Monoisotopic molecular weight

Monoisotopic molecular weight The molecular weight of an analyte, calculated by using the masses of the more/most abundant isotopes of each of the elements present. 

This screening experiment yielded the monochlorinated DHFR ligand 1 at m/z 515.24, corresponding to an [M+H]+ ion with a monoisotopic molecular weight of 514.23 amu. No signal for this ion was evident in an ALIS control experiment with DHFR in the absence of the screening library (Fig. 3.5). Table 3.1 shows a... 

Exact mass is defined as the monoisotopic molecular weight of a molecule and is calculated using the mass of the most abundant isotope of each element. 

Figure 12.6. Top Structures of SCH 226374 and SA with monoisotopic molecular weights. Bottom Standards run on Voyager STR in reflectron mode, (a) SA with added NaH2P04. (b) SCH 226374, 5 pmol on plate, with applied SA. The presence of 13C and 37Cl isotope signals at m/z 696.41 and 697.41 confirms the presence of the drug (Reprinted with permission from Reyzer et al., 2003).

Nevertheless, reliable methods using the SIM mode were introduced for TA analysis. The SIM mode was used for analysis of atropine and scopolamine from human viscera [15] and human plasma [11] (Table 8), of tropisetron from liver microsomal incubation mixtures [82] (Table 7), of granisetron from rat plasma [72], of hyoscyamine enantiomers from human plasma [48], of scopolamine from rabbit plasma [89], of tiotropium from human plasma [81] (Table 5) and of atropine from dog plasma [96] (Table 6). The corresponding values for the monoisotopic molecular weight (MW) and the corresponding m/z-val ucs of protonated TTA and pure QTA are summarized in Table 9. 

Fig. 10.8 ESI-FT-ICR mass spectrum of bovine tions of the 6- and 12-fold protonated ions ubiquitin. A sample solution of ca. 0.01 mg ml (monoisotopic molecular weight, determined in 3 % aqueous acetic acid methanol (4 1) was 8559,5912 calculated 8559,6152 A m 3 ppm), employed. The inserts show isotopic separa-...

Combining the information present in each type of CID spectrum made the determination of the complete sequences of some peptides possible, e.g., the peptide at m/z 1957.06 (theoretical monoisotopic molecular weight for the sequence EIIIYQPTGNPNQQWR [M-t-H]+ 1956.99 Da observed mass 1957.06 Da mass accuracy +0.07 Da). 

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