NanoLC-ESI

Pinkse, M.W., Uitto, P.M., Hilhorst, M.J., Ooms, B., Heck, A.J. (2004).. Selective isolation at the femtomole level of phosphopeptides from proteolytic digests using 2D-NanoLC-ESI-MS/MS and titanium oxide precolumns. Anal. Chem. 76, 3935-3943. 

Use these solutions directly for MALDI-MS and nanoLC-ESI-MS or desalt them... 

NanoLC-ESI-MS of tryptically digested human IgG. Extracted chromatograms for the two main diagnostic glycan ions, HexHexNAc m/z 366 upper panei) and HexNAc m/z 204 lower panel) are shown. The chromatograms of both ions indicate that most of the glycopeptides elute between 10 and 18 minutes... 

NanoLC-ESI-MS of tryptically digested human IgG. The extracted chromatogram of the ion at m/z 1479 shows a signal at 15 minutes (upper panel). The lower panel shows the summation of all spectra acquired between 14 and 16 min. The resulting MS spectrum demonstrates the presence of several glycoforms of the peptide EEQYNSTYR. Monosaccharide symbols are shown in O Table 1... 

Magnified views of the nanoLC-ESI-MS/MS of the glycopeptide signal at m/z 13982. The b- and y-ions were used to sequence the peptide (summarised in top panel)... 

In order to meaningfully compare MALDI detection limits to the other techniques, specifically defined analytical conditions must be established. The case of peptide mapping is a good starting point because this class of chemical species ionizes well using both MALDI and ESI. Moreover, a relatively large body of work using both NanoLC/ESI and NanoLC/MALDI has been reported from which some initial conclusions may be drawn. As... 

Separation and detection techniques for antibacterials in food mainly focus on the use of LC coupled to MS or tandem MS. Nevertheless, recent studies have suggested capillary electrophoresis coupled to laser-induced fluorescence (LIE) as a way of improving sensitivity [49], HRLC coupled to microTOF-ESI-MS as a highly selective, sensitive, and quick screening method for 100 veterinary drugs in fish, meat, and egg samples [195], and nanoscale LC coupled to UV or ion trap MS, with LODs in the range 0.01-0.51 pg/L (nanoLC-MS) and the possibility that even lower limits could be achieved by using triple quadrupole MS [59]. 

Developments in mass spectrometry technology, together with the availability of extensive DNA and protein sequence databases and software tools for data mining, has made possible rapid and sensitive mass spectrometry-based procedures for protein identification. Two basic types of mass spectrometers are commonly used for this purpose Matrix-assisted laser desorption/ionization (MALDI)-time-of-flight (TOF) mass spectrometry (MS) and electrospray ionization (ESI)-MS. MALDI-TOF instruments are now quite common in biochemistry laboratories and are very simple to use, requiring no special training. ESI instruments, usually coupled to capillary/nanoLC systems, are more complex and require expert operators. We will therefore focus on the use of MALDI-... 

Fourier transform Ion cyclotron resonance ESI, APCl, MALDl, E1,C1 0.1-5 >1,500,000 -250,000 Very high resolution, high-accuracy m/z analysis LC/MS, nanoLC/MS, and MALDl... 

As highlighted in the reviews from Li et al. [71] and Hummon et al. [41], in addition to the mollusk single-cell models, MALDI-MS associated or not to nanoLC and on-line LC-ESI-MS/MS has been successfully applied to a wide variety of animal species from invertebrates to vertebrates. 

As ESI works on a continuous flow of liquid, it has quickly been coupled to LC or other liquid-phase separation techniques as an alternative to optical detection.15 Mass spectrometry gives more information on the eluted compound, and the resulting hyphenated technique enables one to decrease the complexity of samples before their analysis by MS. High performance liquid chromatography (HPLC) is coupled to conventional ESI-MS while nanoLC is connected to nanoESI-MS for a better match in the flow-rate values. 

Figure 3.7 First coupling of a nanoLC column to the ESI Chip using a liquid electrode to apply spray voltage to the effluent exiting a capillary positioned at the inlet to the ESI Chip. Make-up flow was optionally applied to adjust solvent composition to enhance ionization.

---