Variations of Florisil Activity: Method to Increase Retentive Properties and Improve Recovery and Elution Patterns of Insecticides

Abstract

The adsorptive capacity of 10 different lots of commercial Florisil (60-100 mesh) was tested by determining the recovery and elution patterns of 10 chlorinated and 6 organophosphate insecticides. Four lots were regular grade Florisil (calcined at 1200°F) and 6 lots were PR grade Florisil (calcined at 1250°F). All lots were tested as received and tested after washing with hot distilled water and re-igniting at 1250°F for 2.5 hr. Results indicated a wide variation in the activity and retentive properties of the untreated lots. Certain pesticides were not totally removed from the column by the respective eluant and some were irreversibly held on the column and not apparent in other eluants. After the washing and reigniting treatment, all lots of the PR Florisil gave satisfactory recovery and separation in the proper eluants. The lauric acid value was used to determine the quantity of Florisil to be placed on the column.