DEVELOPMENT OF STANDARD SAMPLES OF MAGNESIUM ALLOYS VML20 AND VMD16

2021 ◽  
pp. 39-47
Author(s):  
F.N. Karachevtsev ◽  
◽  
S.G. Eroshkin ◽  
I.V. Mostayev ◽  
M.V. Akinina ◽  
...  

A technology for the manufacture and production of reference material (CRM) of the composition of magnesium alloys of the VML20 and VMD16 grades has been developed. In FSUE «VNIIOFI» tests of CRM material were carried out in order to approve their type, as well as metrological examination. Conclusions were drawn up on checking the results of CRM testing for the composition of the indicated alloys and certificates of type approval of reference materials were issued. CRM sets of the approved type of state standard samples of high-strength magnesium alloys of VML20 and VMD16 grades have a relative error of the certified values of the mass fraction of elements in the range from 0.5 to 5% (by weight) no more than 5% rel.

Author(s):  
Juliane Riedel ◽  
Sebastian Recknagel ◽  
Diana Sassenroth ◽  
Tatjana Mauch ◽  
Sabine Buttler ◽  
...  

AbstractZearalenone (ZEN), an estrogenic mycotoxin produced by several species of Fusarium fungi, is a common contaminant of cereal-based food worldwide. Due to frequent occurrences associated with high levels of ZEN, maize oil is a particular source of exposure. Although a European maximum level for ZEN in maize oil exists according to Commission Regulation (EC) No. 1126/2007 along with a newly developed international standard method for analysis, certified reference materials (CRM) are still not available. To overcome this lack, the first CRM for the determination of ZEN in contaminated maize germ oil (ERM®-BC715) was developed in the frame of a European Reference Materials (ERM®) project according to the requirements of ISO Guide 35. The whole process of CRM development including preparation, homogeneity and stability studies, and value assignment is presented. The assignment of the certified mass fraction was based upon an in-house study using high-performance liquid chromatography isotope dilution tandem mass spectrometry. Simultaneously, to support the in-house certification study, an interlaboratory comparison study was conducted with 13 expert laboratories using different analytical methods. The certified mass fraction and expanded uncertainty (k = 2) of ERM®-BC715 (362 ± 22) μg kg−1 ZEN are traceable to the SI. This reference material is intended for analytical quality control and contributes to the improvement of consumer protection and food safety. Graphical abstract


2021 ◽  
Vol 17 (1) ◽  
pp. 35-45
Author(s):  
M. Y. Medvedevskikh ◽  
N. L. Vostrikova ◽  
A. S. Sergeeva ◽  
V. V. Studenok

The article presents the application of the lyophilization system for preparation of reference materials (RM) for composition of nutritive products samples. The purpose of the research was the development of lyophilization procedure of RM for composition of poultry meat samples preparation with certified values of mass fraction of moisture, nitrogen (protein) and fat.The poultry meat of two types was used as the primary material for RM for poultry meat composition preparation -1) white meat (chicken breast); 2) red meat (chicken thigh). The procedure included pounding, boiling, freezing and lyophilisation (syn. freeze drying). The researches for homogeneity were implemented with hot air dryer standard system from the State primary standard GET 173-2017. Measurement of nitrogen (protein) mass fraction was performed on State secondary standard GVET176-1-2010. Measurements of fat mass fraction were performed with accordance to State Primary Reference Measurement Procedure.The total time of lyophilization process for samples № 1 and № 2 was 19 and 28 hours, respectively. The total mass loss for sample № 1 was about 63 %, for sample № 2 was about 65 %. The difference in material moisture mass fraction values of materials dried on different trays of freeze dryer was statistically significant, i. e., material was non-homogeneous. To obtain a homogeneous material, an additional homogenization procedure was performed: grinding in a laboratory mill, sieving through a sieve, thorough mixing and conditioning. The certified values of moisture, nitrogen, protein, fat mass fraction for the sample № 1 were accordingly 4,5 %, 14,74 %, 92,1 %, 7,9 %. The same values in the same sequence were 6,3 %, 12,21 %, 76,3 %, 23,8 %.The procedure of lyophilisation was developed for production of reference materials for composition of boiled and freeze-dried poultry meat. The usage of this lyophilisation system allowed to ensure a RM expiration date of six months at ambient temperature of (7±3) °C and relative humidity no more than 60 %. The Reference Materials for composition of boiled and freeze-dried poultry meat was added into Register of certified RMs under № GSO 11276-2019 by the results.


