Atmospheric Pressure Photoionization for Ionization of Both Polar and Nonpolar Compounds in Reversed-Phase LC/MS
详细信息 查看全文
- 作者：Damon B. Robb ; Michael W. Blades
- 刊名：Analytical Chemistry
- 出版年：2006
- 出版时间：December 1, 2006
- 年：2006
- 卷：78
- 期：23
- 页码：8162 - 8164
- 全文大小：110K
- 年卷期：v.78,no.23(December 1, 2006)
- ISSN：1520-6882
文摘
Atmospheric pressure photoionization can provide highionization efficiency simultaneously to both polar andnonpolar compounds delivered in reversed-phase solvent.The method to achieve this utilizes toluene as a dopantand simply requires that the solvent flow be limited sothat reactions between toluene photoions and the organiccomponent of the solvent are not driven to completion.Under these conditions, toluene photoions remain in thesource for ionizing nonpolar compounds via charge exchange (electron transfer), while protonated solvent ionsare available for proton-transfer reactions with polarmolecules. The reagent ion mixture is then suitable forionizing a wide range of both polar and nonpolar compounds. The critical effect of solvent flow rate is demonstrated here with results for a test analyte, 9-methylanthracene, which may be ionized by either charge exchangeor proton transfer. For a solvent of 50:50 methanol/water(v/v), lowering the flow from 200 to 50 
L min-1 resultsin a 10× increase in charge exchange ionization efficiency-further flow reductions provide even greater enhancements. This method is compatible with sample deliveryby direct infusion and micro- and narrow-bore LC, as wellas conventional LC using a flow splitter.
L min-1 resultsin a 10× increase in charge exchange ionization efficiency-further flow reductions provide even greater enhancements. This method is compatible with sample deliveryby direct infusion and micro- and narrow-bore LC, as wellas conventional LC using a flow splitter.