Direct and rapid characterization of illicit drugs in adulterated samples using thermal desorption electrospray ionization mass spectrometry.

Foods and drinks have been adulterated with illicit drugs to facilitate criminal activities. Unfortunately, conventional analytical methods are incapable of rapidly characterizing these drugs in samples, as serious interferences from sample matrices must be removed through tedious and time-consuming pretreatment. Ambient ionization mass spectrometry (AMS) generally does not require sample pretreatment and is thus a suitable tool for directly and rapidly detecting illicit drugs in samples in different physical states. In this study, thermal desorption electrospray ionization mass spectrometry (TD-ESI/MS), an AMS technique, was utilized to efficiently characterize illicit drugs spiked in samples including drinks, powders, and jelly candies. To perform sensitive analysis, the mass analyzer was operated in multiple reaction monitoring mode to monitor the molecular and fragment ions of the target analytes. The time required to complete a typical TD-ESI/MS analysis was less than 30 s. The limits of detection (LODs) for illicit drugs were found to be 100 ppb in drinks, 100-1000 ppb in instant powders, and 1.3-6.5 ng/mm2 on stamp surfaces. FM2 and nitrazepam laced in the inner layer of a jelly candy were detected by TD-ESI/MS, showcasing the advantage of the technique for direct and rapid analysis as opposed to conventional methods.

Point-of-care identification of organophosphates in gastric juice by ambient mass spectrometry in emergency settings.

BACKGROUND: For emergency management, it is important to promptly identify the organophosphate ingested by self-poisoning patients since different organophosphates cause intoxication through different mechanisms and require different therapeutic strategies. This study aimed at the development of a point-of-care ambient mass spectrometric approach for rapid identification of organophosphate(s) in gastric juice for emergency management. METHODS: Six organophosphate insecticides that are commonly ingested by self-poisoning patients in Taiwan were examined. The sample solutions were prepared and diluted with human gastric juice. A direct metallic probe was dipped and removed immediately from the sample solution. The probe was then inserted into the thermal desorption-electrospray ionization/mass spectrometry (TD-ESI/MS) to detect the analyte on the probe. RESULTS: Since no pretreatment of the specimen was required, the sampling processes followed by thermal desorption-electrospray ionization and mass spectrometric analysis of the organophosphate in the gastric juice were completed within 30 s. The detection limit of the organophosphates is at the 10-100 parts per billion level. Good linearity was observed between the corresponding changes in mass spectrometric signal intensities and the changes of organophosphate concentrations within the range of 5-1000 parts per billion. The high efficiency of this ambient mass spectrometric platform was further confirmed when a real sample of the drained gastric lavage fluid of a patient who suffered from ingestion of chlorpyrifos was collected in the emergency room and tested with this cutting-edge technique. CONCLUSIONS: The results suggested that TD-ESI/MS is promising in promptly providing toxicological information to assist succeeding medical management in an emergency room.