- Authors: M.M. López-Guerrero, M. Hernández-Mesa, C. Cruces-Blanco, A.M. García-Campaña
- Reference: Electrophoresis 36 (2015) 2961-2967
The simultaneous determination of usually employed anaesthetics (procaine, lidocaine and bupivacaine) has been developed and validated using capillary electrophoresis with ultraviolet detection at 212 nm. The separation of these three drugs has been achieved in less than 7 min, using a temperature of 25º C and 25 kV, with a 150 mM citrate buffer (pH 2.5) as background electrolyte. Field amplified sample injection (FASI) has been used for on-line sample preconcentration. Ultrapure water and acetonitrile 50/50 (v/v) mixture gave the greatest enhancement factor when it was employed as injection solvent. Injection voltage and time were optimized, being 13 kV and 13 s, the optimum values respectively. To avoid the possible irreproducibility associated with the electrokinetic injection, an internal standard such as tetracaine, was employed. The instrumental detection limits (LOD s/n = 3) for the compounds ranged between 2.6 and 7.0 μg L−1 and the quantitation limits (LOQ s/n = 10) between 37.8 and 55.9 μg L−1. The detection limits obtained in real human urine samples ranged between 55.2 and 83.6 μg L−1 and the quantitation limits between 196.0 and 276.0 μg L−1. The proposed method has demonstrated its applicability to the analysis of these local anaesthetics in urine samples without any pretreatment, allowing the rapid determination of these target analytes.
