A new capillary electrophoresis (CE) method was developed and validated for screening human urine for 19 drugs of abuse.
Since its inception, CE has proven to have use in the analysis and detection of drugs of abuse due to its high efficiency, reduced sample volume, and rapid analysis; however, when used in standard operating models, CE is not sufficiently sensitive to be applied to trace analysis due to low injection volumes and limited detection path lengths. The current study determined that sample pre-concentration can provide an alternative approach for sensitivity improvement. Techniques, such as solid-phase extraction (SPE), liquid-liquid extraction, and solid-phase microextraction can be used in combination with CE to improve sensitivity. These extraction procedures can be performed through the use of sequential injection (SI) techniques. SI, a second-generation flow injection technique, involves the reduction of sample and reagent volume from milliliters to microliters. In addition, the full automation of the technique enables the entire process to be rapid and precise. Testing results are shown for each of the 19 drugs. The descriptions of materials and methods address chemicals and reagents, instrumentation, CE system, the preparation of standard solutions and samples, the SI-SPE procedure, and the CE procedure. Details are presented on CE development, SI-SPE development, and validation of the method. 4 figures, 2 tables, and 31 references