共查询到20条相似文献,搜索用时 120 毫秒
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以国家一级焦炭标准物质(GBW 11106h)为例,对焦炭标准物质的测量不确定度进行评定。分析了不确定度的主要来源,对各不确定度分量进行了评定。焦炭标准物质的全硫、灰分、挥发分、磷含量的扩展不确定度分别为0.02%、0.17%、0.05%、0.001%,热值的扩展不确定度为0.14MJ/kg。 相似文献
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建立了食用合成色素诱惑红溶液标准物质的制备和定值方法,研制了100 mg/L的诱惑红溶液标准物质。采用制备液相色谱对筛选的市售原料纯化,得到纯度大于99%的诱惑红纯品;通过核磁共振(1H NMR谱)和液相色谱-质谱(HPLC-LTQ/MS)准确定性分析后,利用高效液相色谱法(HPLC)对诱惑红纯物质进行纯度定值。以0.1 mol/L乙酸铵和甲醇为流动相进行等度洗脱,采用Intersil ODS-C18(250 mm×4.6 mm,5μm)进行分离,检测波长240 nm。为保证纯度测量的准确性,采用多家联合定值对诱惑红的纯度进行定值,诱惑红纯物质的定值纯度为99.61%(λ=240 nm)。诱惑红溶液标准物质经重量-容量法配制后,进行均匀性和稳定性实验,浓度赋值后进行不确定度评定,诱惑红溶液的量值为100 mg/L,扩展相对不确定度为1.0%(k=2)。该溶液标准物质已批准为国家级标准物质,可为相关部门提供检测标准。 相似文献
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简述电化学电极气体氧分析器的计量检定方法及过程。给出了检定过程中测量误差的数学模型及电化学电极气体氧分析器计量标准不确定度的来源,并对各不确定度分量进行了评定。电化学电极气体氧分析器计量标准的扩展不确定度小于5%。 相似文献
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For the determination of the calorific value of gases, a mass determination system for the gas burnt in the calorimeter was developed. Contrary to classical methods, which weigh the gas bottle offline, the method applied here weighs the amount of gas online and continuously. For this purpose, a commercial analytical balance with a readability of 10 µg across the entire weighing range of 205 g was modified for use under vacuum conditions.Since the gas bottle has to be permanently connected to the calorimeter by a steel capillary, an additional force is exerted to the balance. The influence of this force is investigated and determined by a special weighing procedure.In addition, an automatic calibration technique must be developed to ensure the traceability of the results to the national standard of mass. This allows an uncertainty analysis according to the Guide to the Expression of Uncertainty in Measurement (GUM) to be performed.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
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The present study summarizes the measurement uncertainty estimations carried out in Nestlé Research Center since 2002. These estimations cover a wide range of analyses of commercial and regulatory interests. In a first part, this study shows that method validation data (repeatability, trueness and intermediate reproducibility) can be used to provide a good estimation of measurement uncertainty.In a second part, measurement uncertainty is compared to collaborative trials data. These data can be used for measurement uncertainty estimation as far as the in-house validation performances are comparable to the method validation performances obtained in the collaborative trial.Based on these two main observations, the aim of this study is to easily estimate the measurement uncertainty using validation data. 相似文献
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A rule-based method for evaluating the Sachs formula is introduced. For simple molecules, such as linear chains and monocycles, the Sachs formula can be evaluated by directly using the rules. For complex molecular systems, the Sachs formula can be evaluated by first breaking up the molecule into constituent pieces of sufficient simplicity so that data for them are available in the data base and then constructing the molecule from the known data by adding all pieces together, one at a time, via a series of binary rules. The method changes the way of evaluating the Sachs formula from a trial-and-error-type numerical search to a purely algebraic manipulation and thus tremendously reduces the computing times. © 1997 John Wiley & Sons, Inc. Int J Quant Chem 65 : 19–36, 1997 相似文献
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Motozumi Ando Masaki Hirabatake Hisateru Yasui Shoji Fukushima Nobuyuki Sugioka Tohru Hashida 《Biomedical chromatography : BMC》2020,34(3):e4776
Mitotane is a key drug for the treatment of adrenal cortical carcinoma. Due to its narrow therapeutic window, 14–20 μg/mL, monitoring its concentration is crucially important. In this study, a simplified method for measuring mitotane in plasma using gas chromatography-electron ionization-mass spectrometry (GC-EI-MS) was developed. Through deproteination and liquid–liquid extraction, mitotane and an internal standard (IS) were extracted from plasma samples. GC-EI-MS yielded retention times of 8.2 and 8.7 min, for mitotane and the IS, respectively, with a total run time of 12 min. Selectivity and intra-/inter-batch accuracy and precision analyses provided a lower limit of quantification of 0.25 μg/mL, and a calibration curve between 0.25 and 40 μg/mL had good linearity (coefficient of determination = 0.992). The matrix effect factor and percent recovery of the method had good precision. Additionally, long-term sample stability was observed below 4°C. In a clinical setting, mitotane levels in plasma from an adrenal cortical carcinoma patient were within calibration range. Therefore, this simplified method can be applied to routine therapeutic drug monitoring of mitotane, which may contribute to improved treatment of adrenal cortical carcinoma. 相似文献
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N. A. Malakhova A. A. Mysik S. Yu. Saraeva N. Yu. Stozhko M. A. Uimin A. E. Ermakov Kh. Z. Brainina 《Journal of Analytical Chemistry》2010,65(6):640-647
A procedure is developed for the immobilization of bismuth nanoparticles prepared by the method of gas condensation on inert
supports manufactured by the screen printing method using carbon-containing inks. The electrochemical behavior of the immobilized
bismuth nanoparticles is investigated, and the conditions of their electrochemical activation are found. The composition of
the modifying suspension “bismuth nanoparticles-liquid” is optimized. The elaborated thick-film carbon-containing electrode
modified by bismuth nanoparticles is shown to be similar in its analytical parameters to the commercially available thick-film
carbon-containing electrode premodified by calomel, and substantially exceeds carbon-containing electrodes with electrolytically
deposited bismuth films in its properties. The limits of detection for heavy metals by stripping voltammetry are as follows
(μg/L): 0.38 for Zn(II), 0.40 for Cd(II), and 0.55 for Pb(II) at the preconcentration time 180 s. 相似文献
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Summary The gas Chromatographic procedure can be used for the rapid and accurate determination of small amounts of nicotine in biological material. Application of the method proved successful in the determination of the disappearance of nicotine from mouse skin following the application of this alkaloid directly to the skin surface. A plot ofg of nicotine per mg DNA or protein of mouse skin versus the time in hr following the application of nicotine showed that the biological half-life of nicotine in mouse skin over the first 6 hr is 1.2 hr.
