Metrological support of phthalate content measurements: reference material for the composition of a solution of six priority phthalates in methanol

The article provides information on the development of a new reference material (RM) for the composition of a solution of six priority phthalates (dimethyl phthalate, diethyl phthalate, di(n-butyl) phthalate, benzyl butyl phthalate, bis(2-ethylhexyl) phthalate, di(n-octyl) phthalate) in methanol provided with metrological traceability to GET 208-2019 (GET 208). The procedure for the preparation and certification of RMs is shown, including the estimation of homogeneity and stability. Pure organic substances (phthalates) characterized on GET 208 were used as the starting material for the RM. The RM material was prepared by weight and volume-weight methods. The stability study of the RM was carried out by the isochronous procedure. The RM certified values are the mass fraction and mass concentration of individual phthalates in the solution. When calculating the uncertainty budget for RM certified values, contributions from the purity of the starting materials, RM preparation procedures, heterogeneity, and long-term instability were taken into account. The relative expanded uncertainty of the certified values does not exceed 2 %. As a result, a certified reference material (CRM) was developed and approvedfor the composition of a solution of ortho-phthalic acid esters (phthalates) in methanol GSO 11366-2019. The practical significance of the application of GSO 11366-2019 is to ensure the metrological traceability of RM to the corresponding SI units reproduced on GET 208. The developed CRM can be applied in resolving any measuring tasks and performing a full range of metrological works.

Application of the lyophilization system for preparation of reference materials for composition of nutrition products

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.

Analysis of Aristolochia Longa L. Medicinal Plant from Algeria

In recent time, the therapeutic use of medicinal plants has increased all over the world. The efficacy of herbs for curative purposes is often accounted of its mineral and organic constituents. Neutron activation analysis (INAA) has been applied to mineral determination of Aristolochia Longa (bereztem), medicinal plant used to cure some diseases observed in Algeria especially cancer. In this work the mass fractions of Cr (15.22 ± 3.5 μg/g), Na (269.98 ± 25.01 μg/g), La (0.478 ± 0.041 μg/g), K (1.33 ± 0.23 μg/g), Br (1.2 ± 0.19 μg/g), As (0.697 ± 0.038) and Sb (66.09 ± 11.24 μg/g), were determined. This herb was collected from Taourirt Aden Berber village situated in Northern Algeria. Five elements were quantified in certified AIEA standards IAEA-V10 and IAEA-SL1 for checking the accuracy of our procedure. It was noteworthy the values obtained from this work are in good agreement with the certified values, the Z-score values for all elements were |Z| < 3. We believe that herb is natural and harmless compared with chemical drugs. Unfortunately the potential toxicity due to the Aristolochia Acids content has required the analysis of Aristolochia Longa by CG/MS and HPLC to highlight this compound. The standard of Aristolochic Acid (Sigma A5512-25 mg Yellow powder lot # wxbb6331VPCODE) was used as reference.

Determination of titanium dioxide in cement by Microwave Digestion-VIS Spectrophotometry

A new method to determine titanium dioxide in cement by Microwave Digestion-DAPM VIS Spectrophotometry which has many advantages such as simple operation, safe and fast, dissolve completely is presented in this paper. The determination conditions and working parameters of the microwave digestion instrument including the species and dosage of digestion reagent, wavelength, reaction time and the dosage of DAPM were optimized. The results show that samples were dissolved by HNO3-HF-H2O2, 395nm as the wavelength and 12mL of DAPM. The method has been validated by determination of titanium dioxide in national standard reference materials of GBW03201, GBW03201c, GBW03207 and GBW03205. The results were in agreement with certified values and the RSD was 1.07%-4.52%. The recovery ratio was ranging from 91.8% to 108.0% and the ｜△lgC｜was less than 0.018. Comparison with the traditional digestion method that analytical cement samples of Sichuan, there is no significant difference between the two methods by Student's t test. This new method provide a new way for quick and accurate to determine the content of titanium dioxide in cement.

Development of certified reference materials set for opened porosity of solid substances and materials

The article deals with data of research for development of certified reference materials set for opened porosity of solid substances and materials (imitators) (OPGP SO UNIIM set) GSO 11116-2018/GSO 11119-2018. The certified values of open porosity are determined using a gas pycnometer. Certified reference materials are intended for certification of measurement techniques and control of the accuracy of open porosity measurement results for petrophysical studies of core. Certified reference materials can be used for calibration, verification of open porosity measurements of rock and for testing of measuring instruments. A complete budget of the CRM uncertainty is presented, taking into account changes in ambient temperature when it used in testing and calibration laboratories.

