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.

Evaluation of methylations and external/internal standard quantification of lipids using gas chromatography-mass spectrometry

2017 ◽  
Vol 9 (3) ◽  
pp. 419-426
Author(s):  
Yang Qin ◽  
Wang Shunhe ◽  
Chen Haiqin ◽  
Gu Zhennan ◽  
Zhang Hao ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Fatty Acid ◽  
Standard Method ◽  
Internal Standard ◽  
Gas Chromatography Mass Spectrometry ◽  
Internal Standard Method ◽  
Chromatography Mass Spectrometry ◽  
External Standard Method ◽  
External Standard

A method for rapid and efficient fatty acid derivatization was proposed and as for the quantification, it was found that the results of the external standard method were as good as those of the internal standard method.

scholarly journals Hydration Study of Synthetic Yeelimite using LXRPD and SXRPD

2014 ◽  
Vol 70 (a1) ◽  
pp. C1096-C1096
Author(s):  
Ana Cuesta ◽  
Gema Alvarez Pinazo ◽  
Angeles De la Torre ◽  
Susana Sanfélix ◽  
Inmaculada Peral ◽  
...  
Keyword(s):  
Standard Method ◽  
Internal Standard ◽  
Free Water ◽  
Ex Situ ◽  
Quantitative Phase Analysis ◽  
Internal Standard Method ◽  
X Rays ◽  
X Ray ◽  
External Standard Method

XRPD is a powerful tool for material characterization in general, and for in-situ studies of chemical processes in particular. The use of an intense X-ray source, .i.e. synchrotron X-rays, coupled with fast X-ray detection permits time-resolved diffraction experiments allowing in-situ quantitative phase analysis during the early ages of cement hydration. Calcium sulfoaluminate, CSA, cements may have variable compositions, but all of them contain high amounts of ye'elimite, Ca4Al6O12SO4. Commercial CSA cements have special applications such as high strength developments at early-ages. Ye'elimite is very reactive and most of its hydration heat is released during the first eight hours of hydration . The aim of this work is to better understand the early age hydration of stoichiometric (orthorhombic) and doped (pseudo-cubic) ye'elimite samples. The parameters studied by SXRPD, LXRPD and calorimetry have been: polymorphism; water/ye'elimite ratio; and sulfate (gypsum and anhydrite) contents. This work has allowed establishing mechanisms and kinetics for hydration of ye'elimite samples by in-situ SXRPD with internal standard methodology. Moreover, pastes were also studied by ex-situ LXRPD with the external standard method, G-factor, at 2 and 7 days. Both strategies were able to quantify the amorphous contents, including free water. It is important to highlight that the results obtained at early ages, by the internal standard method, are in agreement with those obtained at later ages, G-method, showing the consistence and complementarity of both methodologies. The hydration of stoichiometric ye'elimite in the presence of gypsum is strongly hastened, when compared to the hydration process without gypsum. However, the presence of gypsum has a little effect in the hydration of doped ye'elimite. Moreover, anhydrite has also accelerated the hydration of stoichiometric ye'elimite, although its lower solubility has provoked the formation of an intermediate phase in the first hours.

scholarly journals Simultaneous Determination of Six Active Components in Oviductus Ranae via Quantitative Analysis of Multicomponents by Single Marker

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Shihan Wang ◽  
Yang Xu ◽  
Yanwei Wang ◽  
Huailei Yang ◽  
Zuying Lv ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Standard Method ◽  
Internal Standard ◽  
Active Components ◽  
External Standard Method ◽  
Significant Difference ◽  
External Standard ◽  
Single Marker ◽  
Quantitative Results ◽  
Oviductus Ranae

A method, quantitative analysis of multicomponents by single marker (QAMS), was established in this article to investigate the quality control of a traditional Chinese medicine, Oviductus Ranae. 7-Hydroxycholesterol, 7-ketocholesterol, 4-cholesten-3-one, stigmasterol, 7-dehydrocholesterol, and cholesterol were selected as the indexes of quality evaluation of Oviductus Rana. The determination was achieved on an Agilent HC-C18 column (4.6 mm × 250 mm, 5 μm) using methanol with water (87 : 13 v/v) as mobile phase at the flow rate of 2.0 mL/min. Cholesterol was used as an internal standard to determine the relative correction factors between cholesterol and other steroidal constituents in Oviductus Ranae. The contents of those steroidal constituents were calculated at the same time. To evaluate the QAMS method, an external standard method was used to determine the contents of six steroidal constituents. No significant difference was observed when comparing the quantitative results of QAMS with the results of external standard method. The proposed QAMS method was proved to be accurate and feasible based on methodological experiments. QAMS provided a simple, efficient, economical, and accurate way to control the quality of Oviductus Ranae.

