Using ambient mass spectrometry and LC-MS/MS for the rapid detection and identification of multiple illicit street drugs
Chien-Hua Chiang a, Hei-Hwa Lee b, Bai-Hsiun Chen b, Yi-Ching Lin b, Yu-Ying Chao c,**, Yeou-Lih Huang a,b,d,*
a Department of Medical Laboratory Science and Biotechnology, College of Health Sciences, Kaohsiung Medical
University, Kaohsiung, Taiwan
b Department of Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
c Department of Public Health, College of Health Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan
d Department of Chemistry, National Sun Yat-sen University, Kaohsiung, Taiwan
In this study the recently developed technique of thermal desorption electrospray ionization/ mass spectrometry (TD-ESI/MS) was applied to the rapid analysis of multiple controlled substances. With the reallocation of mass spectral resources [from a standard ESI source coupled with liquid chromatography (LC) to an ambient TD-ESI source], this direct-analysis technique allows the identification of a wider range of illicit drugs through a dual-working mode (pretreatment-free qualitative screening/conventional quantitative confirmation). Through 60-MRM (multiple reaction monitoring) analysis-in which the MS/ MS process was programmed to sequentially scan 60 precursor ion/product ion transitions and, thereby, identify 30 compounds (two precursor/product ion transitions per compound) of a four-component (drug) standard, the signal intensity ratios of each drug transition were comparable with those obtained through 8-MRM analysis, demonstrating the selectivity of TD-ESI/MS for the detection of multiple drugs. The consecutive analyses of tablets containing different active components occurred with no cross-contamination or interference from sample to sample, demonstrating the reliability of the TD-ESI/MS technique for rapid sampling (two samples min-1). The active ingredients in seized drug materials could be detected even when they represented less than 2 mg g-1 of the total sample weight, demonstrating the sensitivity of TD-ESI/MS. Combining the ability to rapidly identify multiple drugs with the “plug-and-play” design of the interchangeable ion source, TD-ESI/MS has great potential for use as a pretreatment-free qualitative screening tool for laboratories currently using LC-MS/MS techniques to analyze illicit drugs.
Keywords: Ambient mass spectrometry, Illicit drug, Thermal desorption