accomplished using Waters Symmetry C8 (250× 4.6 mm i.d.; 5 μm) at 30oC. The mobile phase used was a mixture of acetonitrile and 20 mM phosphate buffer solution (pH 6.8) containing triethylamine and delivered at 1.5 mL/minute using gradient elution. TheUV detector was set at 210 nm. The method was validated in terms of selectivity, linearity, accuracy, precision, detection limit, quantification limit, and robustness according to International Conference on Harmanization (ICH). The optimized method is succcesfully used for quantitative analysis of RIF, INH, PYR and ETM in 4-FDC tablets. The level of these drugs in 4-FDC tablets were in accordance to that specified in Indonesian pharmacopeia.

The Study of Albumin Release from Silica/Albumin as a Potential Drug Delivery Carrier

2014 ◽  
Vol 69 (5) ◽  
Author(s):  
Shafiyah Pondi ◽  
Jon Efendi ◽  
Ho Chin Siong ◽  
Lai Sin Yuan ◽  
Sheela Chandren ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Fumed Silica ◽  
In Vitro Release ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Solution Ph ◽  
Drug Delivery Carrier ◽  
High Interaction ◽  
Uv Visible

The drug-delivery field has been an attractive as well as challenging area for research. With the emerging of new formulated drugs and pharmaceutical compounds, development of good drug-delivery system (DDS) is crucially required. This study aims to utilize albumin as the drug template in silica/albumin/drug (S/A/D) system. Prior to designing this system, the interaction between silica and albumin was investigated. It is hypothesized that high interaction between silica and albumin may result in slower drug release over time, which is preferred for a good DDS. Silica and albumin (S/A) materials were prepared by using fumed silica and tetraethyl orthosilicate (TEOS) as the silica precursors. Three different S/A samples were prepared; fumed silica with albumin (FS/A), fumed silica with pre-treated albumin by sodium borohydrate (FS/A-N), and silica sol (TEOS) with albumin (SS/A). In-vitro release of albumin in phosphate buffer solution (pH 7) was carried out to examine the interaction between albumin and silica. The concentration of albumin was detected at 280 nm by UV-visible spectrophotometer. All samples were characterized by diffuse reflectance-UV-visible spectrophotometer (DR-UV), Fourier transform infrared spectrophotometer (FTIR) dan thermogravimetric-differential thermal analysis (TG-DTA). DR-UV results show that SS/A exhibited the lowest absorption intensity at 280 nm, which indicates better interaction between silica and albumin. This result was supported by the presence of Si-O stretching band of silanol at 952 cm-1 from the FTIR spectrum. Release study of albumin demonstrated that the release of albumin from SS/A was slowest compared to those of FS/A and FS/A-N. 

scholarly journals Color Stability of Phycoerythrin Crude Extract (PECE) from Rhodomonas Salina Toward Physicochemical Factors

2019 ◽  
Vol 14 (1) ◽  
pp. 21
Author(s):  
Endar Marraskuranto ◽  
Tri Joko Raharjo ◽  
Rina Sri Kasiamdari ◽  
Tri Rini Nuringtyas
Keyword(s):  
Phosphate Buffer Solution ◽  
Color Stability ◽  
Ethanol Solution ◽  
Future Application ◽  
Buffer Solution ◽  
Solution Ph ◽  
Rhodomonas Salina ◽  
Freeze Dried ◽  
Physicochemical Factors ◽  
The Stability

Rhodomonas salina produces Cr-phycoerythrin545 as its designated phycoerythrin (PE) with an absorption maximum at 545 nm and a shoulder 564 nm. PE has potential to be applied as colorants, pharmaceutical agents, and fluorescent dye tags. The stability of the PE color is influenced by the physicochemical factors of the solution. This study aimed to analyze the color stability of PECE against chemical (ethanol and pH) and physical (light and temperature) factors. PECE was prepared from freeze-dried biomass of R. salina and was extracted in phosphate buffer solution (pH = 6.0) using a freeze-thaw method in -25 oC (2 hours) and 4 oC (24 hours). The resulting extract was concentrated and dried in a freeze-dryer. Analyses were conducted using UV-visible and fluorescence spectrophotometer. PECE showed color stability against light of white fluorescent lamp exposure up to 8 hours, temperature exposure up to 40 oC, ethanol solution up to concentration of 20 % (v/v), and pH range 3.9-8.42. Results from this study can be useful for extraction, purification, and future application of Cr-PE545.

scholarly journals Polyaniline-Invertase-Gold Nanoparticles Modified Gold Electrode for Sucrose Detection

2015 ◽  
Vol 15 (3) ◽  
pp. 226-233 ◽  
Author(s):  
Fitriyana Fitriyana ◽  
Fredy Kurniawan
Keyword(s):  
Gold Nanoparticles ◽  
Gold Electrode ◽  
Sucrose Solution ◽  
Sucrose Concentration ◽  
Phosphate Buffer Solution ◽  
Layer By Layer ◽  
Buffer Solution ◽  
Solution Ph ◽  
Active Materials ◽  
Aniline Polymerization

Sucrose sensor has been made by deposited the active materials on the surface of gold electrode. The active materials, i.e. polyaniline (PANI), invertase and gold nanoparticles, were deposited step by step. Aniline polymerization were conducted electrochemically at potential -500 to 1000 mV using voltammetry method with sweep rate 50 mV/s for 20 cycles in HCl solution pH 1.5. The modified electrode obtained was immersed in invertase 1 M phosphate buffer solution pH 6. The invertase trapping in polyaniline was performed using the same condition as aniline polymerization. Then, gold nanoparticles were deposited on the polyaniline-invertase modified gold electrode using Layer by Layer (LbL) technique. The polyaniline-invertase-gold nanoparticles modified gold electrode obtained was used to measure sucrose solution. Electrochemical signal of polyaniline (PANI)-invertase-gold nanoparticles modified gold electrode is increase with sucrose concentration. The sensitivity and detection limit of the electrode are 0.4657 µA mm-2 mM-1 and 9 µM, respectively. No electrochemical interference signals from fructose and glucose have been observed in the sucrose measurement.

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