|SRC Principles Of Operation|
SRC operation is extremely simple and completely automated from start to finish. The entire process is shown below. A simple sample rack, similar to a rotary autosampler rack, is loaded with samples weighed into glass vials. The vials are capped with loose fitting PTFE caps (to prevent condensation from the top of the SRC chamber dripping into the vials). The rack is fitted to the chamber top which is lowered automatically into the chamber. The sample vials sit in liquid that provides a consistent “load” for the delivered microwave energy. This insures even heating and consistent conditions from run to run. The chamber clamp is secured automatically with the UltraCLAVE (manually with the UltraWAVE), and the chamber pressurized with N2 (40 bar). This prevents boiling of samples as the run starts and essentially acts as a “cover” over the samples, eliminating any possibility of cross contamination.
The microwave program starts and all samples are digested under the same conditions. When the heating cycle stops, water cooling rapidly cools the chamber to ambient temperature. The pressure is released, the chamber is opened and acid fumes are extracted - away from the operator. The rack is then simply removed, the samples are made up to volume, and are ready for analysis.