Desorption electrospray ionization applications

Z. Takats, J. M. Wiseman and R. G. Cooks, Ambient mass spectrometry using desorption electrospray ionization (DESI) instmmentation, mechanisms and applications in forensics, chemistry, and biology, J. Mass Spectrom., 40, 1261 1275 (2005). 

R. G. Ambient mass spectrometry using desorption electrospray ionization (DESI) instrumentation, mechanisms and applications in forensics, chemistry, and biology. 

Analyses of tropane alkaloids are mainly carried out by GC and HPLC and to a lesser extent by CE. This review describes recent applications developed for the analysis of this class of compounds in plant materials and biological matrices. Of course, mass spectrometry is generally used as the detection technique because of its high sensitivity and selectivity, but other techniques such as UV, fluorescence, flame ionization detection, nuclear magnetic resonance, among others have also been investigated. Finally, desorption electrospray ionization mass spectrometry is reported as a new interesting detection technique for the rapid analysis of samples without any sample preparation. 

One of the most significant developments in mass spectrometry in the recent years is the introduction of a new class of ionization methods where samples in either solid or liquid state can be directly ionized in their native environment under ambient conditions (rather than inside a mass spectrometer) without any sample preparation. This new class of ionization methods is often referred to as ambient ionization methods [1,2], Because these methods generally ionize analytes on the surface or near the surface of the samples at atmospheric pressure, they have also been called atmospheric pressure surface sampling/ionization methods or direct/open air ionization methods [3], Since the first reports on ambient ionization with desorption electrospray ionization (DESI) [4] and direct analysis in real time (DART) [5], numerous reports have been published on the applications of these new ionization methods as well as the introduction of many related ambient ionization methods such as desorption atmospheric pressure chemical ionization (DAPCI) [6], atmospheric solid analysis probe (ASAP) [7], and electrospray-assisted laser desorption/ionization (ELDI) [8], Recently, two reviews of the various established and emerging ambient ionization methods have been published [2,3],... 

A series of technologies has been developed during the last 5 years (with an alphabet soup of acronyms) for the identification of compounds adsorbed on surfaces. The most common methods are desorption electrospray ionization (DESI) (and related techniques) and direct analysis in real time (DART). Applications range from the identification of explosives and drugs in forensics to biological arenas, such as the characterization of tissue sections. 

Takats, Z., Wiseman, J.M., Cooks, R.G. (2005) Ambient Mass Spectrometry Using Desorption Electrospray Ionization (DESI) Instrumentation, Mechanisms and Applications in Forensics, Chemistry, and Biology. J. Mass Spectrom. 40 1261-1275. 

Examples of reports demonstrating development or applications of various TRMS approaches are listed in Table 4.1. The most common interfaces used in TRMS incorporate the following ion sources electrospray ionization (ESI), desorption electrospray ionization... 

In terms of the hardware, TRMS methods described in this book use most common types of ion sources and analyzers. Electrospray ionization (ESI), electron ionization (El), atmospheric pressure chemical ionization (APCI), or photoionization systems, and their modified versions, are all widely used in TRMS measurements. The newly developed atmospheric pressure ionization schemes such as desorption electrospray ionization (DESI) and Venturi easy ambient sonic-spray ionization (V-EASI) have already found applications in this area. Mass analyzers constitute the biggest and the most costly part of MS hardware. Few laboratories can afford purchasing different types of mass spectrometers for use in diverse applications. Therefore, the choice of mass spectrometer for TRMS is not always dictated by the optimum specifications of the instrument but its availability. Fortunately, many real-time measurements can be conducted using different mass analyzers equipped with atmospheric pressure inlets - with better or worse results. For example, triple quadrupole mass spectrometers excel at quantitative capabilities however, in many cases, popular ion trap (IT)-MS instruments can be used instead. On the other hand, applications of TRMS in fundamental studies often require a particular type of instrument (e.g., Fourier transform ion cyclotron resonance mass spectrometer for photodissociation studies on trapped ions). 

It may be that in light of advances made using both desorption electrospray ionization (DESI) [20,21] and direct analysis in real time (DART) [22,23] that the use of IT-SIMS protocols may be supplemented in some applications. These techniques differ in that they sample surface contaminants at atmospheric pressure and do not necessarily require collection of a sample, or transporting the sample into the vacuum environment of the mass spectrometer. However, preliminary experiments have shown that these techniques are tremendously matrix dependent, even more so than SIMS, and thus the generation of even semiquantitative data for environmental surfaces like soil samples remains challenging. Comparisons of ultimate detection limits between the techniques have not yet been accomplished. 

In Chapter 4, titled Principles of Mass Spectrometry Imaging Applicable to Thin-Layer Chromatography, the authors first introduce a budding analytical approach known as imaging mass spectrometry (IMS) strategy and then present some successful examples of its practical applications. Then, they introduce in detail three mass spectrometric techniques as those routinely used within the framework of IMS. These are secondary mass spectrometry (SIMS), matrix-assisted laser desorption/ ionization (MALDI-IMS), and desorption electrospray ionization (DESI). Finally, the authors discuss the advances and bottlenecks of these techniques when applied to TLC. 

