US-SOMO HPLC-SAXS module: Dealing with capillary fouling and extraction of pure component patterns from poorly resolved SEC-SAXS data

Emre Brookes, Patrice Vachette, Mattia Rocco, Javier Pérez

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74 Scopus citations


Size-exclusion chromatography coupled with SAXS (small-Angle X-ray scattering), often performed using a flow-Through capillary, should allow direct collection of monodisperse sample data. However, capillary fouling issues and non-baseline-resolved peaks can hamper its efficacy. The UltraScan solution modeler (US-SOMO) HPLC-SAXS (high-performance liquid chromatography coupled with SAXS) module provides a comprehensive framework to analyze such data, starting with a simple linear baseline correction and symmetrical Gaussian decomposition tools [Brookes, Pérez, Cardinali, Profumo, Vachette & Rocco (2013). J. Appl. Cryst.46, 1823-1833]. In addition to several new features, substantial improvements to both routines have now been implemented, comprising the evaluation of outcomes by advanced statistical tools. The novel integral baseline-correction procedure is based on the more sound assumption that the effect of capillary fouling on scattering increases monotonically with the intensity scattered by the material within the X-ray beam. Overlapping peaks, often skewed because of sample interaction with the column matrix, can now be accurately decomposed using non-symmetrical modified Gaussian functions. As an example, the case of a polydisperse solution of aldolase is analyzed: from heavily convoluted peaks, individual SAXS profiles of tetramers, octamers and dodecamers are extracted and reliably modeled.The US-SOMO HPLC-SAXS (high-performance liquid chromatography coupled with small-Angle X-ray scattering) module is an advanced tool for the comprehensive analysis of SEC-SAXS (size-exclusion chromatography coupled with SAXS) data. It includes baseline and band-broadening correction routines, and Gaussian decomposition of overlapping skewed peaks into pure components.

Original languageEnglish
Pages (from-to)1827-1841
Number of pages15
JournalJournal of Applied Crystallography
Issue number5
StatePublished - Oct 1 2016


  • CorMap analysis
  • P-value analysis
  • US-SOMO HPLC-SAXS module
  • aldolase supramolecular complexes
  • asymmetric modified Gaussian decomposition
  • multi-resolution modeling
  • poorly resolved chromatographic peaks


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