scholarly journals Analyses of Total Alkaloid Extract ofCorydalis yanhusuoby Comprehensive RP × RP Liquid Chromatography with pH Difference

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Xiaodong Wei ◽  
Hongling Shen ◽  
Lijun Wang ◽  
Qingyan Meng ◽  
Wenjie Liu
Keyword(s):  
Liquid Chromatography ◽  
Total Alkaloid ◽  
Ph Value ◽  
Ammonium Hydroxide ◽  
Peak Capacity ◽  
Strong Base ◽  
Retention Factors ◽  
Ph Values ◽  
Dimension Analysis ◽  
Alternative Approach

A comprehensive two-dimensional (2D) reverse phase (RP) liquid chromatography (LC) method is developed for alkaloid analysis. This offline comprehensive 2D method is developed using different pH values. With a pH value of 10.5, most alkaloids appear in the form of neutral molecules possessing high retention factors based on their polarity, while the alkaloid polarity order is changed when the pH value decreased to 3.0. The performance of pH modulated 2D LC is demonstrated with 8 alkaloid standards which resulted in orthogonal separation. The developed method is then applied to total alkaloid separation inCorydalis yanhusuo. The first-dimension separation is carried out using methanol and water containing 1.0% ammonium hydroxide and a strong base-resistant RP column, which afforded a peak capacity of 94. The second-dimension analysis is carried out with a surface positive charge column providing a peak capacity of 205 using a mobile phase consisting of acetonitrile and water with 0.15% formic acid. 2D analyses of total alkaloid extract fromC. yanhusuoafford a total peak capacity of 9090. Sixteen compounds were tentatively identified based on their ultraviolet spectrum and MS/MS analyses. The proposed method provides an alternative approach to achieve high peak capacity for analysis of alkaloid extract.

HPLC Analysis of Oxytetracycline Residues in Honey

1986 ◽  
Vol 49 (5) ◽  
pp. 383-388 ◽  
Author(s):  
PETER SPORNS ◽  
SUET KWAN ◽  
LAWRENCE A. ROTH
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Aqueous Solutions ◽  
High Performance ◽  
Hplc Analysis ◽  
Extraction Procedure ◽  
Hplc Method ◽  
Limits Of Detection ◽  
Ph Values ◽  
Double Extraction

Oxytetracycline (OTC), also known commercially as Terramycin, was determined to be more stable in honey than in buffered aqueous solutions at similar pH values and temperatures. A rapid high performance liquid chromatography (HPLC) method was developed to detect and quantitate OTC using a 1:1 dilution (wt/wt) of honey samples in water. Using 355 nm as the wavelength of detection, amounts as low as 0.5 μg/ml could be detected in the above solution. The limits of detection were lowered considerably by a double extraction procedure.

scholarly journals Bonding of Selected Hardwoods with PVAc Adhesive

2020 ◽  
Vol 11 (1) ◽  
pp. 67
Author(s):  
Ján Iždinský ◽  
Ladislav Reinprecht ◽  
Ján Sedliačik ◽  
Jozef Kúdela ◽  
Viera Kučerová
Keyword(s):  
Adhesion Strength ◽  
Cold Water ◽  
Ph Value ◽  
Water Extract ◽  
Solid Wood ◽  
Contact Angles ◽  
Water Contact ◽  
Ph Values ◽  
Positive Tendency ◽  
The Impact

The bonding of wood with assembly adhesives is crucial for manufacturing wood composites, such as solid wood panels, glulam, furniture parts, and sport and musical instruments. This work investigates 13 hardwoods—bangkirai, beech, black locust, bubinga, ipé, iroko, maçaranduba, meranti, oak, palisander, sapelli, wengé and zebrano—and analyzes the impact of their selected structural and physical characteristics (e.g., the density, cold water extract, pH value, roughness, and wettability) on the adhesion strength with the polyvinyl acetate (PVAc) adhesive Multibond SK8. The adhesion strength of the bonded hardwoods, determined by the standard EN 205, ranged in the dry state from 9.5 MPa to 17.2 MPa, from 0.6 MPa to 2.6 MPa in the wet state, and from 8.5 MPa to 19.2 MPa in the reconditioned state. The adhesion strength in the dry state of the bonded hardwoods was not influenced by their cold water extracts, pH values, or roughness parallel with the grain. On the contrary, the adhesion strength was significantly with positive tendency influenced by their higher densities, lower roughness parameters perpendicular to the grain, and lower water contact angles.

