The advantages of ESI‐MS detection in conjunction with HILIC mode separations: Fundamentals and applications

Abstract

The analysis of highly hydrophilic, ionic, and polar compounds has been performed by HILIC-ESI-MS for the last few years. The use of low aqueous/high polar organic solvent content in HILIC separation mobile phase is almost ideal for ESI-MS detection in many cases, resulting in increased sensitivity. Although the addition of modifiers such as acids or salts is necessary in some circumstances for a good separation, the optimum concentrations used are still highly amenable for ESI-MS analysis, showing few deleterious effects. In this review, the mechanism of HILIC separation and ESI ion generation will be briefly discussed, followed by a summary of method development and applications in several fields of research including pharmaceutical, biomolecular, food, metabolic, and environmental analysis.

Elemental ratio measurements of organic compounds using aerosol mass spectrometry: characterization, improved calibration, and implications

“…These include combustion analysis (O'Brien et al, 1975;Krivacsy et al, 2001;Kiss et al, 2002), electrospray ionization coupled to ultra-high-resolution mass spectrometry with (ESI) (Nguyen and Schug, 2008;Altieri et al, 2009;Bateman et al, 2009;Kroll et al, 2011;Mazzoleni et al, 2010), nuclear magnetic resonance (NMR) spectroscopy (Fuzzi et al, 2001), Fourier transform infrared spectroscopy (FTIR) (Gilardoni et al, 2009;Mysak et al, 2011), and X-ray photoelectron spectroscopy (XPS) . Gas chromatography-mass spectrometry (GC-MS) (Williams et al, 2006) and chemical ionization mass spectrometry (CIMS) with aerosol collection interface have also recently been coupled to a high-resolution time-of-flight mass spectrometer to allow for determination of elemental ratios (i.e., O : C and H : C) of organic aerosols (LopezHilfiker et al, 2014;Yatavelli and Thornton, 2010;Williams et al, 2014).…”

Metabolomic Analysis of Schizosaccharomyces pombe: Sample Preparation, Detection, and Data Interpretation

“…This protocol is suitable for simultaneous measurement and identification of hundreds of polar metabolites (including ATP), and provides good long-term stability and reproducibility. (We have used it for over 7 yr.) The benefits of HILIC separation combined with MS detection have been reviewed in detail by Nguyen and Schug (2008). It should be noted, though, that complementary approaches using different LC-MS (Zhou et al 2012), GC-MS (Garcia and Barbas 2011), or CE-MS (Ramautar et al 2009) methods are available, and the decision to apply a particular technology should be based on its applicability to target molecules and on the instrumentation available to the researcher, as well as the researcher's expertise in its use.…”

Quantification of Glucuronide Metabolites in Biological Matrices by LC-MS/MS

“…For example, a successful application of HILIC mechanism for morphine glucuronides separation and ionization has been described more than a decade ago (Naidong, Lee et al 1999). The retention mechanism in underivatized silica is not only hydrophilic, but also hydrophobic and ion-exchange, which may cause a mixed-mode retention, and is sometimes difficult to predict (Nguyen and Schug 2008). In derivatized silica with a zwitterionic bonded phase (commercially known as ZIC-HILIC), there is no ion-exchange mechanism of retention (the zwitterions in stationary phase cancel each other out and there is no net charge of ion-exchange (Ahuja and Dong 2005)).…”