scholarly journals Development of an HPLC method with relative molar sensitivity based on 1H-qNMR to determine acteoside and pedaliin in dried sesame leaf powders and processed foods

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243175
Author(s):  
Takashi Ohtsuki ◽  
Kiyoaki Matsuoka ◽  
Yushiro Fuji ◽  
Yuzo Nishizaki ◽  
Naoko Masumoto ◽  
...  

A high-performance liquid chromatography (HPLC) method with relative molar sensitivity (RMS) based on 1H quantitative NMR spectroscopy (1H-qNMR) has been developed for food ingredients such as acteoside (verbascoside) and pedaliin (pedalitin-6-O-glucoside) without requiring authentic and identical standards as the reliable analytical methods. This method is used methyl 4-hydroxybenzoate (MHB) as an alternative reference standard. Each RMS is also calculated from the ratio of each analyte's molar absorption coefficient to that of MHB after correcting the purities of the analytes and reference standard by 1H-qNMR. Therefore, this method can quantify several analytes with metrological traceability to the International System of Units (SI) using the RMS and one alternative reference standard. In this study, the content of acteoside and pedaliin in several samples, such as dried sesame leaf powders and commercially processed foods, can be determined by the proposed RMS method and demonstrated in good agreement that obtained by a conventional method. Moreover, the proposed method yields analytical data with SI-traceability without the need for an authentic and identical analyte standard. Thus, the proposed RMS method is a useful and practical tool for determining acteoside and pedaliin in terms of the accuracy of quantitative values, the routine analysis, and the cost of reagents.

2018 ◽  
Author(s):  
Rainer Feistel

Abstract. In the terrestrial climate system, water is a key player in the form of its different ambient phases of ice, liquid and vapour, admixed with sea salt in the ocean and with dry air in the atmosphere. For proper balances of climatic energy and entropy fluxes in models and observation, a highly accurate, consistent and comprehensive thermodynamic standard framework is requisite in geophysics and climate research. The new “Thermodynamic Equation of Seawater – 2010” (TEOS-10) constitutes such a standard for properties of water in its various manifestations in the hydrological cycle. TEOS-10 has been recommended internationally in 2009 by the Intergovernmental Oceanographic Commission (IOC) to replace the previous 1980 seawater standard, EOS-80, and in 2011 by the International Union of Geodesy and Geophysics (IUGG) “as the official description for the properties of seawater, of ice and of humid air”. This paper briefly reviews the development of TEOS-10, its novel axiomatic properties, new oceanographic tools it offers, and important tasks that still await solutions by ongoing research. Among the latter are new definitions and measurement standards for seawater salinity and pH, in order to establish their metrological traceability to the International System of Units (SI), for the first time after a century of widespread use. Of similar climatological relevance is the development and recommendation of a uniform standard definition of atmospheric relative humidity that is unambiguous and rigorously based on physical principles.


Foods ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 248 ◽  
Author(s):  
Minjung Song ◽  
Juhee Park ◽  
Jihyun Lee ◽  
Heejae Suh ◽  
Hyunjung Lee ◽  
...  

An analytical method to measure solubilized orthophosphate ions (HPO42− and PO43− ) from the water-insoluble food additives calcium phosphate dibasic (DCP) and calcium phosphate tribasic (TCP) in processed foods was optimized by comparing ion chromatography (IC) coupled with DS6 conductivity detector (Cond.) and high-performance liquid chromatography (HPLC) with Evaporative light scattering detector (ELSD) methods. The ion-pairing HPLC method could analyze calcium and phosphate ions successively. However, this method exhibited low reproducibility after approximately 48 hours of measurements. The IC method was established as an effective method of measuring orthophosphate ions with high reproducibility using distilled water and KOH solution as the mobile phase with a Dionex column. Matrix-based limit of detections (LOD) and limit of quantifications (LOQ) for snacks and cereals were estimated in the range of 0.01–0.91 µg/mL and 0.21–2.74 µg/mL, respectively. In inter-day and intra-day tests, the calculated precision (%RSD) and accuracy (recovery %) ranged from 0.5% to 6.6% and 82% to 117%, respectively, in both food samples. The levels of DCP or TCP could be analyzed in various positive food samples, and the developed IC method demonstrated good applicability in the analysis of DCP and TCP in collected processed foods.


