In peptide analysis

Hydrazine sulfate is used as a reducing agent in analytical chemistry for gravimetric measurement of nickel, cobalt, and other metals, and in peptide analysis in the separation of polonium from tellurium as an antioxidant in... 

Sample collection and preparation are crucial issues for any bioanalytical application in order to address the complexity of samples originating from biological tissues and fluids. It is necessary to cope with the lack in concentration sensitivity typical for capillary separation techniques, to avoid interference from matrix components as well as to ensure analyte stability. In peptide analysis, a strong focus exists on handling small-volume samples and on selective concentration of the analyte in order to overcome limitations with respect to loadability. In addition, loss of analyte frequently occurs due to degradation by proteases and due to adsorption to surfaces, which accordingly needs to be minimized. 

In peptides analysis, SEC is generally used as a pre-fractionation step to remove high MW molecules such as proteins and polysaccharides. A Sephadex G10 column can be used to separate peptides in two fractions with MW lower and higher than 700 Da (Moreno-Arribas et al., 1998). 

The general status of mass spectrometry in peptide analysis... 

The IMER approach does not require that the enzyme be placed in close proximity to the detector if the transducer signal is generated by a soluble product or cosubstrate of the enzymatic reaction. In the latter case, a variety of flow systems and postreactor detectors can be utilized to produce simultaneous determinations of the concentrations of several analytes. For example, an IMER can be combined with a high-performance liquid chromatography (HPLC) instrument (perhaps also in combination with mass spectroscopy) for purposes of both qualitative and quantitative analysis. The chemo-, stereo-, and regio-selectivities of enzymes facilitate separation and/or identification of analytes that may be present as different isomers (e.g., in peptide analysis based on use of peptidase IMERs in combination with these techniques to obtain structural information about the sequence of amino acids in peptides). 

Janssen, P.S.L. van Nispen, J.W. van Zeeland, M.J.M. Melgers, RA.TA. Complementary information from isotachophoresis and high-performance liquid chromatography in peptide analysis. J.Chromatogr, 1989, 470, 171-183... 

Gronert, S. Huang, R. Li, K.H. Gas phase derivatization in peptide analysis I The utility of trimethyl borate in identifying phosphorylation sites. Int. J. Mass Spectrom. 2004,231, 179-187. 

Lists of useful matrices for FAB are available and their physical and chemical properties have been compiled. In the authors laboratory where FAB is still routinely applied to the analysis of plant secondary metabolites such as saponins, flavonoid glycosides, fatty acid derivatives and small synthetic peptides Mj.< 3000), two matrices are mainly used glycerol, in the analysis of polar hydrophilic compounds and m-nitrobenzylalcohol (m-NBA) for lipophilic compounds. When glycerol is selected the sample is first dissolved in a cosolvent, methanol or a methanol-water mixture, while in the case of m-NBA dichloromethane is employed as cosolvent to facilitate addition of the sample to the matrix. It is a misconception that FAB can only be applied to the analysis of polar analytes lipophilic compounds such as fatty acids and their derivatives are well amenable to FAB analysis if a lipophilic matrix is selected. Other matrices that have often been employed in peptide analysis include thioglycerol and a eutectic mixture of dithiothreitol and dithioerythritol (3 1, w/w), known as magic bullet . For negative ion FAB the basic matrices di- and triethanolamine have also been used. 

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