| Summary: | 碩士 === 國立臺灣師範大學 === 化學系 === 103 === A novel and highly sensitivity electrospray ionization method, nib spray-mass spectrometry (NS-MS), is described. A bamboo pen nib was shaped and used for sample loading and ionization. The nib can be directly connected to ESI ion sources of various mass spectrometers. The sample solution can be loaded onto the nib by normal pipetting. The sample solution slips into the seam (width, ~7.5 µm) of the nib by capillary attraction. Meanwhile, the seam functions as a micro reservoir and prevents the sample solution from spreading to the surface. When a high voltage is applied to the nib, the sample solution is rapidly ejected and ionized toward the mass inlet. Since ionization occurs within a very short period, an abundance of ions is formed, leading to a dramatic improvement in the limit of detection. Using para-chloroamphetamine as a model compound, the limit of detection was determined to be 10 ng/mL. In contrast to this, when the traditional methods were used, including paper-spray and wooden tip-spray, the limits of detection were 100 and 50 ng/mL, respectively. Detailed information on how to make a bamboo pen nib, the optimized position for ionization, the detection of kinds of designer drugs and its application for the analysis of a saliva sample are also reported.
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