Empore Filter Aid 400 has been shown to improve flow rates and recoveries for separation and filtration of water samples containing suspended solids.  When placed on top of the Empore™ Extraction Disk at a depth of about 1 cm, Empore™ Filter Aid 400 acts as depth filter to inhibit the migration of suspended solids to the surface of the disk.  This reduces extraction time and improves rates and recovery of analytes.