Development of Electrospray/Photoionization Miniature Ion Trap Mass Spectrometer

An electrospray/ultraviolet lamp dual-source ion trap mass spectrometer was developed for the rapid detection of gas and liquid samples. A discontinuous atmospheric pressure sampling system was used in the instrument, in which both the electrospray ions and gaseous analytes were sampled and transferred by a pinch valve device. The two ionization sources used here were generally suitable for different kinds of analytes and provide complementary applications. Electrospray was used for the ionization of polar compounds in solution, while the UV ionization source was mainly applied to the analysis of gaseous organic compounds. A variety of samples such as anisole, toluene, 2,4-dimethylaniline, arginine, reserpine and aspartame were employed to test the performance in different working mode of the instrument. The result showed that the two sources was suitable for ionization of different samples, and different types of molecular ions were generated when analyzing 2,4-dimethylaniline. Two ionization sources could be used alternately or simultaneously without interference with the other and the working mode could also be switched to fit the application requirements. Dual-source configuration was an effective way to extend the applications for miniature mass spectrometers. It did not significantly increase the size of the instrument, but provided more versatile analysis to meet the need for the measurement of different types of samples.