Rapid untargeted screening for drug residues in animal tissues with liquid microjunction surface sampling probe mass spectrometry.

An untargeted screening method for the rapid identification of veterinary drug residues in incurred animal tissues using liquid microjunction surface sampling probe mass spectrometry (LMJSSP-MS) was developed. Current analytical methods for veterinary drug residue screening involve lengthy sample preparation, extraction, and instrumental analysis steps. This method identifies veterinary drug residues in several different incurred animal tissues more quickly than conventional analytical methods. This LMJSSP-MS method uses an ambient ionization technology called liquid microjunction surface sampling probe along with a data dependent scan function of a quadrupole orbitrap mass spectrometer. Collected product ion spectra are searched against the mzCloud™ online mass spectral database to identify veterinary drug residues found in incurred animal tissue samples. Examples of veterinary drugs identified with this method include flunixin, tilmicosin, pentobarbital, xylazine, and ketamine. Optimization of method parameters is described and discussed. The limit of identification (LOI) of this method is estimated to be approximately 1 μg g-1 for xylazine and ketamine.