Determination of biogenic component in liquid fuels by the ¹⁴C direct LSC method by using quenching properties of modern liquids for calibration

The fraction of biogenic component within various types of materials that can be used as fuels for energy production and transport can be determined by measuring their ¹⁴C activity. The method is based on different ¹⁴C signatures of the biogenic and the fossil components: while the biogenic component reflects the modern atmospheric ¹⁴C activity, no ¹⁴C is present in fossil fuels. A direct measurement of the ¹⁴C content in liquid fuel by liquid scintillation counter is a simple and fast technique but has a main disadvantage: different liquid colors cause different quenching properties and affect the measurement efficiency. We propose a new evaluation technique that uses liquids of different colors to construct modern and background calibration curves. Various binary mixtures of biogenic liquids have been used to verify the relation between the count rate and the quenching parameter. Mixtures of a biogenic and a ¹⁴C-free liquid demonstrated the potential of the proposed technique for determining the biogenic fraction of a mixture. - Highlights: • Radiocarbon method is applicable for biogenic component determination. • Biogenic component in liquids determined by direct measurement in LSC. • New evaluation technique is proposed for liquid fuels. • Quenching of modern liquids is used for calibration. • Quenching curve does not depend on chemical composition of the liquid.