scholarly journals The effect of aldehyde fixation on selected substrates for energy metabolism and amino acids in mouse brain.

1978 ◽  
Vol 26 (6) ◽  
pp. 423-433 ◽  
Author(s):  
K A Conger ◽  
J H Garcia ◽  
A S Lossinsky ◽  
F C Kauffman
Keyword(s):  
Amino Acids ◽  
Initial Period ◽  
Operative Procedure ◽  
Light And Electron Microscopy ◽  
Phosphate Buffer Solution ◽  
Fold Increase ◽  
Buffer Solution ◽  
Aldehyde Fixation ◽  
Excellent Preservation

The effect of aldehyde fixation on concentrations of low molecular weight constituents was determined by comparing amounts of selected intermediates in brains of mice exposed to aldehyde fixative solutions with those perfused with phosphate buffer solution alone. Aldehyde perfusion resulted in excellent preservation of cerebral cortex ultrastructure in the presence of dramatic declines in adenosine triphosphate, phosphocreatine, glucose and glucose-6-phosphate that occureed before exposure of the tissue to aldehyde fixatives. Decreases in hexose were accompanied by approximately a 4-fold increase in lactate and a 2-fold increase in pyruvate. Glycogen levels decreased by about 60% during the initial operative procedure but remained constant after aldehyde fixation. Glycogen content declined approximately 90% in tissues that were not treated with aldehyde. Concentrations of aspartate and glutamate changed only slightly during the initial period (1-5 min) and remained constant for at least 90 min in cerebral cortices fixed with aldehydes. Alanine levels increased in both fixed and unfixed tissue; however, this increase was much smaller in tissues exposed promptly to aldehydes. Total ninhydrin-positive material in perchloric acid extracts of brain decreased in mice exposed to aldehyde solutions but increased in tissues that were not. These results indicated that several amino acids may be measured reliably in tissues preserved for light and electron microscopy. In addition, determination of glutamate: alanine ratios in tissues perfused with aldehydes may provide an indication of the timing of fixation.

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.

Development and Validation of HPLC Determination of related Substances in A Novel Anticonvulsant agent Epimidin

2021 ◽  
pp. 3223-3231
Author(s):  
Hanna I. Severina ◽  
Svitlana M. Gubar ◽  
Ivan V. Bezruk ◽  
Anna S. Materiienko ◽  
Liudas Ivanauskas ◽  
...  
Keyword(s):  
Mobile Phase ◽  
Phosphate Buffer Solution ◽  
Anticonvulsant Drug ◽  
Strong Acid ◽  
Gradient Elution ◽  
Stress Conditions ◽  
Drug Candidate ◽  
Buffer Solution ◽  
Related Substances

1-(4-methoxyphenyl)-5-[2-[4-(4-methoxyphenyl)piperazin-1-yl]-2-oxo-ethyl]pyrazolo[3,4-d]pyrimidin-4-one has been reported as a promising new anticonvulsant drug candidate with a code name “Epimidin”. A new HPLC method for the related substances determination of potential active pharmaceutical ingredient has been developed and validated. The method uses ACE C18 column (250x4.6mm, 5µm) and gradient elution. Mobile phase consisted of a mixture of methanol R (mobile phase A) and phosphate buffer solution with triethanolamine, adjusted to pH 7.0 (mobile phase B). During the analysis, the ratio of mobile phases was changing according to a gradient mode at a flow rate of 1ml/min. The DAD detection was set at 240nm. The method was validated according to the ICH guidelines and requirements of State Pharmacopoeia of Ukraine. Drug substance was thoroughly explored for stability assessments under various stress conditions such as high temperature, as well as the influence of strong acid and base and oxidizing agents. The obtained solutions were analyzed by HPLC and LC/MS. It has been shown that the substance Epimidin was not resistant to the action of peroxide, alkali and acid decomposition – the mentioned stress conditions lead to the formation of unidentified impurities.

scholarly journals Carvacrol electrochemical reaction characteristics on screen printed electrode modified with La2O3/Co3O4 nanocomposite

2019 ◽  
Vol 9 (2) ◽  
pp. 113-123 ◽  
Author(s):  
Sayed Zia Mohammadi ◽  
Hadi Beitollahi ◽  
Tahereh Rohani ◽  
Hossein Allahabadi
Keyword(s):  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Co3o4 Nanoparticles ◽  
Electrochemical Characteristics ◽  
Screen Printed Electrode ◽  
Buffer Solution ◽  
Voltammetric Techniques ◽  
Screen Printed

Electrochemical characteristics of carvacrol were investigated on a screen-printed electrode (SPE) modified with La2O3/Co3O4 nanocomposite by using voltammetric techniques, which displayed a well-defined peak for sensitive carvacrol determination in phosphate buffer solution (PBS) at pH 7.0. La2O3/Co3O4 nanoparticles demonstrated suitable catalytic activity for carvacrol determination by differential pulse voltammetry (DPV) technique. Besides, determination of carvacrol in a real samples was recognized in the light of electrochemical findings and a validated voltammetric technique for quantitative analysis of carvacrol in a real formulation was proposed. The DPV peak currents were found to be linear in the concentration range of 10.0 to 800.0 μM. The limit of detection (LOD) was found to be 1.0 μM.

