Ultrahigh-performance liquid chromatography UHPLC

A much more sensitive technique than NMR is MS detection combined with various separation techniques (e.g., high-performance liquid chromatography, HPLC ultrahigh-performance liquid chromatography, UHPLC capillary electrophoresis, CE gas chromatography, GC) that allow previous separation of metabolites. The application of MS enables analysis of large number of metabolites based on their interactions with the separation system and, above all, on the basis of their molecular weights. 

With the advent of fast analytical methods (fast gas chromatography (GC), capillary electrophoresis (CE), ultrahigh performance liquid chromatography (UHPLC)) [27-29], it appears that the extraction methods are the bottleneck for most of the analytical processes. Thus, there is a need for appropriate fast and efficient extractimi steps for plant samples. 

Recendy several studies have reported the use of analytical columns packed with sub-2 pm size particles (11, 12, 14, 15). These columns are especially designed for use with ultrahigh-performance liquid chromatography (UHPLC). The smaller particles are more efficient because they can be used at higher linear velocities, which provides both better resolution and shorter analysis times. UHPLC methods have been reported using isocratic and gradient elutions, a variety of mobile phases, and aqueous buffers with pH ranging from 2.6 to 8.6 to ensure optimum ionization and intensities for specific mass spectrometer ionization sources (14). 

While HPLC has been the standard analytical tool for protein characterization for many years, ultrahigh performance liquid chromatography (UHPLC), sometimes referred to as ultrahigh pressure liquid chromatography, has the potential to increase resolution and efficiency compared to conventional HPLC and, thus, facilitate improved protein characterization. Like conventional HPLC, UHPLC can provide... 

Most frequently, high-pressure liquid chromatography (HPLC) is used in LC-MS work, while more recently ultrahigh-pressure liquid chromatography (UHPLC or ultra performance liquid chromatography, UPLC, as it is termed by one manufacturer) has come into use. For very low saiiple amounts, nanoLC, i.e., capillary LC, can directly be interfaced to nanoESI. 

In another study, a selective, rapid, and sensitive 12.7-min ultrahigh performance liquid chromatography-isotope dilution tandem mass spectrometry (UHPLC— ID-MS/MS) method was developed and compared to a conventional 74-min... 

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