2019 ◽  
Vol 15 (3) ◽  
pp. 277-293 ◽  
Author(s):  
Sevinc Kurbanoglu ◽  
Ozer Karsavurdan ◽  
Sibel A. Ozkan

Introduction: Ultra-Performance Liquid Chromatographic (UPLC) method enables analyst to establish an analysis at higher pressure than High Performance Liquid Chromatographic (HPLC) method towards liquid chromatographic methods. UPLC method provides the opportunity to study a higher pressure compared to HPLC, and therefore smaller column in terms of particle size and internal diameter are generally used in drug analysis. The UPLC method has attracted gradually due to its advantages such as short analysis time, the small amount of waste reagents and the significant savings in the cost of their destruction process. In this review, the recent selected studies related to the UPLC method and its method validation are summarized. The drug analyses and the results of the studies which were investigated by UPLC method, with certain parameters from literature are presented. Background: Quantitative determination of drug active substances by High-Performance Liquid Chromatography (HPLC) from Liquid Chromatography (LC) methods has been carried out since the 1970's with the use of standard analytical LC methods. In today's conditions, rapid and very fast even ultra-fast, flow rates are achieved compared to conventional HPLC due to shortening analysis times, increasing method efficiency and resolution, reducing sample volume (and hence injection volume), reducing waste mobile phase. Using smaller particles, the speed and peak capacity are expanding to new limit and this technology is named as Ultra Performance Liquid Chromatography. In recent years, as a general trend in liquid chromatography, ultra-performance liquid chromatography has taken the place of HPLC methods. The time of analysis was for several minutes, now with a total analysis time of around 1-2 minutes. The benefits of transferring HPLC to UPLC are much better understood when considering the thousands of analyzes performed for each active substance, in order to reduce the cost of analytical laboratories where relevant analysis of drug active substances are performed without lowering the cost of research and development activities. Methods: The German Chemist Friedrich Ferdinand Runge, proposed the use of reactive impregnated filter paper for the identification of dyestuffs in 1855 and at that time the first chromatographic method in which a liquid mobile phase was used, was reviewed. Christian Friedrich Chönbein, who reported that the substances were dragged at different speeds in the filter paper due to capillary effect, was followed by the Russian botanist Mikhail S. Tswet, who planted studies on color pigment in 1906. Tswet observes the color separations of many plant pigments, such as chlorophyll and xanthophyll when he passes the plant pigment extract isolated from plant through the powder CaCO3 that he filled in the glass column. This method based on color separation gives the name of "chromatographie" chromatography by using the words "chroma" meaning "Latin" and "graphein" meaning writing. Results and Conclusion: Because the UPLC method can be run smoothly at higher pressures than the HPLC method, it offers the possibility of analyzing using much smaller column sizes and column diameters. Moreover, UPLC method has advantages, such as short analysis time, the small amount of waste reagents and the significant savings in the cost of their destruction process. The use of the UPLC method especially analyses in biological samples such as human plasma, brain sample, rat plasma, etc. increasingly time-consuming due to the fact that the analysis time is very short compared to the HPLC, because of the small amount of waste analytes and the considerable savings in their cost.


2016 ◽  
Vol 4 (2) ◽  
pp. 81-83
Author(s):  
Akiharu Hioki ◽  

Metrological traceability to an international reference, the International System of Units (SI) if possible, is important for the reliability of measurements. The international traceability system under the Metre Convention is briefly introduced. The simplest way to secure metrological traceability in chemical analyses is to utilise certified reference materials (CRMs) for calibration and validation. Finally, as examples of CRMs, NMIJ ones are described.