Microwave-assisted synthesis of NaA nanozeolite from slag and performance of Ag-doped nanozeolite as an efficient material for determination of hydrogen peroxide

RSC Advances ◽  
2016 ◽  
Vol 6 (57) ◽  
pp. 52058-52066 ◽  
Author(s):  
Seyed Naser Azizi ◽  
Shahram Ghasemi ◽  
Mehrnaz Mikhchian
Keyword(s):  
Hydrogen Peroxide ◽  
Phosphate Buffer Solution ◽  
Modified Carbon Paste Electrode ◽  
Microwave Assisted Synthesis ◽  
Carbon Paste ◽  
Buffer Solution ◽  
Microwave Assisted ◽  
And Performance ◽  
Paste Electrode

A new amperometric sensor is prepared based on a Ag doped NaA nanozeolite modified carbon paste electrode (Ag/ACPE) in order to detect hydrogen peroxide (H2O2) in phosphate buffer solution (PBS, pH 7.0).

Electrocatalytic performance of a zinc sulphide nanoparticles-modified carbon paste electrode for the simultaneous determination of acetaminophen, guanine and adenine

2018 ◽  
Vol 10 (11) ◽  
pp. 1362-1371 ◽  
Author(s):  
Mallappa Mahanthappa ◽  
Nagaraju Kottam ◽  
Shivaraj Yellappa
Keyword(s):  
Carbon Paste Electrode ◽  
Phosphate Buffer ◽  
Phosphate Buffer Solution ◽  
Zinc Sulphide ◽  
Modified Carbon Paste Electrode ◽  
Carbon Paste ◽  
Buffer Solution ◽  
Guanine And Adenine ◽  
Paste Electrode

The simultaneous electroanalysis of acetaminophen (AC), guanine (G) and adenine (A) was successfully achieved on the zinc sulphide nanoparticles-modified carbon paste electrode (ZnS NPs/CPE) in phosphate buffer solution (PBS).

Gas Chromatographic/Mass Spectrometric Determination of Erythromycin in Beef and Pork

1987 ◽  
Vol 70 (4) ◽  
pp. 708-713
Author(s):  
Keigo Takatsuki ◽  
Shigeru Suzuki ◽  
Nobutoshi Sato ◽  
Isamu Ushizawa ◽  
Takuro Shoji
Keyword(s):  
Room Temperature ◽  
Phosphate Buffer Solution ◽  
Mass Spectrometric ◽  
Buffer Solution ◽  
Residual Level ◽  
Electron Impact Mass ◽  
Full Scan ◽  
Impact Mass ◽  
Chromatographic Mass

Abstract A gas chromatographic/mass spectrometric (GC/MS) method is described for the determination of residual erythromycin in beef and pork. This method allows detection and quantitation of residual erythromycin in beef and pork by using single-ion monitoring; confirmation by a full scan electron impact mass spectrum is possible if residual level in a sample is ≥ 1 ppm. Erythromycin is extracted with methanol from a sample and cleaned up by n-hexane washing followed by partition between chloroform and phosphate buffer solution. The cleaned up extract is chromatographed on a silica gel column, acid hydrolyzed, and acetylated in acetic anhydride-pyridine mixture (1 + 2) at room temperature. The reaction mixture is injected into the GC/MS apparatus, and detection and quantitation are conducted using single-ion monitoring at m/z 200. The recoveries (CV, %) at 1 and 0.1 ppm fortification levels are 86% (2.7%) and 72% (7.7%), and the detection limit is 0.01 ppm.

Fabrication of Graphene/Carbon Nanotube Composite Modified Electrode for Selective and Sensitive Determination of Uric Acid

2013 ◽  
Vol 641-642 ◽  
pp. 562-565
Author(s):  
Zheng Xiao Liu ◽  
Jian Fei Xia ◽  
Zong Hua Wang ◽  
Yan Zhi Xia ◽  
Fei Fei Zhang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Uric Acid ◽  
Carbon Nanotube ◽  
Modified Electrode ◽  
Phosphate Buffer Solution ◽  
Carbon Electrode ◽  
Buffer Solution ◽  
Sensitive Determination ◽  
Carbon Nanotube Composite

A novel composite was firstly synthesized by compositing graphenes (G) and carbon nanotubes (CNTs) and then a new composite modified electrode (G/CNTs/GCE) was prepared by coating the resulting composite on the surface of the glassy carbon electrode (GCE). The composite modified electrode G/CNTs/GCE showed great electrochemical activities which were studied by sensitive determining the electrochemistry behaviors of uric acid (UA). It revealed when the concentration range of UA changed from 1×10-7 mol/L to 1×10-3 mol/L, the peak currents had linear relationship with the concentration of UA in the phosphate buffer solution (PBS) which the value of pH is 7.0. And the linear equation is ip (μA) = 21.55C+28.94 (C: mmol/L), with the related coefficient 0.9964.

