scholarly journals Does Ordinary Portland Cement contain amorphous phase? A quantitative study using an external standard method

2011 ◽  
Vol 26 (1) ◽  
pp. 31-38 ◽  
Author(s):  
D. Jansen ◽  
Ch. Stabler ◽  
F. Goetz-Neunhoeffer ◽  
S. Dittrich ◽  
J. Neubauer
Keyword(s):  
Portland Cement ◽  
Standard Method ◽  
Ordinary Portland Cement ◽  
Atomic Displacement ◽  
Amorphous Content ◽  
External Standard Method ◽  
External Standard ◽  
Refinement Procedure ◽  
Atomic Displacement Parameters ◽  
The Impact

A suitable external standard method which was first described by O’Connor and Raven (1988) (“Application of the Rietveld refinement procedure in assaying powdered mixtures,” Powder Diffr. 3, 2–6) was used to determine the quantitative phase composition of a commonly used Ordinary Portland Cement (OPC). The method was also applied in order to determine amorphous contents in OPC. Also investigated were the impact of atomic displacement parameters and the microstrain on the calculated amorphous content. The investigations yielded evidence that said parameters do indeed exert an influence on the calculated amorphous content. On the basis of the data produced we can conclude that the method used is entirely to be recommended for the examination of OPC. No significant amorphous content could be proven in the OPC used.

Detection of 9α-OH-AD Prepared by Biotransformation

2013 ◽  
Vol 821-822 ◽  
pp. 1005-1008
Author(s):  
Li Min Ma ◽  
Li Cui ◽  
Yu Hang Zhao
Keyword(s):  
Quality Control ◽  
Correlation Coefficient ◽  
Flow Rate ◽  
Standard Method ◽  
Mobile Phase ◽  
Average Recovery ◽  
Rp Hplc ◽  
External Standard Method ◽  
External Standard

Detection of 9а-OH-AD prepared by biotransformation by RP-HPLC directly was studied.The detection is performed on a Kromasil 100-5C18(4.6×250mm) column, using methanol:water(7:3,v/v)as mobile phase,0.8mL•min-1flow rate and external standard method,deteced at 242nm.There is a good line correlaction between peak and content in range of 0.01-0.20g/L,the correlation coefficient is 0.9942,the average recovery is 99.09% with a relative stand deviation of 0.89%(n=5).The method is simple,stable,accurate and reliable for quality control of 9а-OH-AD.

scholarly journals Mass Spectral Characterization and UPLC Quantitation of 3-Deoxyanthocyanidins in Sorghum bicolor Varietals

2018 ◽  
Vol 101 (1) ◽  
pp. 242-248
Author(s):  
Nathan P Stern ◽  
Jatinder Rana ◽  
Amitabh Chandra ◽  
John Balles
Keyword(s):  
Sorghum Bicolor ◽  
Dietary Supplement ◽  
High Throughput ◽  
Standard Method ◽  
High Throughput Screening ◽  
Polyphenolic Compounds ◽  
Mass Spectral ◽  
External Standard Method ◽  
External Standard ◽  
Method Accuracy

Abstract A quantitative ultra-performance LC (UPLC) method was developed and validated to successfully separate, identify, and quantitate the major polyphenolic compounds present in different varieties of sorghum (Sorghum bicolor) feedstock. The method was linear from 3.2 to 320 ppm, with an r2 of 0.99999 when using luteolinidin chloride as the external standard. Method accuracy was determined to be 99.5%, and precision of replicate preparations was less than 1% RSD. Characterization by UPLC-MS determined that the predominant polyphenolic components of the sorghum varietals were 3-deoxyanthocyanidins (3-DXAs). High-throughput screening for 3-DXA identified four unique classes within the sorghum varieties. Certain feedstock varieties have been found to have a high potential to not only be plant-based colorants, but also provide significant amounts of bioactive 3-DXAs, making them of unique interest to the dietary supplement industry.

scholarly journals Simultaneous Determination of Four Ingredients in Plantago Depressa by Single Marker

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Yang Xu ◽  
Yuejie Wang ◽  
Shengnan Bi ◽  
Yanxue Jia ◽  
Huiwei Bao
Keyword(s):  
Simultaneous Determination ◽  
Standard Method ◽  
Protocatechuic Acid ◽  
Correction Factors ◽  
Active Components ◽  
Relative Correction ◽  
External Standard Method ◽  
External Standard ◽  
Single Marker

Objective. To establish a quantitative analysis of multicomponents by single marker (QAMS) method for the simultaneous determination of 4 active components such as protocatechuic acid, catechin, quercetin, and luteolin in Plantago depressa. Method. 4 active components in Plantago depressa were studied. Quercetin was used as an internal reference to establish the relative correction factors among protocatechuic acid, catechin, and luteolin and calculate the contents of each component; the results were compared with those measured by the external standard method. Results. 4 components showed a good linear relationship in their respective concentration ranges (r > 0.9995). The relative correction factors (fs/k) of protocatechuic acid, catechin, and luteolin were 1.1992, 0.8613, and 1.6069, respectively. The method had good durability. The contents of protocatechuic acid, catechin, and luteolin calculated by QAMS were not significantly different from those measured by the external standard method. Conclusion. QAMS can be used to determine the content of 4 components in Plantago depressa at the same time, and the method is simple, accurate, and can be used for quality control.

