title: Guinier peak analysis for visual and automated inspection of small-angle X-ray scattering data.
abstract: The Guinier region in small-angle X-ray scattering (SAXS) defines the radius of gyration,Rg, and the forward scattering intensity,I(0). In Guinier peak analysis (GPA), the plot ofqI(q)versus q2transforms the Guinier region into a characteristic peak for visual and automated inspection of data. Deviations of the peak position from the theoretical position in dimensionless GPA plots can suggest parameter errors, problematic low-resolution data, some kinds of intermolecular interactions or elongated scatters. To facilitate automated analysis by GPA, the elongation ratio (ER), which is the ratio of the areas in the pair-distribution functionP(r) after and before theP(r) maximum, was characterized; symmetric samples have ER values around 1, and samples with ER values greater than 5 tend to be outliers in GPA analysis. Use of GPA+ER can be a helpful addition to SAXS data analysis pipelines.
authors.affiliation: Ludwig Institute for Cancer Research , Department of Medicine, University of California School of Medicine, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0669, USA.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Putnam
keywords: Guinier analysis; Guinier peak analysis; elongation ratio; sample characterization; small-angle X-ray scattering