Substructure profiling

Substructure profiling by APCl/ESl-MS/MS provides structure specific information useful for analyzing the heterogeneity of glycoconjugated flavor precursors and allows selective localization of hitherto unknown compounds. For example, in... 

G.T. Gray III and C.E. Morris, Influence of Peak Pressure on the Substructure Evolution and Shock Wave Profiles of Ti-6A1-4V, in Sixth World Conference on Titanium (edited by P. Lacombe, R. Tricot, and G. Beranger), Les Editions de Physique, France, 1989, 269 pp. 

The results of theoretical calculation using both general rate and transport-dispersive models were in good agreement with the overloaded band profiles determined experimentally, therefore, the method has been found to be suitable for the prediction of band profiles [88], Natural pigments were generally used as a complicated mixture of various compounds with chromophore substructure. Their separation by preparative RP-HPLC is not necessary, and the application of preparative RP-HPLC for the purification of one or more pigment fractions is not expected in the near future. 

Gillet, V. J., Willett, R, and Bradshaw, J. (1998) Identification of biological activity profiles using substructural analysis and genetic algorithms. J. Chem. Inf. Comput. Sci. 38, 165-179. 

To assist with the MS/MS structure identification, the gross substructure of buspirone is categorized into profile groups (Kerns et al., 1995). Profile groups directly correlate specific product ions and neutral losses with the presence, absence, substitution, and molecular connectivity (Lee et al., 1996) of specific buspirone substructures and their modifications. The profile groups of buspirone are identified with abbreviations that correspond to the three specific substructures azaspirone decane dione (A), butyl piperazine (B), and pyrimidine (P). Substituted substructures are designated with a subscript ( ), and a dash (-) denotes substructure connectivity. Thus, the buspirone molecule is represented by A-B-P. The As-B-P designation... 

Table 6.11 illustrates a representative buspirone metabolite structure database. Information on the structure, molecular weight, UV characteristics, RRT, and product ions of metabolites obtained from rat bile, urine, and liver S9 samples are compiled. Using this format, the predominant buspirone metabolite profile groups, As-B-P, A-B-Ps, and As-B-Ps are easily recognized. These profile groups indicate azaspirone decane dione and pyrimidine as metabolically active sites of attack and the presence of multiple substitution sites on each of these substructures. In many cases, the profile groups indicate the occurrence of metabolic reactions on more than one substructure. 

Volk, K. J. Klohr, S. E. Rourick, R. A. Kerns, E. H. Lee, M. S. 1996. Profiling impurities and degradants of butorphanol tartrate using liquid chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry substructural techniques. J. Pharm. Biomed. Anal., 14,1663-1674. 

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