Rapid Identification of Unknown Organic Iodine in Small-Volume Complex Biological Samples Based on Nanospray Mass...

A new method for rapid screening of unknown organic iodine (OI) in small-volume complex biological samples was developed using in-tube solid phase microextraction (SPME) nanospray mass spectrometry (MS). The method proposed a new identification scheme for OI based on nanospray high-resolution mass spectrometry (HR-MS). The mass ranges of OI ions were confirmed using the t-MS² scan mode first; then, the possible precursor ions of OI were selected and identified orderly in full MS/ddMS² and t-MS² scan modes. Besides, in-tube SPME was used for the pretreatment of small-volume biological samples, and it was the first time in-tube SPME combined with nanospray MS for OI identification. The whole analysis procedure took only 8 min and consumed 50 μL per sample. Using the new method, six kinds of OI added to urine and an unknown OI C₁₂H₂₃O₁₁I in human milk were successfully identified. Moreover, the proposed identification scheme is also suitable for other ambient mass spectrometry (AMS) to determine unknown compounds with characteristic fragment ions.