Hyphenated High-Pressure Liquid

Hyphenated High-Pressure Liquid Chromatography (KPLC) NMR-MS Techniques for Automatization and Microscaie Anaiysis... 

Mass spectrometry (MS) is probably a famhiar tool to chemistry and biology students as a technique commonly used to measure the molecular mass of a sample. Often, MS is used in tandem with other techniques for chromatic separation of the sample before mass measurement. Some common hyphenated techniques include HPLC-MS, high-pressure liquid chromatography coupled to MS GC-MS, gas chromatography coupled to MS or CE-MS, capillary electrophoresis coupled to MS. 

Hyphenated TLC techniques. TLC has been coupled with other instrumental techniques to aid in the detection, qualitative identification and, occasionally, quantitation of separated samples, and these include the coupling of TLC with high-pressure liquid chromatography (HPLC/TLC), with Fourier transform infra-red (TLC/FTIR), with mass spectrometry (TLC/ MS), with nuclear magnetic resonance (TLC/NMR) and with Raman spectroscopy (TLC/RS). These techniques have been extensively reviewed by Busch (1996) and by Somsen, Morden and Wilson (1995). The chemistry of oils and fats and their TLC separation has been so well established that they seldom necessitate the use of these coupling techniques for their identification, although these techniques have been used for phospholipid detection. Kushi and Handa (1985) have used TLC in combination with secondary ion mass spectrometry for the analysis of lipids. Fast atom bombardment (FAB) has been used to detect the molecular species of phosphatidylcholine on silica based on the molecular ion obtained by mass spectrometry (Busch et al, 1990). 

Michel T, Destandau E, Elfakir C (2011) On-line hyphenation of centrifugal partition chromatography and high pressure liquid chromatography for the fractionation of flavonoids from Hippophae rhamnoides L. berries. J Chromatogr A 1218 6173-6178... 

The development of hyphenated techniques for rapid separation of mixtures and spectroscopic analysis of its components is a topic of great interest, particularly when the amount of sample is limited and the need for automatization is high. This is the case for high-pressure liquid chromatography nuclear magnetic resonance-mass spectroscopy (HPLC NMR-MS), which has been shown to be extremely useful in certain pharmaceutical and medical applications. 

There are different approaches to the hyphenation of HPLC with MS and some commercial interfaces are available. Atmospheric pressure ionization (API), a soft and highly efficient method suitable for analysis of polar, ionic, high-molecular-mass, and thermally labile compounds amenable to LC has greatly increased the popularity of LC-MS. API-based interfacing systems are ES and ISP, which are liquid-based interfaces. 

---