Author(s):  
Hang Nguyen Thi ◽  
Phuong Thao Le Thi ◽  
Huu Cuong Dang ◽  
Huyen Trang Luu Thi ◽  
Hong Hao Le Thi ◽  
...  

Vitamins are essential nutrients commonly found in food products in general and health supplements in particular. In order to accurately evaluate product quality, laboratories need to use reference material in analysis, proficiency assessment, method validation and ensure the validity of the results. The use of reference materials plays an important role in the quality control of test results and is a mandatory requirement for laboratories wishing to demonstrate appropriate competence as required by ISO/IEC 17025:2017. The need to provide reference materials for laboratories is huge. However, at present, there are very few domestic organizations that can produce reference materials, while the cost of buying reference materials from reputable firms in the world is expensive. In this study, we introduced the procedure and production reference materials for the analysis of B-group vitamins (B1, B2, B6). These reference materials were evaluated for homogeneity and stability in 322 days. The certified values are consistent with the concentrations of substances present in normal samples in practice. The measurement uncertainty ranges from 14.5 - 23.3 %. The reference materials can be used for internal quality control for domestic laboratories and is also a premise for further research on standard samples with different matrix and analytical criteria.


2019 ◽  
Vol 59 (8) ◽  
pp. 60-68
Author(s):  
Alina R. Krivosheeva ◽  
◽  
Anna V. Ananeva ◽  
Elvira N. Tarazova ◽  
Tatiana A. Eneykina ◽  
...  

The standard samples (SSs) of the compositions of hexogen (SS of Hxg), octogen (SS of Oct), ETN (SS of ETN) solutions in acetonitrile have been developed and certified for the first time. When approving each of aforesaid types of SSs, the interval of the permissible certified values has been determined as a range from 4.95 mg/dm3 to 5.05 mg/dm3 with an expanded uncertainty (k = 2) and the bounds of a relative error (P = 0.95) of no more than 1.8 %. The standard sample of the composition of a trinitrotoluene solution in acetonitrile (SS of 2,4,6-TNT) with the improved metrological characteristics in comparison with the analogue (SSS 9116-2008) has been developed and certified. The interval of the permissible certified values of SS of 2,4,6-TNT was from 4.95 mg/dm3 to 5.05 mg/dm3, the expanded uncertainty (k = 2) with the bounds of the relative error (P = 0.95) was 1.5%, which was 5 % less than the analogue. The improving of the metrological characteristics of the developed SSs has been obtained by the preliminary physical cleaning of the standard explosives from the impurities, which were taken for work. The two-fold recrystallization from acetone was used for cleaning of hexogen and ETN, the one-fold recrystallization from methanol was used for trinitrotoluene, the one-fold recrystallization of explosives from acetone in the complex with dimethylformamide (DMF) was used for octogen.


2019 ◽  
Vol 14 (3-4) ◽  
pp. 17-32 ◽  
Author(s):  
A. G. Budko ◽  
A. Y. Mikheeva ◽  
A. I. Krylov

The paper presents information on the development of a new certified reference material (CRM) for mass fraction of dioxins in animal fat, with established metrological traceability. A procedure for preparing and certifying CRM material is given. The GC–LRMS method with isotopic dilution was used as an analytical method for establishing certified characteristics. The uncertainties due to inhomogeneity and instability of the CRM material were estimated in order to account for their contribution to the uncertainty of certified values. In addition, the results of interlaboratory comparisons (ILC) for an experimental batch of the developed CRM are presented. Measurement results provided by ILC participants are shown to be in good agreement with the certified characteristics of the CRM. The certified values of dioxin mass fractions (PCDF group) in the CRM material are established to vary from 1 to 1000 ng / kg, with the relative expanded uncertainty ranging from 10 to 20 %.


