A method for the simultaneous extraction, concentration, and quantitation of miliacin and 5-n-alkylresorcinols from soils and sediments

Abstract

The analysis of cereal biomarkers provides snippets of human-environmental interactions targeting questions of crop domestication and dietary practices of past societies. Commonly these markers are analysed from ceramics and lacustrine sediments to ensure an optimal preservation. In this paper, we propose a method for the simultaneous extraction, concentration, and quantitation of miliacin and 5-n-alkylresorcinols from terrestrial soils and sediments. After Soxhlet extraction, total lipid extracts from a modern and a prehistoric arable soil were purified by solid phase extraction, yielding successively a less polar and a more polar fraction containing miliacin and 5-n-alkylresorcinols, respectively. Gas chromatography – tandem mass spectrometry (GC-MS/MS) analysis using multiple reaction monitoring reliably detected miliacin and homologues of 5-n-alkylresorcinols from the investigated soils. The method in its current state appears to work better for miliacin than for ARs as evidenced by lower relative standard deviations (≤ 0.07), higher workup efficiencies (95 ± 15 %, n = 12) and recovery rates (between 74 and 82 %) independent from physiochemical soil characteristics. Future research requires optimisation of AR extraction efficiency from complex soil matrices, especially focussing on the interaction with reactive organic and mineral soil constituents. Nonetheless, this article demonstrates the applicability of the proposed method to simultaneously analyse miliacin and 5-n-alkylresorcinols from terrestrial soils and sediments, thus extending the analysis of cereal biomarkers to sample material that it has not or only rarely been applied to so far.