Atmospheric pressure photoionization mass spectrometry

Abstract

I. Introduction and Historical Background 318 II. Short Theoretical Outline 319 A. The Use of a Dopant 319 1. APPI–MS with a Dopant 320 B. Further Parallel Reactions in APPI–MS 321 III. APPI Sources—Overview 321 A. In‐Line Geometry Source 321 B. Orthogonal Geometry Source 323 IV. Factors that Influence the Performance of APPI 323 A. The Dopant 323 B. Mobile Phase Composition 323 V. Applications 324 A. Pharmaceutical and Drug Metabolism 324 1. Non‐Steroidal Compounds 325 2. Steroidal Compounds 327 B. Environmental 327 C. Natural Products 328 D. Synthetic Organics 329 VI. Conclusions 330 Acknowledgments 330 References 330 Atmospheric pressure photoionization (APPI) is the last arrival in the family of atmospheric pressure ionization (API) methods to couple mass spectrometry (MS) to liquid‐phase separation techniques. The basic idea was to further extend the fields of application of liquid chromatography (LC)–MS to those molecules that are not, or are poorly amenable, to electrospray (ESI) or APCI. The present review explores the literature. After a short introduction with an historical background and the premises for its development, we describe the technique, its physical principles, and the factors that affect its efficiency. The review also presents a survey of applications in different fields. © 2003 Wiley Periodicals, Inc., Mass Spec Rev 22:318–331, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mas.10060