A newly modified Syncore Analyst or Polyvap overcomes these shortcomings while fulfilling the following requirements:   

• The operational steps for the SPE process, i.e. conditioning, enrichment, washing and elution, shall be carried out without interruption to reduce sample handling and the amount of glassware used.   * Concentration of the eluates to pre-defined residual volumes is achieved on the same instrument without any interruption or exchange of equipment to make sample transfer obsolete and to reduce the amount of valuable bench top space and equipment costs.   * The flow of each port must be individually adjustable to handle samples with considerable differences in sorbent consistencies and/or matrix constituents.   * Avoidance of cross-contamination for both SPE work-up and parallel evaporation is crucial to guarantee no interferences of adjacent samples.   * High recoveries for both steps are crucial, particularly for volatile compounds.   

  The key feature is a three-way stopcock which allows separating the liquid passed through a SPE cartridge into either a waste vessel or a collecting vessel. The eluate of the collecting vessel is then evaporated to dryness or a pred-defined residual volume without any sample handling between the SPE work-up stage and evaporation stage.