Identification and authentication of pharmaceuticals can be confidently achieved by mass spectrometry, which provides plentiful molecular information to probe the chemical nativity of all types of samples. Owing to the complexity of the tablet composition, targeted analytes must be separated from matrices before detection by mass spectrometry. The separation methods include HPLC , GC , CE , lab-on-chip system [4, 5], etc. These methods need laborious and time-consuming sample preparation. In 2004, Cooks et al.  demonstrated that analyte ions can be produced using desorption electrospray ionization (DESI) in an open-air environment without separating the matrix of real-world samples. From then on, more than 30 ionization methods have been reported for direct creation of analyte ions in ambient conditions such as direct analysis in real time (DART) , low temperature plasma (LTP) , extractive electrospray ionization (EESI) , and desorption atmospheric pressure chemical ionization (DAPCI) . By using DESI and other ambient ionization techniques, throughput of mass spectrometry analysis was dramatically improved because no/minimal sample pretreatment was required [11–14].