Ocean Science ◽  
2018 ◽  
Vol 14 (3) ◽  
pp. 471-502 ◽  
Author(s):  
Rainer Feistel

Abstract. In the terrestrial climate system, water is a key player in the form of its different ambient phases of ice, liquid and vapour, admixed with sea salt in the ocean and with dry air in the atmosphere. For proper balances of climatic energy and entropy fluxes in models and observations, a highly accurate, consistent and comprehensive thermodynamic standard framework is requisite in geophysics and climate research. The new Thermodynamic Equation of Seawater – 2010 (TEOS-10) constitutes such a standard for properties of water in its various manifestations in the hydrological cycle. TEOS-10 was recommended internationally in 2009 by the Intergovernmental Oceanographic Commission (IOC) to replace the previous 1980 seawater standard, EOS-80, and in 2011 by the International Union of Geodesy and Geophysics (IUGG) as the official description for the properties of seawater, of ice and of humid air. This paper briefly reviews the development of TEOS-10, its novel axiomatic properties, the new oceanographic tools it offers and the important tasks that still await solutions by ongoing research. Among the latter are new definitions and measurement standards for seawater salinity and pH in order to establish their metrological traceability to the International System of Units (SI) for the first time after a century of widespread use. Of similar climatological relevance is the development and recommendation of a uniform standard definition of atmospheric relative humidity that is unambiguous and rigorously based on physical principles.The leading thermodynamic properties of a fluid are determined by the relations which exist between volume, pressure, temperature, energy, and entropy … But all the relations existing between these five quantities for any substance …may be deduced from the single relation existing for that substance between volume, energy, and entropy. Josiah Willard Gibbs, 1873b


Separations ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 15
Author(s):  
Vikram Kestens ◽  
Victoria A. Coleman ◽  
Jan Herrmann ◽  
Caterina Minelli ◽  
Alex G. Shard ◽  
...  

Line-start incremental centrifugal liquid sedimentation (disc-CLS) is a powerful technique to determine particle size based on the principles of Stokes’ law. As most input quantities of the Stokes equation cannot be easily determined for typical instruments used for this method, an alternative method which depends on calibrating the sedimentation time scale with reference particles has become common practice. Unfortunately, most of these calibration materials (calibrants) come with limited information regarding their metrological reliability (e.g., lack of measurement uncertainties and traceability statements, incomplete measurand definitions). As a consequence, routine particle size results obtained by disc-CLS are mostly only traceable to the calibrant used, and effective comparisons can only be made for those results originating from measurements performed with the same types of calibrants. In this study, we discuss the concept of metrological traceability and demonstrate that particle size results obtained by disc-CLS can be traceable to the ultimate metrological reference, i.e., the unit of length in the International System of Units (SI), the meter. Using the example of two colloidal silica certified reference materials, we describe how laboratories can realize metrological traceability to the SI by simplifying complex traceability networks.


2014 ◽  
Vol 31 (5) ◽  
pp. 1104-1127 ◽  
Author(s):  
Craig J. Donlon ◽  
W. Wimmer ◽  
I. Robinson ◽  
G. Fisher ◽  
M. Ferlet ◽  
...  

AbstractQuasi-operational shipborne radiometers provide a fiducial reference measurement (FRM) for satellite validation of satellite sea surface skin temperature (SSTskin) retrievals. External reference blackbodies are required to verify the performance and to quantify the accuracy of the radiometer calibration system. They provide a link in an unbroken chain of comparisons between the shipborne radiometer and a traceable reference standard. A second-generation water bath blackbody reference radiance source has been developed for this purpose. The second generation Concerted Action for the Study of the Ocean Thermal Skin (CASOTS-II) blackbody has a 110-mm-diameter aperture cylinder-cone geometry coated with NEXTEL suede 3103 paint. Interchangeable aperture stops reduce the cavity aperture diameter and minimize stray radiation. Monte Carlo modeling techniques show the effective emissivity of the cavity to be >0.9999 (aperture < 30 mm). The cavity is immersed in a water bath that is vigorously stirred using a pump that slowly heats the water bath at a mean rate of ~0.6 K h−1. The temperature of the water bath is measured using a thermometer traceable to the International System of Units (SI) standards. The worst-case radiance temperature of the CASOTS-II blackbody system is traceable to the SI with an uncertainty of 58 mK (millikelvin). When operating under typical laboratory conditions using an aperture of 40 mm, the uncertainty is 16 mK. An intercomparison with the U.K. National Physical Laboratory Absolute Measurements of Blackbody Emitted Radiance (AMBER) reference radiometer found no significant differences within 75 mK (110-mm aperture) or 50 mK (40-mm aperture), which is the combined uncertainty of the comparison and the reference standard for SI traceability of ISAR radiometer SSTskin records used for satellite SST validation. Applications of the CASOTS-II blackbody to monitor the calibration of shipborne radiometers are described and measurement protocols are proposed.


