Comparative study of the determination of bupivacaine in human plasma by gas chromatography-mass spectrometry and high-performance liquid chromatography

A comparison was made between high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) as methods for determining bupivacaine in human plasma. Both methods utilized pentycaine as an internal standard, were found to be linear in the range 5–320 ng and had acceptable precision and accuracy. The precision for the HPLC method was better than that for the GC-MS method. The limits of detection of the HPLC and GC-MS methods were ca. 1.0 and 0.1 ng, respectively. Good agreement between the HPLC and GC-MS methods was obtained for the analysis of samples taken from a patient receiving bupivacaine topically. For most purposes the HPLC method would be slightly better. However, for samples containing interfering peaks GC-MS provides a higher degree of resolution from such interferants.