Certified Reference Material for the Composition of Phthalates in a Polymer Matrix Based on Polyvinyl Chloride

Abstract

   The purpose of the study was to develop a new CRM for the composition of the mass fraction of phthalates in a polymer matrix based on polyvinyl chloride for validation and/or verification of measurement methods such as GOST R ISO 8124-6-2021, GOST R ISO 14389–2016, GOST R ISO 16181–2015 etc.   In the study, a method for preparing the starting material of the CRM was tested and successfully implemented, and a critical analysis of methods for measuring the content of di(n-butyl)phthalate and di(2-ethylhexyl)phthalate was carried out. The gas chromatography/isotope dilution mass spectrometry method was chosen as the main method for a quantitative determination of the certified value of the measured value of the mass fraction of di(n-butyl)phthalate and di(2-ethylhexyl) phthalate. In accordance with RMG 93–2015, GOST 8.315-2019, and GOST ISO Guide 35–2015, the standard uncertainty of the certified CRM value from the characterization method, from heterogeneity and instability of the material was assessed. The expanded uncertainty of the certified value was calculated. As a result of the work, a new CRM for the composition of the mass fraction of phthalates in a polymer matrix based on polyvinyl chloride was approved. Certified CRM values are metrologically traceable to GET 208 in accordance with metrological hierarchy according to the verification schedule through GSO 11366–2019. A CRM composition for the mass fraction of phthalates in polyvinyl chloride has the following standardized metrological characteristics: mass fraction of di(n-butyl)phthalate – 0.046 mg/g and di(2-ethylhexyl)phthalate – 45.8 mg/g; the relative expanded uncertainty at k = 2, P = 0.95 is 10 %. The CRM is stored in sealed bottles in a dry place, protected from light, at a temperature from 2 °C to 8 °C. The shelf life of the CRM is 3 years. The developed CRM can be used in solving any measurement problems and performing various types of metrological work, including metrological purposes in the field of polymer and rubber industries, food industry, environmental protection, and scientific research.