Ein vereinfachtes Verfahren zur gas-chromatographischen Bestimmung von Nikotin. Anwendung auf die Haut von Mäusen
Zusammenfassung Das beschriebene Verfahren kann zur raschen und genauen Bestimmung geringer Mengen Nikotin in biologischem Material dienen. Das Verschwinden des Nikotins nach dessen Applikation auf die Hautoberfläche von Mäusen wurde damit untersucht. Trägt mang Nikotin/mg DNS der Mäusehaut gegen die Zeit nach Applikation des Nikotins auf, so zeigt sich, daß die biologische Halbzeit des Nikotins in der Mäusehaut innerhalb der ersten 6 Stunden 1,2 Stunden beträgt.相似文献
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Novel abrasion resistant coating materials prepared by the sol-gel method have been developed and applied on the polymeric substrates bisphenol-A polycarbonate and diallyl diglycol carbonate resin (CR-39). These coatings are inorganic/organic hybrid network materials synthesized from 3-isocyanatopropyltriethoxysilane functionalized organics and metal alkoxide. The organic components are 3,3-iminobispropylamine (IMPA), resorcinol (RSOL), diethylenetriamine (DETA), poly(ethyleneimine) (PEI), glycerol and a series of diols. The metal alkoxides are tetraethoxysilane (TEOS) and tetramethoxysilane (TMOS). These materials are spin coated onto bisphenol-A polycarbonate and CR-39 sheets and thermally cured to obtain a transparent coating of a few microns in thickness. Following the curing, the abrasion resistance is measured and compared with an uncoated control. It was found that the abrasion resistance of inorganic/organic hybrid coatings in the neat form or containing metal alkoxide can be very effective to improve the abrasion resistance of polymeric substrates. The adhesion tests show that the adhesion between coating and substrate can be greatly improved by treating the polymeric substrate surface with a primer solution of isopropanol containing 3-aminopropyltriethoxysilane (3-APS). The interaction between 3-APS and the polycarbonate surface was investigated by a molecular dynamics simulation. The results strongly suggest that the hydrogen bonding between the amino group of the 3-APS and ester group in the polycarbonate backbone are sufficiently strong to influence the orientation of the primer molecules. The abrasion resistance of these new coating systems is discussed in light of the structure of the organic components. All of these results show that these coating materials have excellent abrasion resistance and have potential applications as coating materials for lenses and other polymeric products. 相似文献
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Yoshimori T 《Talanta》1975,22(10-11):827-835
A review is given of the methods of drying standard reference materials, and handling them after drying. The status of the Faraday as an international reference standard for titrimetric analysis is also discussed. 相似文献
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K. Masumoto 《Journal of Radioanalytical and Nuclear Chemistry》1996,203(1):37-46
The internal standard method coupled with the standard addition method has been applied to the analysis of environmental materials, such as urban particulate matter, vehicle exhaust particulates and coal fly ash by photon activation. High-resolution gamma-ray spectrometry makes possible to use multi-internal standard gamma-rays, in order to crosscheck the analytical results obtained from each internal standard. It was ascertained that this method can provide not only accurate analytical results but also the information of homogeneity of samples, correlation of elements in the sample, loss or contamination in the preparation process. 相似文献
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《Polymer Testing》1987,7(5):355-363
A method which evaluates the critical J-integral value (Jc) by utilizing the locus of crack initiation points on load-displacement records is presented. This method partitions the fracture energy along the locus line based on an energy rate interpretation. The shape of the locus line depends on both the material and the configuration of the specimen. Since the fracture energy can be partitioned even along a nonlinear locus line, the method is also suitable for highly deformable materials, which usually exhibit a nonlinear locus line. In order to validate this point, a thermoplastic rubber was used for experimental study. The experimental results show that Jc can be evaluated by this method without restricting the ratio of the initial crack length to the specimen width (a/w) or the specimen length provided that the locus line can be located on the load-displacement record. 相似文献