Ocean Science ◽  
2011 ◽  
Vol 7 (1) ◽  
pp. 45-62 ◽  
Author(s):  
S. Seitz ◽  
R. Feistel ◽  
D. G. Wright ◽  
S. Weinreben ◽  
P. Spitzer ◽  
...  

Abstract. Consistency of observed oceanographic salinity data is discussed with respect to contemporary metrological concepts. The claimed small uncertainty of salinity measurement results traceable to the conductivity ratio of a certified IAPSO Standard Seawater reference is not metrologically justified if results are compared on climatic time scales. This applies in particular to Practical Salinity SP, Reference Salinity SR, and the latest estimates of Absolute Salinity using the TEOS-10 formalism. On climate time scales an additional contribution to the uncertainty that is related to unknown property changes of the reference material must be accounted for. Moreover, when any of these measured or calculated quantity values is used to estimate Absolute Salinity of a seawater sample under investigation, another uncertainty contribution is required to quantify the accuracy of the equations relating the actually measured quantity to the Absolute Salinity. Without accounting for these additional uncertainties, such results cannot be used to estimate Absolute Salinity with respect to the International System of Units (SI), i.e. to the unit chosen for the mass fraction of dissolved material in the sample, which is "g kg−1". From a metrological point of view, such deficiencies in the calculations involving other quantities will produce SI-incompatible results. We outline how these problems can be overcome by linking salinity to primary SI measurement standards.


2017 ◽  
Vol 100 (5) ◽  
pp. 1365-1375 ◽  
Author(s):  
Romana Rigger ◽  
Alexander Rück ◽  
Christine Hellriegel ◽  
Robert Sauermoser ◽  
Fabienne Morf ◽  
...  

Abstract In recent years, quantitative NMR (qNMR) spectroscopy has become one of the most important tools for content determination of organic substances and quantitative evaluation of impurities. Using Certified Reference Materials (CRMs) as internal or external standards, the extensively used qNMR method can be applied for purity determination, including unbroken traceability to the International System of Units (SI). The implementation of qNMR toward new application fields, e.g., metabolomics, environmental analysis, and physiological pathway studies, brings along morecomplex molecules and systems, thus making use of 1H qNMR challenging. A smart workaround is possible by the use of other NMR active nuclei, namely 31P and 19F. This article presents the development of three classes of qNMR CRMs based on different NMR active nuclei (1H, 31P, and 19F), and the corresponding approaches to establish traceability to the SI through primary CRMs from the National Institute of Standards and Technology and the National Metrology Institute of Japan. These TraceCERT® qNMR CRMs are produced under ISO/IEC 17025 and ISO Guide 34 using high-performance qNMR.


2010 ◽  
Vol 7 (4) ◽  
pp. 1303-1346 ◽  
Author(s):  
S. Seitz ◽  
R. Feistel ◽  
D. G. Wright ◽  
S. Weinreben ◽  
P. Spitzer ◽  
...  

Abstract. Consistency of observed oceanographic salinity data is discussed with respect to contemporary metrological concepts. The claimed small uncertainty of salinity measurement results traceable to the conductivity ratio of a certified IAPSO Standard Seawater reference is not metrologically justified if results are compared on climatic time scales. This applies in particular to Practical Salinity SP, Reference Salinity SR, and the latest estimates of Absolute Salinity using the TEOS-10 formalism. In climate time scales an additional contribution to the uncertainty that is related to unknown property changes of the reference material must be accounted for. Moreover, when any of these measured or calculated quantity values is used to estimate Absolute Salinity of a seawater sample under investigation, another uncertainty contribution is required to quantify the accuracy of the equations relating the actually measured quantity to the Absolute Salinity. Without accounting for these additional uncertainties, such results cannot be used to estimate Absolute Salinity with respect to the International System of Units (SI), i.e. to the unit chosen for the mass fraction of dissolved material in the sample, which is "g/kg". From a metrological point of view, such deficiencies in the calculations involving other quantities will produce SI-incompatible results. We outline how these problems can be overcome by linking salinity to primary SI measurement standards.


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