Restricted access material (RAM) has been used in the packing of a solid-phase extraction (SPE) column for on-line extractions under turbulent flow conditions. The bio-compatible RAM material works by the principle of size exclusion in addition to conventional reversed-phase chromatography, thereby allowing the extraction and preconcentration of small analyte molecules from biological samples such as plasma. Using small column dimensions (0.76mm×50mm) and a consequently high linear velocity, turbulent flow was achieved during online sample extractions. The improved mass-transfer rate characteristic of turbulent flow allows fast sample cleanup without decreased extraction efficiency. The novel use of the RAM column, connected upstream to a C 18 monolithic column, allowed the direct injection, extraction, separation, and MS/MS detection of plasma samples spiked with rofecoxib in a span of 5min. Calibration curves obtained using this RAM turbulent flow coupled column method showed good linearity (R 2 >0.99) and reproducibility (%RSD≤7%). The lower limit of quantitation of rofecoxib in plasma samples was found to be 40ng/ml. The extraction method showed good recovery of rofecoxib from a plasma matrix with minimal signal loss and robustness after more than 200 plasma injections.