Rapid drug detection in oral samples by porous silicon assisted laser desorption/ionization mass spectrometry

Abstract

The demand for analysis of oral fluid for illicit drugs has arisen with the increased adoption of roadside testing, particularly in countries where changes in legislation allow random roadside testing of drivers for the presence of a palette of illicit drugs such as methamphetamine (MA), 3,4-methylenedioxymethamphetamine (MDMA) and Delta9-tetrahydrocannabinol (THC). Oral samples are currently tested for such drugs at the roadside using an immunoassay-based commercial test kit. Positive roadside tests are sent for confirmatory laboratory analysis, traditionally by means of gas chromatography/mass spectrometry (GC/MS). We present here an alternative rapid analysis technique, porous silicon assisted laser desorption/ionization time-of-flight mass spectrometry (pSi LDI-MS), for the high-throughput analysis of oral fluids. This technique alleviates the need for sample derivatization, requires only sub-microliter sample volumes and allows fast analysis (of the order of seconds). In this study, the application of the technique is demonstrated with real samples from actual roadside testing. The analysis of oral samples resulted in detection of MA and MDMA with no extraction and analysis of THC after ethyl acetate extraction. We propose that, subject to miniaturization of a suitable mass spectrometer, this technique is well suited to underpin the deployment of oral fluid testing in the clinic, workplace and on the roadside.

Measurement of Illicit Drug Consumption in Small Populations: Prognosis for Noninvasive Drug Testing of Student Populations

“…The data was interpreted to suggest that these three locations had the highest concentration of cocaine users. The successful analysis of drugs on money has prompted the development of analytical methods for the direct analysis of drugs on different surfaces and in different matrices using laser desorption (Lowe et al, 2009) and desorption electrospray ionization (Kauppila et al, 2007).…”

Oral Fluid for The Detection of Drugs of Abuse Using Immunoassay and LC–MS/MS

“…Recent studies indicate that THC-COOH is conjugated and should be hydrolyzed prior to analysis in OF [48][49][50]; many of these analytical methods used GC-MS and derivatization in order to achieve the required sensitivity. LC-MS/MS methods for the analysis of THC and/or THC-COOH in OF include the use of QQQ, linear IT and Q-ToF instruments [19,22,51]. Most methods incorporated deuterium-labeled internal standards and used ESI in positive ion mode, although negative ion approaches have been evaluated [33].…”

Label-Free Porous Silicon Immunosensor for Broad Detection of Opiates in a Blind Clinical Study and Results Comparison to Commercial Analytical Chemistry Techniques

“…Recent work by Lowe et al has successfully combined immunocapture on PSi substrates with laser desorption/ionization mass spectrometry (LDI-MS) techniques to detect drug metabolites in laboratory grade buffer [25] and real-world oral fluid samples [26]. LDI-MS facilitates improved specificity and confirms the identification of captured target molecules, however, in contrast it also adds cost and complexity to the test.…”

“…Oxycodone is a semisynthetic opiate chemically related to morphine and codeine that contains a 6-keto substituent group and a hydroxyl group at carbon 14 [24]. Most commercial opiate immunoassay kits are designed to detect morphine and codeine and have limitations for oxycodone detection [25–30]. Thus oxycodone-specific immunoassays have been developed for use in pain clinics and/or as a secondary opiate screening test in clinical laboratories [27].…”