Ambient ionization mass spectrometry is a technique used for the analysis of samples under ordinary ambient conditions. It has many advantages, such as fast sample exchange, low operation time and few sample preparation which comparing with thus ion source operating in vacuum. Therefore, several different ambient ionization sources have been developed in the past decade. Direct Electrospray Probe ionization mass spectrometry (DEP-MS) was developed by Shiea, J in 1999, which providing an effective means of analyzing not only large biomolecules, but also small organic and inorganic compounds. It can rapidly generate electrospray from a droplet which was deposited on a probe. The DEP technique provides a number of unique analytical features containing: (a) low sample consumption and sample switching is immediate; (b) the capillary and pump are unnecessary; and (c) the probe is low-cost and easy to construct and clean, and is free to maintenance. The first part of experiment in this research is based on the ideal of DEP. The leaf tissues were cut into a triangular shape, 15 mm long and 8 mm wide at the base, is held by a crocodile clip with the apex facing the inlet of the mass spectrometer and at a distance of 2 cm or more from it. Electrospray solutions are added onto the tissue to mix with the leaf sap, and a high voltage (4.5-5.5 kV) is applied to the leaf tissue through the crocodile clip, and generate ions for MS analysis. This method has been demonstrated to be applicable for the analysis of a wide variety of plant sample, such as the leaves tissue in different color, different growth, diseased and pesticide residue. The second part of experiment is improved from the first research. Electrospray was produced via a metal probe which binding two fine stainless steel needle (0.27 mm diameter) together. This probe plays the role of sampling and ionization. An amount of liquid sample was loaded onto the probe when the tip of probe touched the plant tissue, then electropray solution are introduced by syringe pump into the probe and applied high voltage on the probe to produce electrospray ionization. Therefore, direct rapid analysis was achieved using this probe interfaced and this method can direct profile of phytochemicals in a section of plant tissue in different regions, including root, stem, leaf, outer and inner part of fruit. In addition, using this probe, solid samples are directed sampling equally. The solid materials can be observed on the tip of probe by scanning electron microscope (SEM). It can obtain reasonable strong ion signals rapidly for agrochemicals deposited on the surface of vegetables or fruits peel.

A novel ambient ionization method which is so-called direct electrospray probe (DEP) has been developed in this study. This method provides rapid and high throughput analysis due to its advantages such as no sample pretreatment, low sample consumption, easily to change sample. In the study, we improved the interface of direct electrospray probe, and extend spray time to 1 minute for chemical analysis. Because of extending spray time, the method could be combined with principal component analysis (PCA), which is one kind of statistical method. Therefore, we applied the method for determination of alcoholic beverage which contains a lot of ions and alcohol. First, the conditions such as applying voltage, sample volume and shape of probe have been modified. The probes we used in the study were made by used metal pieces. These metal pieces with different thickness and tip angle to be test. Then, we found the optimize conditions as: voltage 7.0 kV, sample volume 3 £gL, thicknss of metal piece 0.1 mm, angle of metal piece 25 degree. Classification of 14 brands of wines which were purchased from supermarket was determined and analyzed by the method. Otherwise, we used the method to distinguish real wines from hedge wines we simulated. The hedge wines were prepared by adding flavor in alcohol solutions. Furthermore, we also used this method to observe fermentation process of wine production. Finally, deterioration of wine under exposure in air was also determined by the method. The results of the study demonstrated that the method we developed can be applied to distinguish hedge wines from real wines. And, it can used to monitor the fermentation process of wine production for quality control.

Ambient mass spectrometry is one of the mainstream techniques in modem mass spectrometry development. The developing purpose of ambient mass spectrometry is improving the analysis efficiency and simplifying operation process. So that, there are many techniques about ambient mass spectrometry had been published and commercialized. And direct electrospray probe mass spectrometry (DEP/MS) is one of ambient mass spectrometry techniques which is emphasized its rapid analysis and high sampling space resolution. In this research we improved the DEP system for more suitable in rapid analysis. We rule of the use of Syringe pump and its tube. Replace it by using solution tank so that we can save the time cost by disassemble syringe pump and tube when sampling. We also change the electric field by different high voltage applied mode for safety concern. In this study DEP/MS were used in plants analysis applications: capsaicin in peppers, systematic pesticide absorption in tomato and toxic compounds distribution in potato surface.