Sonic spray ionization

A detailed description of sources used in atmospheric pressure ionization by electrospray or chemical ionization has been compiled.2 Atmospheric pressure has been used in a wide array of applications with electron impact, chemical ionization, pressure spray ionization (ionization when the electrode is below the threshold for corona discharge), electrospray ionization, and sonic spray ionization.3 Interferences potentially include overlap of ions of about the same mass-charge ratio, mobile-phase components, formation of adducts such as alkali metal ions, and suppression of ionization by substances more easily ionized than the analyte.4 A number of applications of mass spectroscopy are given in subsequent chapters. However, this section will serve as a brief synopsis, focusing on key techniques. 

A home-built spray ion source, operable in both the sonic-spray ionization (SSI) and electrospray ionization (ESI) modes, was used instead of the standard ESI source of the Einnigan LCQ instrument. (Erom Takats et al., 2003b)... 

Takats, Z. Nanita, S. C. Cooks, R. G. Schlosser, G. Vekey, K. Amino Acid Clusters Formed by Sonic Spray Ionization. Anal Chem. 2003a, 75, 1514-1523. 

The real breakthrough in LC/MS development was achieved with the broad introduction in the 1990s of atmospheric pressure ionization (API) techniques, such as electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI), which enable the analysis of a wide variety of molecular species. The spectrum of available API techniques has been amended meanwhile by the introduction of sonic spray ionization (SSI) and atmospheric pressure photoionization (APPI). 

Kanazawa et al. [124] determined omeprazole and its metabolites in human plasma by liquid chromatography-three-dimensional quadrupole mass spectrometry with a sonic spray ionization interface. The analytical column was YMC-Pack Pro Cig (5 cm x 2 mm) using acetonitrile-50 mM ammonium acetate (pH 7.25) (1 4) at a flow-rate of 0.2 ml/min. The drift voltage was 30 V. The sampling aperture was heated at 110 °C and shield temperature was 230 °C. In the mass spectrum, the molecular ions of omeprazole, hydroxyomeprazole, and omeprazole sulfone were clearly observed as base peaks. The method is sufficiently sensitive and accurate for pharmacokinetic studies of omeprazole. 

Gardner, J. S., Harrison, R. G., Lamb, J. D., Dearden, D. V., Sonic spray ionization mass spectrometry a powerful tool used to characterize fragile metal-assembled cages. New]. Chem. 2006, 30, 1276-1281. 

LLE liquid-liquid extraction, SPE solid phase extraction, LPME liquid-phase microextraction, ESI electrospray ionization, APCI atmospheric pressure chemical ionization, SSI sonic spray ionization, Q quadrupole, QqQ triple quadrupole, TOF time-of-flight, IT ion trap, IS internal standard, CV coefficient of variation, MRE mean relative error, LOD limit of detection, LLOQ lower limit of quantification... 

A. Hirabayashi, M. Sakairi, H. Koizumi, Sonic spray ionization method for API-MS,... 

K.A. Mortier, R. Dams, W.E. Lambert, E.A. De Letter, S. Van Calenbergh, A.P. De Leenheer, Determination of paramethoxyamphetamine and other amphetamine-related designer drugs by LC-sonic spray ionization MS, Rapid Commun. Mass Spectrom., 16 (2002) 865. 

Several ionization methods have been applied for CE-MS couphng. Matrix-assisted laser desorption ionization (MALDI), continuous flow fast atom bombardment (FAB), laser vaporization ionization with UV laser, sonic spray ionization and electrospray ionization (ESI) have all been used for coupling CE to MS. However, ESI is now undoubtedly the most widely used ionization technique, employing numerous analyzers including quadrupoles, magnetic sector, Fourier transform ion cyclotron resonance, time-offlight and trapping devices. However, quad-rupole detectors have predominantly been applied in CE-MS [6-8]. 

Hirabayashi, A. Sakairi, M. Koizumi, H. Sonic spray ionization method for atmospheric-pressure ionization mass-spectrometry. Anal. Chem. 1994,66,4557-4559. 

Figure 2,14 Illustration of the V-EASI dual mode of operation (a) V EASI performed for a 30 ng mt sildenaphil solution in acidified methanol and (b) V -EASI performed for a commercial sildenaphil tablet using acidified methanol as the spray solvent [ 104], Reproduced with permission from Santos, VC., Regiani, T., Dias, F.F.C., Romao, W., Jara, J.L.P., Klitzke, C.F., Coelho, F, Eberlins, M.N. (2011) Venturi Easy Ambient Sonic-Spray Ionization. Anal. Chem. 83 1375-1380. Copyright (2011) American Chemical Society...

Santos, V.G., Regiani, T, Dias, F.F.G., Romao, W, Jara, J.L.P., Klitzke, C.F, Coelho, F, Eberlins, M.N. (2011) Venturi Easy Ambient Sonic-Spray Ionization. Anal. Chem. 83 1375-1380. 

Hu, J.-B., Chen, T.-R., Chang, C.-H., Cheng, J.-Y., Chen, Y.-C., Urban, P.L. (2015) A Compact 3D-Printed Interface for Coupling Open Digital Microchips with Venturi Easy Ambient Sonic-Spray Ionization Mass Spectrometry. Analyst 140 1495-1501. 

Cl, chemical Ionization EESI, electrosonic spray Ionization El, electron ionization ICR, ion cyclotron resonance OIT, orbital Ion trap QqQ, triple quadrupole S, seaor SALDI, surface-assisted laser desorptlon/lonizatlon V-EASI, Venturi easy ambient sonic-spray ionization, n.d.. No data. 

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). 

EASI easy ambient sonic-spray ionization... 

In 2008, easy ambient sonic-spray ionization mass spectrometry (EASI-MS), originally named desorption sonic spray ionization (DeSSI), was coupled with TLC [69], later with HPTLC [70]. An acidic mixture of methanol and water was sprayed at a maximum flow rate of 15 pL/min coaxial with the supersonic nebulizing gas set at 30 bar. The spray beam of the homemade easy ambient sonic-spray ionization (EASI) source was mounted on the supplied nano-electrospray ionization (nano-ESI) source and directed in a 30-degree angle onto the plate. Without any voltage or heating, just the impact of a high velocity spray served to extract and desorb analytes from the TLC surface and softly ionize them. 

Haddad, R., Milagre, H.M.S., Catharine, R.R., Eberlin, M.N. (2008) Easy ambient sonic-spray ionization mass spectrometry combined with thin-layer chromatography. Analytical Chemistry, 80,2744-2750. 

Eberlin, L.S., Abdelnur, P.V., Passero, A., de Sa, G.F., Daroda, R.J., de Souza, V, Eberlin, M.N. (2009) Analysis of biodiesel and biodiesel-petrodiesel blends by high performance thin layer chromatography combined with easy ambient sonic-spray ionization mass spectrometry. Analyst, 134,1652-1657. 

---