We purchased the N-EVAP for PFOS analysis by EPA 537.1 and EPA 533. The N-EVAP is referenced in the method by the EPA. We initially looked at other brands costing 3x as much that were electronically controlled but thought if this is what the EPA used we should use it as well. It works well and we completed all start-up QC for regulatory approval using the N-EVAP. The only complaint would be that you have to be hands-on at the end of the evaporation to regularly adjust the needle height and nitrogen flow.
Application :
EPA 537.1 & 533