2020 ◽  
pp. 64-70
Author(s):  
Mariya Y. Medvedevskikh ◽  
Anna S. Sergeeva

The article raises the problem of ensuring metrological traceability of the measurement results of indicators of quality and nutritional value for food products and food raw materials: water (moisture), nitrogen (protein, crude protein), fat, ash and carbohydrates. The problem under consideration can be solved by applying reference materials of food composition, traceable to state primary measurement standards GET 173-2017 and GET 176-2019 and primary reference measurement procedures (PRMP), for attestation of measurement procedures and accuracy checking of measurement results. The article discusses the results of the PRMP development of mass fraction of fat, ash and carbohydrates in food products and food raw materials, as well as mass fraction of crude fat (oil content) in oil crops seeds and products based on them. The paper also presents metrological characteristics of reference materials of composition of dry dairy products, grain-milk dry porridges for nutrition of babies, grain dry porridges for nutrition of babies, egg powder, freeze-dried meat products, animal feed. The results of the work allow for building a chain of metrological traceability from GET 173-2017, GET 176-2019 and PRMP to routine measurement procedures, thereby ensuring the uniformity of measurements of nutritional value of food products.


2019 ◽  
Vol 85 (6) ◽  
pp. 11-24
Author(s):  
I. V. Nikolaeva ◽  
A. A. Kravchenko ◽  
S. V. Palessky ◽  
S. V. Nechepurenko ◽  
D. V. Semenova

Two methods — ICP-MS and ICP-AES are used for certification of the new reference material — needles of Siberian pine (NSP-1). Techniques of the analysis include decomposition of plant samples in two different ways: acid digestion in a microwave system MARS-5 and lithium metaborate fusion followed by ICP-MS and ICP-AES analysis of the solutions. Simultaneous determinations of all the elements were carried out in low, medium and high resolution using SF-mass-spectrometer ELEMENT and atomic-emission spectrometer IRIS Advantage with external calibrations and internal standards (In — ICP-MS, Sc —ICP-AES). Middle and high resolutions of ICP mass spectrometer were used for interference corrections. Data obtained by ICP-MS and ICP-AES with different decomposition techniques are in good agreement. The ICP-MS and ICP-AES techniques have been validated by the analysis of three plant reference materials: LB-1 (leaf of a birch), Tr-1 (grass mixture) and EK-1 (Canadian pondweed). These techniques were used for the determination of 38 elements in the new reference material NSP-1. Relative standard deviations for most of the determined elements were below 10%. Combination of ICP-MS and ICP-AES techniques for certification of the new reference material makes it possible to expand the set of elements to be determined and to reduce the total analysis time.


Author(s):  
Zengmeng Zhang ◽  
Jinkai Che ◽  
Peipei Liu ◽  
Yunrui Jia ◽  
Yongjun Gong

Compared with pneumatic artificial muscles (PAMs), water hydraulic artificial muscles (WHAMs) have the advantages of high force/weight ratio, high stiffness, rapid response speed, large operating pressure range, low working noise, etc. Although the physical models of PAMs have been widely studied, the model of WHAMs still need to be researched for the different structure parameters and work conditions between PAMs and WHAMs. Therefore, the geometry and the material properties need to be considered in models, including the wall thickness of rubber tube, the geometry of ends, the elastic force of rubber tube, the elongation of fibers, and the friction among fiber strands. WHAMs with different wall thickness and fiber materials were manufactured, and static characteristic experiments were performed when the actuator is static and fixed on both ends, which reflects the relationship between contraction force and pressure under the different contraction ratio. The deviations between theoretical values and experimental results were analyzed to investigate the effect of each physical factor on the modified physical model accuracy at different operating pressures. The results show the relative error of the modified physical model was 7.1% and the relative error of the ideal model was 17.4%. When contraction ratio is below 10% and operating pressure is 4 MPa, the wall thickness of rubber tube was the strongest factor on the accuracy of modified model. When the WHAM contraction ratio from 3% to 20%, the relative error between the modified physical model and the experimental data was within ±10%. Considering the various physical factors, the accuracy of the modified physical model of WHAM is improved, which lays a foundation of non-linear control of the high-strength, tightly fiber-braided and thick-walled WHAMs.


Author(s):  
Yanwei Liu ◽  
Leyun Wang ◽  
Huan Zhang ◽  
Gaoming Zhu ◽  
Jie Wang ◽  
...  

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