scholarly journals Microstructure and Properties of Self-Assembly Graphene Microcapsules: Effect of the pH Value

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 587 ◽  
Author(s):  
Yan-Dong Guo ◽  
Jun-Feng Su ◽  
Ru Mu ◽  
Xin-Yu Wang ◽  
Xiao-Long Zhang ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Chemical Engineering ◽  
Ph Value ◽  
Liquid Paraffin ◽  
Energy Dispersive Spectrometer ◽  
Core Material ◽  
Microstructure And Properties ◽  
Ph Values

Graphene has attracted attention in the material field of functional microcapsules because of its excellent characteristics. The content and state of graphene in shells are critical for the properties of microcapsules, which are greatly affected by the charge adsorption equilibrium. The aim of this work was to investigate the effect of pH value on the microstructure and properties of self-assembly graphene microcapsules in regard to chemical engineering. Microcapsule samples were prepared containing liquid paraffin by a self-assembly polymerization method with graphene/organic hybrid shells. The morphology, average size and shell thickness parameters were investigated for five microcapsule samples fabricated under pH values of 3, 4, 5, 6 and 7. The existence and state of graphene in dry microcapsule samples were analyzed by using methods of scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). Fourier Transform Infrared Spectoscopy (FT-IR) and Energy Dispersive Spectrometer (EDS) were applied to analyze the graphene content in shells. These results proved that graphene had existed in shells and the pH values greatly influenced the graphene deposition on shells. It was found that the microcapsule sample fabricated under pH = 5 experienced the largest graphene deposited on shells with the help of macromolecules entanglement and electrostatic adherence. This microcapsules sample had enhanced thermal stability and larger thermal conductivity because of additional graphene in shells. Nanoindentation tests showed this sample had the capability of deforming resistance under pressure coming from the composite structure of graphene/polymer structure. Moreover, more graphene decreased the penetrability of core material out of microcapsule shells.

Study on Influence of Silicate Morphology Based on pH Value

2012 ◽  
Vol 454 ◽  
pp. 324-328
Author(s):  
Yan He ◽  
Ya Jing Liu ◽  
Yong Lin Cao ◽  
Li Xia Zhou
Keyword(s):  
Silicic Acid ◽  
Ph Value ◽  
Colorimetric Method ◽  
Absorption Spectrometry ◽  
Degree Of Polymerization ◽  
Raw Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ph Values ◽  
The Stability

Infra-red absorption spectrometry, X-ray diffraction observations and characterization tests based on silicon molybdenum colorimetric method were used to investigate the optimal pH value controlling the stability of the silicic acid form. The experiment process was done by using sodium silicate as raw material. The results showed that the solution of silicate influenced the polymerization. The active silicic acid solution with a certain degree of polymerization was obtained by controlling the pH values.

Aminoquinolines as fluorescent labels for hydrophilic interaction liquid chromatography of oligosaccharides

2012 ◽  
Vol 393 (8) ◽  
pp. 757-765 ◽  
Author(s):  
Weston B. Struwe ◽  
Pauline M. Rudd
Keyword(s):  
Liquid Chromatography ◽  
Hplc Analysis ◽  
Three Dimensional ◽  
Hydrophilic Interaction Liquid Chromatography ◽  
Peak Capacity ◽  
Fluorescent Labels ◽  
Sample Analysis ◽  
Hydrophilic Interaction ◽  
Optimal Excitation ◽  
Complex Sample

Abstract In this study, we investigated the potential of four different aminoquinoline (AQ) compounds as fluorescent labels for glycan analysis using hydrophilic interaction liquid chromatography (HILIC) and fluorescence detection (FLD). We confirmed the optimal excitation and emission wavelengths of 3-AQ and 6-AQ conjugated to glycan standards using three-dimensional fluorescent spectral scanning. The optimal excitation and emission wavelengths for 6-AQ were confirmed at λex=355 nm and λem=440 nm. We concluded that the optimal wavelengths for 3-AQ were λex=355 nm and λem=420 nm, which differed considerably from the wavelengths applied in previous reports. HILIC-FLD chromatograms using experimentally determined wavelengths were similar to 2-aminobenzamide controls, but the peak capacity and resolution differed significantly when published 3-AQ λex/em values were applied. Furthermore, we found that 5-AQ and 8-AQ labeled maltohexaose did not display any fluorescent pro\xadperties when used as a carbohydrate tag for HPLC analysis. Finally, we applied experimentally determined wavelengths to 3-AQ labeled N-glycans released from human IgG to illustrate changes in retention time as well as to demonstrate that AQ labeling is applicable to complex sample analysis via exoglycosidase sequencing.