Innovative Internal Standard Method Quality Control of Alcohol Products. Comparative analysis

2021 ◽  
pp. 13-18
Author(s):  
Сергей Вячеславович Черепица ◽  
Светлана Николаевна Сытова ◽  
Антон Николаевич Коваленко ◽  
Лидия Николаевна Соболенко ◽  
Евгений Дмитриевич Шевченко ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Volatile Compounds ◽  
Standard Method ◽  
Internal Standard ◽  
Alcoholic Beverages ◽  
Quality And Safety ◽  
Labor Costs ◽  
Quantitative Content ◽  
External Standard Method ◽  
External Standard

Для обеспечения надлежащего качества и безопасности алкогольной продукции перед поставкой ее потребителям выполняется определение количественного содержания летучих компонентов. Данный контроль выполняют на газовых хроматографах. Количественный расчет значений концентраций выполняют по методу внешнего стандарта и по методу внутреннего стандарта. Метод внешнего стандарта используется в межгосударственных стандартах: ГОСТ 30536-2013, ГОСТ 31684-2012, ГОСТ 33833-2016, ГОСТ 33834-2016, ГОСТ 33408-2015, ГОСТ 31684-2012 и в государственных стандартах ГОСТ Р 52363-2005 и СТБ ГОСТ Р 51698-2001. С целью достижения высокой достоверности получаемых данных при контроле качества и безопасности алкогольной продукции, уменьшения материальных, финансовых и трудовых затрат предложен инновационный метод, заключающийся в использовании этилового спирта, содержащегося в испытуемом образце, в качестве внутреннего стандарта. Эффективность метода продемонстрирована на примере сравнительного анализа результатов определения количественного содержания летучих компонентов в широком спектре алкогольной продукции, выполненного по используемому в настоящее время методу внешнего стандарта и по предложенному методу. Показано, что для валидации метода и последующего его внедрения в практику испытательных лабораторий не требуется каких-либо дополнительных материальных, финансовых или трудовых затрат. To ensure the proper quality and safety of alcoholic beverages, the quantitative content of volatile compounds is determined before delivery to consumers. This control is performed on gas chromatographs. The quantitative calculation of the concentration values is carried by external and internal standard methods. The external standard method is used in standards: GOST 30536-2013, GOST 31684-2012, GOST 33833-2016, GOST 33834-2016, GOST 33408-2015, GOST 31684-2012 and in state standards GOST R 52363-2005 and STB GOST R 51698-2001. In order to achieve high reliability of the data obtained when controlling the quality and safety of alcoholic beverages, and to reduce material, financial and labor costs, an innovative method is proposed. This method is based on using ethyl alcohol, contained in the test sample, as an internal standard. The effectiveness of the method is demonstrated by the example of a comparative analysis of the results of determining the quantitative content of volatile compounds in a wide range of alcoholic beverages, performed according to the currently used external standard method and according to the proposed method. It is shown that for validation the method and its subsequent implementation into the practice of testing laboratories does not require any additional material, financial or labor costs.

Accurate fully automated powder diffraction data using zero-background sample holders

1994 ◽  
Vol 9 (3) ◽  
pp. 172-179 ◽  
Author(s):  
S. T. Misture ◽  
L. R. Chatfield ◽  
R. L. Snyder
Keyword(s):  
Standard Method ◽  
Internal Standard ◽  
Standard Technique ◽  
Calibration Method ◽  
Internal Standard Method ◽  
Absorption Coefficients ◽  
Calibration Methods ◽  
Wide Range ◽  
External Standard ◽  
Standard Calibration

An increasingly frequent used sample holder, the zero-background holder (ZBH), is evaluated for use in external standard calibration of powder patterns. The effectiveness of the ZBH calibration method is determined by comparison to the conventional internal- and external-standard calibration techniques. The three calibration methods are compared using the results of lattice parameter refinements of test powders, using Si as the standard. Several test materials were used in the evaluation which cover a wide range of absorption coefficients so sample transparency effects can be distinguished from sample displacement effects. Results of the calibrations clearly indicate that the ZBH method gives precision and accuracy comparable to the internal-standard method, and significantly better than the external-standard technique. In addition, the ZBH method yields substantially better results than the internal-standard method for materials with low absorption coefficients. Low-angle calibrations are also made on a ZBH using a proposed standard, silver behenate, which has peaks from 1.5° to 20° 2θ. These calibrations have shown that if care is not taken to establish a monolayer of powder on the ZBH crystal, significant errors in refined lattice parameters will result.

Determination of alcohols in mixtures by 19F NMR spectroscopy using hexefluoroacetone reagent

1982 ◽  
Vol 47 (7) ◽  
pp. 1973-1978 ◽  
Author(s):  
Jiří Karhan ◽  
Zbyněk Ksandr ◽  
Jiřina Vlková ◽  
Věra Špatná
Keyword(s):  
Standard Deviation ◽  
Nmr Spectroscopy ◽  
Standard Method ◽  
Internal Standard ◽  
Internal Standard Method ◽  
Concentration Region ◽  
Experimental Conditions ◽  
Curve Method ◽  
Sample Preparation Procedure

The determination of alcohols by 19F NMR spectroscopy making use of their reaction with hexafluoroacetone giving rise to hemiacetals was studied on butanols. The calibration curve method and the internal standard method were used and the results were mutually compared. The effects of some experimental conditions, viz. the sample preparation procedure, concentration, spectrometer setting, and electronic integration, were investigated; the conditions, particularly the concentrations, proved to have a statistically significant effect on the results of determination. For the internal standard method, the standard deviation was 0.061 in the concentration region 0.032-0.74 mol l-1. The method was applied to a determination of alcohols in the distillation residue from an oxo synthesis.

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