Development of a novel solid phase extraction method for the analysis of bacterial quinones in activated sludge with a higher reliability.
Extraction and identification of bacterial quinones is becoming increasingly important. The main purpose of this research is to investigate the possibility of extracting quinones from activated sludge using supercritical fluid extraction and also to investigate the effect of various polar solvents in order to improve the yield. A ± 0.1 g freeze-dried activated sludge sample was extracted at 35C, 20 Mpa using supercritical carbon dioxide (scCO2). This technique was able to extract quinones, yet with very low yield. In order to enhance the yield, performance of scCO2 was improved by adding any modifiers to the fluid. Various polar solvents such as methanol, acetone, ethanol, and chloroform were investigated. By adding the modifiers, four ubiquinones and 12 menaquinones species were identified in 0.1 g dried activated sludge based on retention time and spectrum analysis. Among the tested various polar solvents, methanol showed to be the best modifier, based on the highest total quinone content extracted and the lowest dissimilarity index.