Nanoelectrospray Ionization High-Field Asymmetric Waveform Ion mobility Spectrometry with Q-TOF mass spectrometry for Identification of Nitrosamines in Water

摘要

Trace levels of N-nitrosodimethylamine (NDMA) have been detected in source water and finished drinking water. Because of its carcinogenicity, monitoring of NDMA and related nitrosamines in drinking water becomes an important public health issue. Nitrosamines have relatively low molecular weights and are highly hydrophilic. In addition, other molecules with similar chemical and physical properties often present in water samples. Determination and identification of trace levels of nitrosamines in water is an analytical challenge. Here, we report a new technique through integration of nanoelectrospray ionization and high-field asymmetric waveform ion mobility spectrometry with quadrupole time-of-flight (Q-TOF) mass spectrometry (nanoESI-FAIMS-MS) for identification of nitrosamines in water. A number of important features of this technique are demonstrated in this study. The nanoESI technique provides introduction of small amounts of analytes in microL volumes of samples with high efficient ionization, while the FAIMS provides high efficient separation of ions transferred from water samples into the gas phase under atmospheric pressure and room temperature. This unique feature allows the separation of molecular species that are difficult to separate by gas or liquid chromatography. It is compatible with other mass spectrometers. The FAIMS separation of gas phase ions can greatly reduce the chemical background and interference.