Valerio Ferracci

A metrological approach to improve accuracy and reliability of ammonia measurements in ambient air

The environmental impacts of ammonia (NH3) in ambient air have become more evident in the recent decades, leading to intensifying research in this field. A number of novel analytical techniques and monitoring instruments have been developed, and the quality and availability of reference gas mixtures used for the calibration of measuring instruments has also increased significantly. However, recent inter-comparison measurements show significant discrepancies, indicating that the majority of the newly developed devices and reference materials require further thorough validation. There is a clear need for more intensive metrological research focusing on quality assurance, intercomparability and validations. MetNH3 (Metrology for ammonia in ambient air) is a three-year project within the framework of the European Metrology Research Programme (EMRP), which aims to bring metrological traceability to ambient ammonia measurements in the 0.5–500 nmol mol−1 amount fraction range. This is addressed by working in three areas: (1) improving accuracy and stability of static and dynamic reference gas mixtures, (2) developing an optical transfer standard and (3) establishing the link between high-accuracy metrological standards and field measurements. In this article we describe the concept, aims and first results of the project.

An investigation of the matrix sensitivity of refinery gas analysis using gas chromatography with flame ionisation detection.

The response of a flame ionisation detector (FID) on a gas chromatograph to methane, ethane, propane, i-butane and n-butane in a series of multi-component refinery gas standards was investigated to assess the matrix sensitivity of the instrument. High-accuracy synthetic gas standards, traceable to the International System of Units, were used to minimise uncertainties. The instrument response exhibited a small dependence on the component amount fraction: this behaviour, consistent with that of another FID, was thoroughly characterised over a wide range of component amount fractions and was shown to introduce a negligible bias in the analysis of refinery gas samples, provided a suitable reference standard is employed. No significant effects of the molar volume, density and viscosity of the gas mixtures on the instrument response were observed, indicating that the FID is suitable for the analysis of refinery gas mixtures over a wide range of component amount fractions provided that appropriate drift-correction procedures are employed.

Production and measurement of large-area moisture barriers for electronic applications

The use of organic electronic materials, combined with the desire to produce lightweight & low cost flexible devices, raises the need to develop a commercially viable technology which limits the impact of the active materials intrinsic environmental instability. CPI has been involved in the area of barrier film and encapsulation development for many years and with its development with Beneq of R2R Atomic Layer Deposition (ALD) processes is actively engaging with the industry to meet this technology need. This work reviews the existing technologies and highlights the barrier and associated metrology technologies being developed at CPIs National Printable Electronics Facility, including a variant of calcium-test which has been calibrated to the mass standard. The aim of all this work is to reduce costs and improve the manufacturability of these materials for a commercial/industrial environment.