A-cyano-4-hydroxycinnamic acid CHCA

Most commonly used matrix systems are derivatives of benzoic acid (e.g., 2,5-dihydroxybenzoic acid (DHB), derivatives of cinnamic acid (e.g., a-cyano-4-hydroxycinnamic acid (CHCA) or sinapinic acid (SA) (Figure 14.6) as well as heteroaromatic compounds containing nitrogen but numberless other substances and substance classes have been applied as matrices [36]. 

MALDI-MS employs a matrix and the use of a matrix with the samples has several purposes extraction of analyte from the cocrystallization surface, formation of analyte-dropped crystals, and absorption of the laser energy for soft-ionization of analyte molecules into MS analyzer. The commonly used MALDI matrices include a-cyano-4-hydroxycinnamic acid (CHCA), 2,5-Dihydroxybenzoic acid (DHB), Sinapinic acid (SA), et al. [61], A typical matrix solution would comprise the matrix at a concentration of 10-20 mg/mL in a solvent that is compatible with the... 

Peptides/proteins a-Cyano-4-hydroxycinnamic acid CHCA... 

Aminoacridine (9-AA) 2,5-Dihydroxybenzoic acid (DHB), 9-AA a-Cyano-4-hydroxycinnamic acid (CHCA), DHB CHCA, sinapinic acid (SA)... 

Currently, most of the rapid microbial analyses are based on MALDl techniques. Selecting an optimal matrix is a cracial step in developing all of the sample preparation protocols for the MALDI-MS. The MALDl matrices that are frequently used for microbial analysis are a-cyano-4-hydroxycinnamic acid (CHCA), feralic acid (FA), and sinapinic acid (SA). It has been demonstrated that the use of a different matrix for the same kind of sample led to a significant change in the MALDl mass spectrum. For example, the MALDl mass spectra of E. coli obtained with CHCA and a mixture of SA/4-methoxycinnamic acid showed significantly different signals (Demirev et al. 1999). CHCA is one of the most common matrix for bacterial identification. 

Selection of a suitable matrix to analyze a particular lipid class or a category of lipid classes is important for MALDI-MS analysis of lipids and has been well documented [54-57], It is conventional to use a-cyano-4-hydroxycinnamic acid (CHCA) for analysis of lipids in the positive-ion mode while 2,5-dihydroxybenzoic acid (DHB) in the negative-ion mode. Utilization of these matrices results in some of the obstacles for quantitative and global analyses of cellular lipidomes (see Chapter 2). 

MALDI matrix is typically a small organic acid that co-crystallizes with analytes extracted from the tissne section to allow absorption of energy of the pulsed laser. Matrix and analytes are ablated and ionized from the tissne snrfece with subsequent MS analysis. Common matrixes used for the analysis of peptides, lipids, and small drng molecules are 2,5-dihydroxybenzoic acid (DHB) and a-cyano-4-hydroxycinnamic acid (CHCA) while sinapinic acid (S A) is most often used for protein analysis. 1.23,26,27) An organic solvent snch as acetonitrile or methanol can be used for extraction of small molecules from tissne sections prior to matrix co-crystallization. ... 

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