23.4. Eluate concentration using a vacuum automated parallel evaporator Parallel evaporation was performed using a Syncore Analyst with a 6 position rack attached to a vacuum pumplcontroller V 700/V-855, and recirculating chiller F-108 (Buchi Labortechnik AG, Flawil/Switzerland). Six sample glass vessels with working vol umes of 25-250 mL were used. The Syncore Analyst was equipped with a flushback module that condensed the vapor at the top of the vessels, gently rinsing the glass walls. The sample vessels had 3 ml. appendices at the bottom, cooled during evaporation, to facilitate the collection of the defined volume and to avoid evaporation to dryness (Fig. 1) The ethereal eluates at -20 oc were filled into the Analyst sam- ple vessels, leaving behind (attached to the glass bottles) residual moisture as ice. The heating temperature was set at 40 oC and