Non-Proximate Detection of Small and Large Molecules by Desorption Electrospray Ionization and Desorption Atmospheric Pressure Chemical Ionization Mass Spectrometry: Instrumentation and Applications i

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• 作者：Ismael Cotte-Rodrí ; guez ; Christopher C. Mulligan ; R. Graham Cooks
• 刊名：Analytical Chemistry
• 出版年：2007
• 出版时间：September 15, 2007
• 年：2007
• 卷：79
• 期：18
• 页码：7069 - 7077
• 全文大小：250K
• 年卷期：v.79,no.18(September 15, 2007)
• ISSN：1520-6882

文摘

Ambient surfaces are examined by mass spectrometry atdistances of up to 3 m from the instrument without anyprior sample preparation. Non-proximate versions of thedesorption electrospray ionization (DESI) and desorptionatmospheric pressure chemical ionization experimentsare shown to allow rapid, sensitive, and selective detectionof trace amounts of active ingredients in pharmaceuticaldrug formulations, illicit drugs (methamphetamine, cocaine, and diacetylmorphine), organic salts, peptides,chemical warfare agent simulants, and other small organiccompounds. Utilizing an ion transport tube to transportanalyte ions to the mass spectrometer, nonproximateDESI allows one to collect high-quality, largely interference-free spectra with signal-to-noise (S/N) ratios of morethan 100. High selectivity is achieved by tandem massspectrometry and by reactive DESI, a variant experimentin which reagents added into the solvent spray allow bond-forming reactions with the analyte. Ion/molecule reactionswere found to selectively suppress the response of mixturecomponents other than the analyte of interest in nonproximate-DESI. Flexible ion transport tubing is also investigated, allowing performance similar to stainless steeltubing in the transport of ions from the sample to the massspectrometer. Transfer tube temperature effects are examined. A multiple sprayer DESI source capable ofanalyzing a larger sample area was evaluated to decreasethe sampling time and increase sample throughput. Lownanogram detection limits were obtained for the compounds studied from a wide variety of surfaces, even thosepresent in complex matrixes.