Разработка государственного вторичного эталона и стандартных образцов состава на основе жидкостной и газовой хроматографии

The article is devoted to the development of the state secondary measurement standard of mass fraction units and mass (molar) concentration of organic components in liquid and solid substances and materials based on gas and liquid chromatography. The composition of the state secondary measurement standard, as well as the results of evaluating metrological characteristics have been considered. The problem of ensuring the traceability of measurement results to SI units is given in the article. Two approaches are proposed for obtaining a unit from the state primary standard of mass (molar) fraction units and mass (molar) concentration of organic components in liquid and solid substances and materials based on liquid and gas chromatography-mass spectrometry with isotopic dilution and gravimetry GET 208-2014: by comparing and using transfer standards. Examples of implementing the indicated approaches used during the development of reference materials of toxic substances, namely a certified reference material for composition of p,p-DDT (p,p-DDT, CRM of UNIIM) and a certified reference material for composition of benz(a)pyrene solution in acetonitrile (C20H12, CRM of UNIIM) are given. Results of determining metrological characteristics of reference materials including standard uncertainty due to characterization and standard uncertainties due to inhomogeneity, short and long-term instabilities are described.Статья посвящена разработке государственного вторичного эталона единиц массовой доли и массовой (молярной) концентрации органических компонентов в жидких и твердых веществах и материалах на основе газовой и жидкостной хроматографии. В работе представлен состав Государственного вторичного эталона, а также представлены результаты оценивания метрологических характеристик. Рассмотрена проблема обеспечения требования прослеживаемости результатов измерений до единиц СИ. Предложено два подхода получения единицы от Государственного первичного эталона единиц массовой (молярной) доли и массовой (молярной) концентрации органических компонентов в жидких и твердых веществах и материалах на основе жидкостной и газовой хромато-масс-спектрометрии с изотопным разбавлением и гравиметрии ГЭТ 208-2014: методом сличений и с помощью эталонов сравнения. Приведены примеры реализации указанных подходов, использованные в ходе разработки стандартных образцов токсичных веществ, а именно стандартного образца состава п,п-ДДТ (п,п-ДДТ СО УНИИМ) и состава раствора бенз(а)пирена в ацетонитриле (С20Н12 СО УНИИМ). Описаны результаты установления метрологических характеристик стандартных образцов, включая стандартную неопределенность, обусловленную способом определения аттестованного значения, а также стандартные неопределенности от неоднородности, кратковременной и долговременной нестабильности

Development of the state secondary measurement standard and certified reference materials for composition on the basis of liquid and gas chromatography

The article is devoted to the development of the state secondary measurement standard of mass fraction units and mass (molar) concentration of organic components in liquid and solid substances and materials based on gas and liquid chromatography. The composition of the state secondary measurement standard, as well as the results of evaluating metrological characteristics have been considered. The problem of ensuring the traceability of measurement results to SI units is given in the article. Two approaches are proposed for obtaining a unit from the state primary standard of mass (molar) fraction units and mass (molar) concentration of organic components in liquid and solid substances and materials based on liquid and gas chromatography-mass spectrometry with isotopic dilution and gravimetry GET 208-2014: by comparing and using transfer standards. Examples of implementing the indicated approaches used during the development of reference materials of toxic substances, namely a certified reference material for composition of p,p-DDT (p,p-DDT, CRM of UNIIM) and a certified reference material for composition of benz(a)pyrene solution in acetonitrile (C20H12, CRM of UNIIM) are given. Results of determining metrological characteristics of reference materials including standard uncertainty due to characterization and standard uncertainties due to inhomogeneity, short and long-term instabilities are described