Chapter 7, titled Interfacing TLC with Laser-Based Ambient Mass Spectrometry, provides an overview of mass spectrometric techniques that can be coupled with TLC under the most convenient working conditions, that is, at room temperature and atmospheric pressure. The authors introduce readers to electrospray laser desorption ionization (ELDI), plasma-assisted multiwavelength laser desorption/ionization (PAMLDI), laser desorption atmospheric pressure chemical ionization (LD-APCI), laser desorption-dual electrospray and atmospheric pressure chemical ionization I (LD - ESI-I-APCI), laser-induced acoustic desorption electrospray ionization (LIAD-ESI), and laser-induced acoustic desorption-dielectric barrier discharge ionization (LIAD-DBDI). Chapters 6 and 7 are largely complementary because in the former one, main attention is paid to practical applications of a wide number of... 

Desorption electrospray ionization (DESI) was used to obtain mass spectra of dyes, directly from TLC plates. TLC/DESI fundamentals and applications were demonstrated using rhodamines (6G, B, and 123) and federal food, drug, and cosmetic... 

In recent years, TLC was successfully combined with different ionization techniques, matrix-assisted laser desorption/ionization (MALDI), ESI, atmospheric pressure chemical ionization (APCI), desorption electrospray ionization (DESI), electrospray-assisted laser desorption ionization (ELDI), and LDI for identification and quantification of organic and biomolecules. In this section, the interfacing of TLC techniques with MALDI-ESI/MS, DESI-MS, ELSI-MS, and LDI-MS will be described, performance will be discussed, and selected applications in the separation and identification of lipids, gangliosides, dyes, drugs, and medicinal compounds will be presented. 

Law KP (2010) Laser desorption/ionization mass spectrometry on nanostructured semiconductor substrates DIOS (TM) and QuickMass (TM). Int J Mass Spectrom 290 72-84 Law KP, Larkin JR (2011) Recent advances in SALDI-MS techniques and their chemical and bioanalytical applications. Anal Bioanal Chem 399 2597-2622 Lewis WG, Shen Z, Finn MG, Siuzdak G (2003) Desorption/ionization on silicon (DIOS) mass spectrometry background and applications. Int J Mass Spectrom 226 107-116 Li Q, Alonso R, Renner SA, Winefordner JD, Powell DH (2005) Desorption/ionization on porous silicon mass spectrometry studies on pentose-borate complexes. Anal Chem 77 4503-4508 Lin Z, Zhang S, Zhao M, Yang C, Chen D, Zhang X (2008) Rapid screening of clenbuterol in urine samples by desorption electrospray ionization tandem mass spectrometry. Rapid Commun Mass Spectrom 22 1882-1888... 

Pol J, Novak P, Volny M, Kruppa GH, Kostiainen R, Lemr K, Havlicek V (2008) Application of silicon nanowires and indium tin oxide surfaces in desorption electrospray ionization. Eur J Mass Spectrom 14 391-399... 

Weston DJ (2010) Ambient ionization mass spectrometry current understanding of mechanistic theory analytical performance and application areas. Analyst 135 661-668 Wiseman JM, Evans CA, Bowen CL, Kennedy JH (2010) Direct analysis of dried blood spots utilizing desorption electrospray ionization (DESI) mass spectrometry. Analyst 135 720-725... 

Desorption electrospray ionization (DESI) [1] was introduced at the end of 2004, and direct analysis in real time (DART) [2] soon after in 2005. The apparent potential of both DESI and DART in high-throughput applications soon led to the development of some derivatives with the intention to broaden the field of applications or to adapt the underlying methodology to specific analytical needs. Now, the repertoire of methods includes variations of the DESI theme such as desorption sonic spray ionization (DeSSI) [3], later renamed easy sonic spray ionization (EASI) [4] or extractive electrospray ionization (EESI) [5,6]. Then, there are the DESI analogs of APCI and APPI, i.e., desorption atmospheric-pressure chemical ionization (DAPCI) [7,8] and desorption atmospheric pressure photoionization (DAPPI) [9]. 

Recently, it was been shown that an electrospray emitter can be used to provide transla-tionally excited projectiles (charged microdroplets) which serve as projectiles for desorption and ionization of condensed-phase analytes present on surfaces. This hybrid technique, DESI (desorption electrospray ionization), is applicable to analysis of samples in the ambient environment. The practical advantage is that the sample can be examined directly, without any preparation hence the experiment is extremely fast (typically <5 s) and can be conducted in a high-throughput fashion and tandem mass spectrometry can be used for identification of components of complex mixtures. These features provide the speed of analysis and high chemical specificity that are needed in applications such as public safety monitoring. 

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