A new algorithm for NMR spectral normalization

There is increasing use of high-resolution NMR spectroscopy to examine vari ations in cell metabolism and/or structure in response to numerous physical , chemical, and biological agents. In these types of studies, in order to o btain relative quantitative information, a comparison between signal intens ities of control samples and treated or exposed ones is often conducted. Th e methods thus far developed for this purpose are not directly related to t he overall intrinsic properties of the samples, but rather to the addition of external substances of known concentrations or to indirect measurement o f internal substances. In this paper, a new method for quantitatively compa ring the spectra of cell samples is presented, It depends on a normalizatio n algorithm which takes into consideration all cell metabolites present in the sample. In particular, the algorithm is based on maximizing, by an oppo rtune sign variable measure, the spectral region in which the two spectra a re superimposed. The algorithm was tested by Monte Carlo simulations as wel l as experimentally by comparing two samples of known contents with the new method and with an older method using a standard, At the end, the algorith m was applied to real spectra of cell samples to show how it could be used to obtain qualitative and quantitative biological information. (C) 1999 Aca demic Press.