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

Abstract

BackgroundFor 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. MethodsSix 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. ResultsSince 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. ConclusionsThe results suggested that TD-ESI/MS is promising in promptly providing toxicological information to assist succeeding medical management in an emergency room.