Rapid, Direct Analysis of Cholesterol by Charge Labeling in Reactive Desorption Electrospray Ionization

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• 作者：Chunping Wu ; Demian R. Ifa ; Nicholas E. Manicke ; R. Graham Cooks
• 刊名：Analytical Chemistry
• 出版年：2009
• 出版时间：September 15, 2009
• 年：2009
• 卷：81
• 期：18
• 页码：7618-7624
• 全文大小：238K
• 年卷期：v.81,no.18(September 15, 2009)
• ISSN：1520-6882

文摘

Direct and rapid analysis of cholesterol was accomplished in the ambient environment using reactive desorption electrospray ionization (DESI) mass spectrometry. This was achieved by electrospraying reagent solutions in the form of high velocity charged droplets at surfaces such as dried serum samples and animal tissue sections. Betaine aldehyde, incorporated into the spray solvent, reacts selectively and rapidly with the alcohol group of cholesterol by nucleophilic addition, forming a hemiacetal salt. Limits of detection for pure cholesterol and related compounds were 1 ng when a solution of cholesterol of 1 μg/mL was spotted onto the surface. Quantitative analysis of free cholesterol in serum using reactive DESI was demonstrated using cholesterol-d7 as internal standard. High throughput analysis of small volumes of serum spotted onto a suitable substrate was achieved at an analysis rate of 14 s per sample, with a relative standard deviation (RSD) of ca. 6%. Use of reactive DESI in the imaging mode allowed 2D spatial distributions of phospholipids and cholesterol to be recorded simultaneously in rat brain tissues.