scholarly journals Oral pH value predicts the incidence of radiotherapy related caries in nasopharyngeal carcinoma patients

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zheng Li ◽  
Qiuji Wu ◽  
Xiangyu Meng ◽  
Haijun Yu ◽  
Dazhen Jiang ◽  
...  
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Radiation Dose ◽  
Protective Factors ◽  
Green Tea ◽  
Cox Regression ◽  
Ph Value ◽  
Dynamic Monitoring ◽  
Tea Consumption ◽  
Ph Values ◽  
Kaplan Meier

AbstractRadiotherapy-related caries is a complication of radiotherapy for nasopharyngeal carcinoma; however, factors influencing the occurrence, accurate prediction of onset, and protective factors of radiotherapy-related caries remain unclear. This study analyzed risk factors, disease predictors, and protective factors for radiotherapy-related caries in nasopharyngeal carcinoma. This prospective study included 138 nasopharyngeal carcinoma patients receiving radical radiotherapy at our hospital during June 2012–December 2016 and were followed up for dental caries. Patients’ clinical data on radiotherapy were collected, dynamic monitoring was performed to assess changes in oral pH values, and a questionnaire survey was administered to collect patients’ lifestyle habits. Time-dependent cox regression trees, event-free Kaplan–Meier curve, Mann–Whitely U test were used to analysis the results. The median follow-up time was 30 (12–60) months. Radiotherapy-related caries occurred in 28 cases (20.3%). Univariate analyses showed that radiotherapy-related caries was associated with patient’s age, oral saliva pH value, green tea consumption, and radiation dose to sublingual glands, but not with the radiation dose to the parotid and submandibular glands. Multivariate analysis showed that oral saliva pH value [hazard ratio (HR) = 0.390, 95% confidence interval = 0.204–0.746] was an independent prognostic factor for radiotherapy-related caries. Patients with oral saliva pH values ≤ 5.3 in the 9th month after radiotherapy represented a significantly higher risks for radiotherapy-related caries (p < 0.001). Green tea consumption was associated with the occurrence of radiotherapy-related caries, and oral saliva pH values could predict the occurrence of radiotherapy-related caries. Limiting radiation doses to sublingual glands can reduce the occurrence of radiotherapy-related caries.

Effect of pH Value on the Synthesis of NiO Nanoparticles and Microstructure of NiO Based Composite Anode

2021 ◽  
Vol 317 ◽  
pp. 447-453
Author(s):  
Noor Hidayah Aniza Zakaria ◽  
Nafisah Osman
Keyword(s):  
Ph Value ◽  
Sol Gel ◽  
Secondary Phase ◽  
Average Diameter ◽  
Morphological Observation ◽  
Nio Nanoparticles ◽  
Composite Anode ◽  
Ph Values ◽  
Particle Size Analyzer ◽  
Nio Nps

NiO nanoparticle was synthesized by a sol-gel method with three different pH values namely pH=1, 7 and 11, and then calcined at temperature of 450 ᵒC. The influence of different pH values on the physical properties of NiO nanoparticles were investigated by a particle size analyzer (PSA), field emission scanning electron microscope (FESEM) and X-ray diffractometer (XRD). Structural analysis confirmed that a cubic structure of NiO nanoparticle was obtained without any secondary phase for NiO powders prepared with pH=1, while the peak of secondary phase (Ni) appeared for NiO powders prepared with pH= 7 and 11. Morphological observation showed that the NiO nanoparticles prepared with pH=7 and 11 tend to form more agglomerates compared to one prepared with pH=1. The average diameter of NiO nanoparticles with pH 1, 7 and 11 were approximately in the range of 19-26 nm, 21-28 nm, and 24-30 nm, respectively. NiO powder that was synthesized with pH=1 was further used to prepare composite anode of NiO Nps-BaCe0.54Zr0.36Y0.1O2.95 (BCZY) powder. Unfortunately a composite of NiO Nps-BaCeO3-BaZrO3 was obtained instead of BCZY and governed by agglomerates with size in the range of 70-300 nm.

scholarly journals Validation of high performance liquid chromatography method for determination of meloxicam loaded PEGylated nanocapsules