A study to assess the performance of an “X-ray powder diffraction with Rietveld” approach for measuring the crystalline and amorphous components of inhalable dust collected on aerosol sampling filters

2019 ◽  
Vol 34 (3) ◽  
pp. 251-259 ◽  
Author(s):  
P. Stacey
Keyword(s):  
Rietveld Method ◽  
Internal Standard ◽  
Relative Difference ◽  
Wood Dust ◽  
Aerosol Sampling ◽  
Amorphous Content ◽  
Quartz Fibre ◽  
External Standard Method ◽  
External Standard ◽  
Inhalable Dust

This work was undertaken in preparation for a survey to assess the exposure of carpenters to hazardous dust working in construction. Inhalable dust, in this industry, was expected to contain both crystalline mineral and amorphous phases (wood dust). The Rietveld method was applied to provide a simultaneous multicomponent analysis. To assess its performance, mixtures of aerosolised calcite, gypsum, quartz, kaolinite, and wood dust were collected onto quartz fibre filters (n = 41) using the Button inhalable sampler. Results obtained using Rietveld were compared with loaded mass and those from external standard calibrations. The measured content of a component in 14 samples was used as an internal standard by Rietveld to determine amorphous content (wood). The performance of the Rietveld and external standard methods was similar. The 95% confidence interval for the absolute differences between the two methods was 15%. Only one relative difference of more than 15% had a mass loading >0.5 mg. An approach for assessing the limits of detection with relative intensity ratios was applied and gave comparable values with the usual method using calibration coefficients from the external standard method. Rietveld is therefore a potentially useful multicomponent method for the measurement of dust aerosol to help better understand workers' exposures.

scholarly journals Preliminary Studies on Liquiritin, Deoxyschizandrin, and Tanshinone II A as Potential Anti-Neurodegenerative Disease Agent: Determination by Reverse-Phase Liquid Chromatography in Tianwang Buxin Pills

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Dan Xu ◽  
Sicen Wang ◽  
Xiaofang Hou ◽  
Changshan Sun
Keyword(s):  
Phosphoric Acid ◽  
Neurodegenerative Disease ◽  
Standard Method ◽  
Internal Standard ◽  
Acetonitrile Solution ◽  
Array Detector ◽  
Internal Standard Method ◽  
Tanshinone Ii A ◽  
External Standard Method ◽  
External Standard

Tianwang Buxin pill (TWBXP) is an ancient Chinese classic prescription. Liquiritin, deoxyschizandrin, and tanshinone II A are three bioactive components in TWBXP, which have been proven to be closely related to the therapy effect of neurodegenerative disease. Their contents are very low in TWBXP. In this study, we used a diode array detector (DAD) to perform a full wavelength scanning in order to choose a most suitable detection wavelength to establish an HPLC method for the simultaneous determination of these three components in TWBXP. Various chromatographic conditions were investigated to verify its applicability. Finally, a Kromasil C18 column (250 × 4.6 mm, 5 μm) thermostated at 30°C, mobile phase as 0.2% phosphoric acid solution (eluent A), and 0.1% phosphoric acid-acetonitrile solution (eluent B) were used. Both external standard method and internal standard method were used for quantification. The results showed that both methods were simple and convenient in operation without special pretreatment and exhibits excellent precision, repeatability (RSD < 3.0%), good linearity (R2 > 0.9990), and good recoveries (recovery value between 95% and 105%). Because of the low contents in samples, the internal standard method provided a better accurate result than the external standard method. The stability results showed the sample became stable within 24 hours at room temperature. The method provides a convenient and effective way for the quality control of TWBXP, and it can help the research about AD in the future.

An external standard method for angular calibration of powder diffractometers

2000 ◽  
Vol 15 (3) ◽  
pp. 173-174
Author(s):  
Wu Wanguo ◽  
Ruan Yuzhong
Keyword(s):  
Standard Method ◽  
External Standard Method ◽  
The Us ◽  
External Standard

An external standard method using mica for angular calibration of powder diffractometers is described. This is useful especially when standard referee materials certified by the US National Institute of Standards and Technology are not accessible.

scholarly journals Improvement of accuracy in quantitative TXRF analysis of soil sample by applying external standard method

2016 ◽  
Vol 29 (6) ◽  
pp. 261-268
Author(s):  
Jinkyu Park ◽  
Ranhee Park ◽  
Sun Ho Han ◽  
Sang Ho Lim ◽  
Chi Gyu Lee ◽  
...  
Keyword(s):  
Soil Sample ◽  
Standard Method ◽  
External Standard Method ◽  
External Standard
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