The analysis of organochlorine pesticides in soil and water samples can be hampered by coextracted matrix components contaminating the GC inlet and column, forcing labs to stop running samples and take instruments off-line for time-consuming maintenance. Florisil SPE cartridges are often used to clean up sample extracts (e.g., EPA Method 3620), but Resprep FL + CarboPrep Plus SPE cartridges (Resprep FL+CPP)—which contain both Florisil and carbon in a dual-bed, single-cartridge format—are much more effective at removing the high molecular weight contaminants that quickly foul GC inlets and take instruments down for maintenance.