2015 ◽  
Vol 51 (4) ◽  
pp. 823-832 ◽  
Author(s):  
Francine Rodrigues Ianiski ◽  
Luciane Varini Laporta ◽  
Alexandre Machado Rubim ◽  
Cristiane Luchese
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Zeta Potential ◽  
Analytical Method ◽  
High Performance ◽  
Ph Value ◽  
Hplc Method ◽  
Polydispersity Index ◽  
Size Distributions ◽  
Relative Standard

abstract A method to ensure that an analytical method will produce reliable and interpretable information about the sample must first be validated, making sure that the results can be trusted and traced. In this study, we propose to validate an analytical high performance liquid chromatography (HPLC) method for the quantitation of meloxicam loaded PEGylated nanocapsules(M-PEGNC). We performed a validation study, evaluated parameters including specificity, linearity, quantification limit, detection limit, accuracy, precision and robustness. PEGylated nanocapsules were prepared by interfacial deposition of preformed polymer, and the particle size, polydispersity index, zeta potential, pH value and encapsulation efficiency were characterized. The proposed HPLC method provides selective, linear results in the range of 1.0-40.0 μg/mL; quantification and detection limits were 1.78 μg/mL and 0.59 μg/mL, respectively; relative standard deviation for repeatability was 1.35% and intermediate precision was 0.41% and 0.61% for analyst 1 and analyst 2, respectively; accuracy between 99.23 and 101.79%; robustness between 97.13 and 98.45% for the quantification of M-PEGNC. Mean particle diameters were 261 ± 13 nm and 249 ± 20 nm, polydispersity index was 0.15 ± 0.07 and 0.17 ± 0.06, pH values were 5.0 ± 0.2 and 5.2 ± 0.1, and zeta-potential values were -37.9 ± 3.2 mV e -31.8 ± 2.8 mV for M-PEGNC and placebo(B-PEGNC), respectively. In conclusion, the proposed analytical method is suitable for the quality control of M-PEGNC. Moreover, suspensions showed monomodal size distributions and low polydispersity index indicating high homogeneity of formulations with narrow size distributions, and appropriate pH and zeta potential. The extraction process was efficient for release of meloxicam from nanostructured systems.

scholarly journals Evaluation of the pH, calcium release and antibacterial activity of MTA Fillapex

2013 ◽  
Vol 42 (5) ◽  
pp. 330-335 ◽  
Author(s):  
Milton Carlos Kuga ◽  
Gisele Faria ◽  
Paulo Henrique Weckwerth ◽  
Marco Antonio Hungaro Duarte ◽  
Edson Alves De Campos ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Calcium Release ◽  
Ph Value ◽  
Diffusion Test ◽  
Evaluation Period ◽  
Ph Values ◽  
Agar Diffusion Test ◽  
Ah Plus ◽  
Endodontic Sealers ◽  
And Staphylococcus Aureus

OBJECTIVE: This study evaluated, in several analysis periods, pH and calcium release and antibacterial activity provided by MTA Fillapex sealer compared to Sealapex and AH Plus sealers. MATERIAL AND METHOD: Polyethylene tubes were filled with a sealer and immersed in distilled water. After 24 hours, 14 and 28 days, pH and calcium release by endodontic sealers were evaluated directly in water which the tubes were stored. Sealers antibacterial activity was evaluated against Enterococcus faecalis and Staphylococcus aureus by means of agar diffusion test. All data were submitted to ANOVA and Tukey tests (α=0.05). RESULT: In all periods evaluated, Sealapex had the highest pH value (p<0.05) in comparison to other sealers and MTA Fillapex provided higher pH values than AH Plus (p<0.05). In 14-days period, MTA Fillapex had greater calcium release value than Sealapex (p<0.05). In 28-days period, Sealapex provided higher calcium release than MTA Fillapex (p<0.05). In all periods, AH Plus provided lower calcium release than other sealers (p<0.05). In relation to E. faecalis, there were no differences among the sealers, in relation to antibacterial activity (p>0.05). In relation to S. aureus, Sealapex presented better antibacterial effectiveness than the MTA Fillapex and AH Plus (p<0.05), which were similar each other (p>0.05). CONCLUSION: In final evaluation period, pH values and calcium release provided by MTA Fillapex were lower than provided by Sealapex and higher than provided by AH Plus. The MTA Fillapex antimicrobial action was similar to other endodontic sealers.

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