High-performance liquid chromatography of seized drugs at elevated pressure with 1.7 μm hybrid C18 stationary phase columns

High-performance liquid chromatography (HPLC) separation of drugs at elevated pressure with 1.7 μm hybrid C18 stationary phase columns was investigated. This technique, which uses instrumentation engineered to handle the narrow peaks and high back pressures generated by 1.7 μm particle columns, provided significantly better resolution and/or faster analysis than conventional HPLC and capillary electrophoresis (CE). The use of 2 mm internal diameter (i.d.) columns of 3-10 cm length has been evaluated for the separation of basic and neutral drugs, drug profiling, and general screening (including acidic drugs). For these applications, compared to conventional HPLC and CE, it provided up to 12× and 3× faster analyses, respectively. Precision was excellent for both isocratic and gradient analyses. For retention time and peak area, RSDs of ≤0.1% were obtainable. Fifteen anabolic steroids and esters were well separated in a 2.5 min gradient. For drug profiling, compared to HPLC and CE, approximately twice as many peaks were resolved. HPLC at elevated pressure is also well suited as a general screening technique. Twenty-four solutes of varying drug classes including narcotic analgesics, stimulants, depressants, hallucinogens, and anabolic steroids were fully separated in a 13.5 min gradient.