Detection of various local anesthetic ingredients such as tetracaine and prilocaine in illegally distributed drugs through GC-TOF MS and GC-MS.

Local anesthetic compounds are mixed with counterfeit products, which are claimed to be pharmaceuticals. Gas chromatography-time-of-flight mass spectrometry (GC-TOF MS) and GC-MS methods were used to simultaneously determine 18 local anesthetics and to identify illegal products. The GC-TOF MS method was first performed to determine the fragmentation patterns and structures of the 18 compounds and to qualitatively screen the samples. The GC-MS method was thoroughly validated for specificity, linearity, limit of detection, limit of quantification, accuracy, precision, and recovery. The samples were divided into liquid, cream, and other forms for testing, 65.6% (40/61) of which were adulterated with local anesthetics. Lidocaine was frequently identified in the analyzed samples, with a detection range of 0.153–164.0 mg/g. Furthermore, linearity was observed within the concentration range of 0.41–1.28, 2.29–2.43, and 1.83–16.3 mg/g for prilocaine, procaine, and tetracaine, respectively. Eugenol was detected in a single sample at 3.45 mg/g. In addition, three components were detected in one sample, posing adverse repercussions to human health when used in combination. Therefore, our analytical methods could contribute to the removal of illegal products containing pharmaceutical compounds.