Development of a Novel Direct Capillary Spray Cartridge and its Application in Fast Mass Spectrometry Analysis of Drugs

There is an increasing need for on-site and rapid detection of drugs of abuse, especially with a large number of new designer drugs emerging. The combination of direct sampling ionization and miniature mass spectrometry (MS) system serves as a primary strategy for fast analysis of various drugs. In consideration of low ionization efficiency of current direct sampling techniques for some drugs, a novel direct capillary spray method was developed and a cartridge was designed. The workflow only required an analysis time less than 1 min, including fast sampling, analyte elution and direct MS analysis by a miniature mass spectrometer. The analytical performance was demonstrated by analyzing ephedrine, cocaine, ketamine, methamphetamine, MDMA, 1-(3-chlorophenyl) piperazine (mCPP), and ocfentanil on surfaces of bags, showing good qualitative and quantitative capabilities. The signal stability was tested with the relative standard deviations better than 20%, and the limits of detection (LODs) and the limits of quantitation (LOQs) for methamphetamine were 0.1 ng/cm² and 0.2 ng/cm², respectively. This method was applied to determine cocaine and methamphetamine in complex matrices (juice, cola, saliva, blood), with the LODs better than 100 μg/L. This method is expected to help expand the application in drug analysis using direct sampling ionization MS analysis. It has potential to be used for fast and on-site testing of various drugs in complicated matrices, such as from ambient surfaces, drinks and biofluids.