DEVELOPMENT OF STANDARD SAMPLES OF MAGNESIUM ALLOYS VML20 AND VMD16

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.

The question of metrological traceability of COOMET reference materials. Pt. 1. International practice on traceability establishment of reference materials’ certified values

The multiplication of national units transfer instruments with established values of metrological traceability in international organisations is one of the most actual development directions for a large number of countries, inasmuch as this direction contributes to the solution of a global problem of measurement results comparability which were received for various objects in different times in different parts of the world as well as indicates the high quality of measuring capabilities of an organisation or a country. The paper contains issues of establishment of metrological traceability of results of physicochemical measurements. The international practice on traceability establishment of reference materials’ certified values is described in the work. The authors also provided a brief overview of internationally accepted fundamental concepts of reference materials metrological traceability demonstration.

A new certified reference material for size and shape analysis of nanorods using electron microscopy

A new certified reference material (CRM) for size and shape analysis of elongated nanoparticles has been developed by the European Commission’s Joint Research Centre. The CRM consists of titanium dioxide nanorods dispersed in 1-butanol, was coded ERM-FD103 and has been certified for different electron microscopy–based operationally defined measurands such as the modal and median values of the particle number-weighted distributions of the minimum and maximum Feret diameter, the maximum inscribed circle diameter, the area-equivalent circular diameter and the aspect ratio. The nanorods have nominal dimensions of 15 nm in width and 55 nm in length. Homogeneity and stability measurements were performed using transmission electron microscopy. The relative standard uncertainty for homogeneity ranged from 0.3 to 1.7%. No significant instability was detected for a shelf life of 18 months and a storage temperature of 18 °C. The certified values have been determined from the results of an interlaboratory comparison in which qualified expert laboratories participated with scanning and transmission electron microscopy. The certified values are traceable to the unit of length in the International System of Units, the metre, and the relative expanded uncertainties (confidence level of approximately 95%) range from 4 to 6%. These properties allow the CRM to be used for quality assurance and calibration of electron microscopy methods for nanoparticle size and shape analysis in ranges relevant for the implementation of EU legislation related to nanomaterials. The presented study discusses the purpose and results of the different steps that were followed to turn an industrially relevant raw titanium dioxide nanorod material into a fit-for-purpose CRM. Graphical abstract

Application of k0-INAA Method in Preliminary Characterization of KRISS Urban Airborne Particulate Matter Certified Reference Material

We report comprehensive elemental composition studies on the average urban airborne particulate matters (PMs) collected in the Greater Seoul area, Korea, in 2019 to identify regional and chronological characteristics of the sample as a candidate for certified reference material (CRM), using k0-based single comparator instrumental neutron activation analysis (k0-INAA). The method was successfully validated by comparing the analysis result of a similar matrix CRM (SRM 1648a urban particulate matter) of National Institute of Standards and Technology, USA, with corresponding certified values. The same methodology was applied to determine various elements in candidate environmental materials for future CRM development, including the urban PMs and incineration ashes, to investigate the possibility of using k0-INAA for certification of relevant reference materials. In total, 46 elements in the urban PM sample were analyzed and their concentration levels were compared with the urban PMs collected in the 1970s in St. Louis, USA. Urban PMs of Korea Research Institute of Standards and Science in 2019 contain significantly lower levels of hazardous elements, such as As, Cd, Cr, Hg, and Pb, as compared to those of the 1970s, which can be attributed to the reduced air pollution by environmental regulation and technological innovation. The potential major source of urban airborne PMs was also discussed.

The Implications of HClO4 for Dissolving Large Masses of Low Level Os in Metal Sulfides and Factors that Influence Re-Os Dating

In general, no more than 1 g of metal sulfide can be completely digested in 20 mL of inverse aqua regia using the Carius tube technique. In this study, the sample weight increased after adding HClO4 to inverse aqua regia while the volume of acid concurrently decreased significantly. Three grams of metal sulfide were digested in 12 mL of acid (3 mL of HClO4 and 9 mL of inverse aqua regia) via the HClO4-inverse aqua regia method. The results using molybdenite reference materials JDC and HLP mixed with 3 g of pyrite were consistent with certified values. Compared to the traditional method, the HClO4-inverse aqua regia method could dissolve a larger sample mass (3 g) with a smaller volume of acids (12 mL). We simultaneously found that the oxidation of digestion acids greatly affected the Os signal but had no influence on the equilibrium of isotope exchange between 185Re and 190Os spikes in Re and Os samples. Remarkably, the heating temperature was the most significant factor influencing the equilibrium of isotope exchange, and the Os in a sample was not equilibrated with the spike until the heating temperature reached 190 °C.