Simultaneous determination of local anesthetics including ester-type anesthetics in human plasma and urine by gas chromatography mass spectrometry with solid-phase extraction

The present study describes the simultaneous determination of seven differe nt kinds of local anesthetics and one metabolite by GC-MS with solid-state extraction: Mepivacaine, propitocaine, lidocaine, procaine (an ester-type l ocal anesthetics), cocaine, tetracaine (an ester-type local anesthetics), d ibucaine (Dib) and monoethylglycinexylidide (a metabolite of lidocaine) wer e clearly separated from each other and simultaneously determined by GC-MS using a DB-1 open tubular column. Their recoveries ranged from 73-95% at th e target concentrations of 1.00, 10.0 and 100 mu g/ml in plasma, urine and water. Coefficients of variation of the recoveries ranged from 2.3-13.1% at these concentrations. The quantitation limits of the method were approxima tely 100 ng/ml for monoethylglycinexylidide, propitocaine, procaine, cocain e, tetracaine and dibucaine, and 50 ng/ml for lidocaine and mepivacaine. Th is method was applied to specimens of patients who had been treated with dr ip infusion of lidocaine, and revealed that simultaneous determination of l idocaine and monoethylglycinexylidide in the blood and urine was possible. (C) 1999 Elsevier Science B.V. All rights reserved.