Applicability of two separation methods for elemental analysis of typical agricultural biomass in China

Abstract

China still lacks standardized methods for element compositional analysis of agricultural biomass, in particular crop straw and livestock manure, which severely restricts the efficiency of the comprehensive utilization of agricultural biomass. Two separation methods, namely adsorbed-desorbed separation (AS) and chromatographic separation (CS), were applied to simultaneously analyze the carbon, hydrogen, nitrogen, and sulfur elements in major agricultural biomass. The optimal sizes of 1.00 mm for crop straws and 0.50 mm for livestock manure were obtained through optimization experiments. Afterwards, the sample mass was considered on two different elemental analysis instruments. From the metrological characteristics and variance analysis, a sample mass of 40 mg of the AS method was applicable for all the agricultural biomass, even with a content of 0.5%. On the other hand, 5 mg of the CS method was suitable for agricultural biomass with contents greater than 1.5%. It is recommended that samples should be kept free of impurities and completely homogeneous, especially for livestock manure. The results provide significant data for establishing a national standard system in the near future.