CCQM-K102 Polybrominated diphenyl ethers in sediment

The key comparison CCQM-K102: Polybrominated diphenyl ethers in sediment was coordinated by the JRC, Directorate F – Health, Consumers & Reference Materials, Geel (Belgium) under the auspices of the Organic Analysis Working Group (OAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM). Thirtheen National Metrology institutes or Designated Institutes and the JRC participated. Participants were requested to report the mass fraction (on a dry mass basis) of BDE 47, 99 and 153 in the freshwater sediment study material. The sediment originated from a river in Belgium and contained PBDEs (and other pollutants) at levels commonly found in environmental samples. The comparison was designed to demonstrate participants' capability of analysing non-polar organic molecules in abiotic dried matrices (approximate range of molecular weights: 100 to 800 g/mol, polarity corresponding to pKow < -2, range of mass fraction: 1-1000 µg/kg). All participants (except one using ultrasonic extraction) applied Pressurised Liquid Extraction or Soxhlet, while the instrumental analysis was performed with GC-MS/MS, GC-MS or GC-HRMS. Isotope Dilution Mass Spectrometry approach was used for quantification (except in one case). The assigned Key Comparison Reference Values (KCRVs) were the medians of thirteen results for BDE 47 and eleven results for BDE 99 and 153, respectively. BDE 47 was assigned a KCRV of 15.60 µg/kg with a combined standard uncertainty of 0.41 µg/kg, BDE 99 was assigned a KCRV of 33.69 µg/kg with a combined standard uncertainty of 0.81 µg/kg and BDE 153 was assigned a KCRV of 6.28 µg/kg with a combined standard uncertainty of 0.28 µg/kg. The k-factor for the estimation of the expanded uncertainty of the KCRVs was chosen as k = 2. The degree of equivalence (with the KCRV) and its uncertainty were calculated for each result. Most of the participants to CCQM-K102 were able to demonstrate or confirm their capabilities in the analysis of non-polar organic molecules in abiotic dried matrices. Throughout the study it became clear that matrix interferences can influence the accurate quantification of the PBDEs, if the analytical methodology applied is not appropriately adapted and optimised. This comparison shows that quantification of PBDEs at the µg/kg low-middle range in a challenging environmental abiotic dried matrix can be achieved with relative expanded uncertainties below 15 % (more than 70 % of participating laboratories), well in line with the best measurement performances in the environmental analysis field.JRC.F.6-Reference Material

CCQM-K131 Low-polarity analytes in a multicomponent organic solution: polycyclic aromatic hydrocarbons (PAHs) in acetonitrile

Solutions of organic analytes of known mass fraction are typically used to calibrate the measurement processes used to determine these compounds in matrix samples. Appropriate value assignments and uncertainty calculations for calibration solutions are critical for accurate measurements. Evidence of successful participation in formal, relevant international comparisons is needed to document measurement capability claims (CMCs) made by national metrology institutes (NMIs) and designated institutes (DIs). To enable NMIs and DIs to update or establish their claims, in 2015 the Organic Analysis Working Group (OAWG) sponsored CCQM-K131 "Low-Polarity Analytes in a Multicomponent Organic Solution: Polycyclic Aromatic Hydrocarbons (PAHs) in Acetonitrile". Polycyclic aromatic hydrocarbons (PAHs) result from combustion sources and are ubiquitous in environmental samples. The PAH congeners, benz[a]anthracene (BaA), benzo[a]pyrene (BaP), and naphthalene (Nap) were selected as the target analytes for CCQM-K131. These targets span the volatility range of PAHs found in environmental samples and include potentially problematic chromatographic separations. Nineteen NMIs participated in CCQM-K131. The consensus summary mass fractions for the three PAHs are in the range of (5 to 25) μg/g with relative standard deviations of (2.5 to 3.5) %. Successful participation in CCQM-K131 demonstrates the following measurement capabilities in determining mass fraction of organic compounds of moderate to insignificant volatility, molar mass of 100 g/mol up to 500 g/mol, and polarity pKow < −2 in a multicomponent organic solution ranging in mass fraction from 100 ng/g to 100 μg/g: (1) value assignment of primary reference standards (if in-house purity assessment carried out), (2) value assignment of single and/or multi-component organic solutions, and (3) separation and quantification using gas chromatography or liquid chromatography