Metabolomics approach: a new application in suspect screening of 36 antibiotics in soil

Soil contamination by antibiotics is a worldwide environmental issue, and it is essential to develop suspect screening methods of antibiotics in soil for their comprehensive risk assessment. In this study, a novel metabolomics approach by seeking 'marker compounds' on behalf of 36 antibiotics in the forest topsoil was developed based on the results of high performance liquid chromatography tandem mass spectrometry. About 10 & mu;g/kg antibiotic concentration in soil was designed for metabolomics analysis. Principal component analysis and orthogonal partial least squares discriminant analysis support the existence of variables with evident inter-group differences, which were further discerned by S-plot plots, permutation tests and variable importance in projection to pick eligible variables as 'marker compound' candidates. Pairwise t-test and fold change of concentration were employed to validate these candidates. The results indicate that 36 'marker compounds' were all correctly screened out, together with the good practicability test in the rural greenhouse soils, proving the feasibility of this novel metabolomics method, which was expected to present great superiority and wide application future in suspect screening of pollutants. The limits of detection for 36 antibiotics in soil were calculated to be 0.6-2.6 & mu;g/kg.