A Simple and Sensitive Voltammetric Method for the Determination of Orange II Based on a Functionalized Graphene-Modified Electrode

2016 ◽  
Vol 99 (5) ◽  
pp. 1287-1294 ◽  
Author(s):  
Yudong Gao ◽  
Zhengkun Xie ◽  
Yulong Zhang ◽  
Lina Zou ◽  
Baoxian Ye
Keyword(s):  
Phosphate Buffer Solution ◽  
Linear Sweep Voltammetry ◽  
Food Samples ◽  
Orange Ii ◽  
Voltammetric Sensor ◽  
Functionalized Graphene ◽  
Modified Glassy Carbon Electrode ◽  
Buffer Solution ◽  
Accumulation Ability

Abstract A simple and sensitive voltammetric sensor for Orange II was developed, based on a poly(sodium p-styrenesulfonate)-functionalized graphene-modified glassy carbon electrode. This voltammetric sensor showed strong accumulation ability and an excellent voltammetric response for Orange II. The electrochemical behavior of Orange II was systematically investigated in a pH 7.0 phosphate buffer solution. By linear sweep voltammetry, under optimum conditions, a good linear relationship was obtained between peak currents and Orange II concentrations in the wider range of 3 × 10−8 to 5 × 10−6 mol/L, with an LOD of 1 × 10−8 mol/L. In addition, the proposed Orange II sensor was successfully applied to real food samples with satisfactory recovery.

Resonance Rayleigh Scattering Effect of Immunonanosilver Aggreagations and its Application to Rapid Determination of Trace Hg(II)

2013 ◽  
Vol 664 ◽  
pp. 749-753
Author(s):  
Li Li Xu ◽  
Zhi Liang Jiang ◽  
Ai Hui Liang
Keyword(s):  
Phosphate Buffer ◽  
Rayleigh Scattering ◽  
Sodium Citrate ◽  
Rapid Determination ◽  
Phosphate Buffer Solution ◽  
Resonance Rayleigh Scattering ◽  
Buffer Solution ◽  
Scattering Effect ◽  
Large Particles

Using PEG-10000 and sodium citrate as stabilizer, and NaBH4 as reducer, a stable nanosilvers (AgNPs) sol was prepared. In pH 6.6 phosphate buffer solution containing NaCl, the AgNPs were aggregated to large particles, which lead to resonance Rayleigh scattering (RRS) peak at 350 nm enhancement. Upon addition of cysteine, the peak decreased. The decreased value ΔI is linear to cysteine concentration in the range of 5-60×10-8 mol/L. Thus, a new RRS method was proposed for detection of cysteine.

scholarly journals Online Coupling of Lab-on-Valve Format to Amperometry Based on Polyvinylpyrrolidone-Doped Carbon Paste Electrode and Its Application to the Analysis of Morin

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Yang Wang ◽  
Guojun Yao ◽  
Jie Tang ◽  
Chun Yang ◽  
Qin Xu ◽  
...  
Keyword(s):  
Carbon Paste Electrode ◽  
Supporting Electrolyte ◽  
Phosphate Buffer Solution ◽  
Current Response ◽  
Oxidation Peak ◽  
Carbon Paste ◽  
Buffer Solution ◽  
Electrochemical Behaviors ◽  
Paste Electrode

The potential capabilities and analytical performance of lab-on-valve (LOV) manifold as a front end to amperometry have been explored for the on-line determination of morin. Meanwhile, the electrochemical behaviors of morin were investigated based on polyvinylpyrrolidone- (PVP-) doped carbon paste electrode (CPE), which found that PVP can significantly improve its oxidation peak current. The excellent amperometric current response was achieved when the potential difference (ΔE) of 0.6 V was implemented in pH 6.5 phosphate buffer solution (PBS) that served as the supporting electrolyte. A well-defined oxidation peak has been obtained in studies using PVP as a modifier of CPE based on the oxidation of morin. The present work introduces the LOV technique as a useful tool for amperometric measurement, documents advantages of using programmable flow, and outlines means for miniaturization of assays on the basis of PVP modified CPE. The proposed method was applied successfully to the determination of morin in real samples, and the spiked recoveries were satisfactory.

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