For better understanding the communication of microorganism with each other and their environment, analytical techniques providing high resolution were used for the analysis of diffusible molecules produced by bacteria.The target signal molecules which are part of quorum sensing, were derivatives of N-acyl homoserine lactones (AHLs) produced by several Gram-negative bacterias and hydroxyl-alkyl-quinolones (HAQ) produced by some Pseudomonas species.These were analysed by ultra high pressure chromatography namely UPLC, Fourier transformation ion cyclotron mass spectrometry (ICR_FT/MS), capillary electrophoresis and gas chromatography.A non-specific sample preparation based on solid phase extraction were developed allowing the screening of possible metabolites among the target analysis.Since generally more than one derivative of these signalling molecules are produced in the nature, a screening method combining UPLC or CE and ICR_FT/MS were built-up without chemical synthesis of the solutes that allows the identification of further putative signalling molecules.Off-line, at-line and on-line combination of these analytical techniques gave the possibility for rapid and reliable identification and quantification of the derivatives of AHLs and HAQs from different matrices like cell-free complex-medium and extracts of plant tissues.