We are using the Florisil cartridges described in Method 3620B and we cannot find any that meet the performance checks described in Sec. 8 of the method. Specifically, we cannot get the recovery of trichlorophenol to be less than 5%.
While the use of the Florisil cartridges may require a bit of practice, the root cause of your problem may be the result of an editorial error in the "B" version of this method. At some point during the development of Method 3620B, the units for the cartridge check solution in Sec. 5.11 were changed to milligrams per liter when the units should be micrograms per liter (mg/L versus ug/L). As a result, the cartridge check solution is 1000 times more concentrated than intended and may overload the cartridges, allowing the trichlorophenol to break through. This editorial error was corrected in the latest version of the method, 3620C, which is available in Update V.