High throughput pyrogenic carbon (biochar) characterisation and quantification by liquid chromatography

Abstract

Characterisation and quantification of the carbonaceous polyaromatic structure of pyrogenic carbon (PyC) are of paramount importance to evaluate the role of PyC in soil carbon sequestration. A new method of rapid resolution liquid chromatography with UV diode array detection (RRLC-UV-DAD) was developed and is proposed to quantify benzene polycarboxylic acids (BPCAs), which are considered molecular markers of the aromatic structure of PyC. The proportion of aromatic carbon structures and the degree of aromatic condensation obtained from different PyC, i.e. different biomass pyrolysed at final temperature (450 °C), were quantified using the method of RRLC-UV-DAD. We showed that (i) the RRLC-UV-DAD analysis takes one quarter of the analysis time of conventional HPLC and half of the time of GC analysis, increasing BPCA analysis throughput; (ii) the optimised method showed high overall precision and low limits of quantification and (iii) PyC produced from different tropical biomass exhibited a wide range of BPCA yields and patterns.