Direct analysis in real time (DART) and solid-phase microextraction (SPME) transmission mode (TM): a suitable platform for analysis of prohibited substances in small volumes

The reliable and rapid detection of small molecules in challenging sample volumes is of growing interest within the scientific community. In this paper, we document the use of an ambient ionization mass spectrometric (AIMS) technique, DART, coupled with SPME-TM to quantify drugs of abuse in 15 and 25 μL samples of oral fluid (OF) and blood. Combining DART's high detection sensitivity with SPME's pre-concentrating capability allowed us to achieve very low detection limits, with limits of quantitation (LOQs) ranging between 0.5 and 10 ng mL−1 for OF and 2.5 and 25 ng mL−1 for blood. The tested validation points (3, 30, and 90 ng mL−1 for OF; 37.5 and 250 ng mL−1 for blood) provided satisfactory accuracy and repeatability. Additionally, nicotine signals were detected in an OF sample from a male-smoker. Our results demonstrate that DART-MS/MS coupled with SPME-TM can be used as a tool for rapid small-volume analysis.