US‐SOMO HPLC‐SAXS module: dealing with capillary fouling and extraction of pure component patterns from poorly resolved SEC‐SAXS data. Issue 5 (9th September 2016)

• Record Type: Journal Article
• Authors: Brookes, Emre; Vachette, Patrice; Rocco, Mattia; Pérez, Javier
• Is Part Of: Journal of applied crystallography. Volume 49:Issue 5(2016)
• Page Start: 1827
• Page End: 1841
• Publication Date: 2016-09-09
• Subjects: poorly resolved chromatographic peaks -- asymmetric modified Gaussian decomposition -- multi‐resolution modeling -- aldolase supramolecular complexes -- P‐value analysis -- CorMap analysis -- US‐SOMO HPLC‐SAXS module; Crystallography -- Periodicals; 548.05
• DOI: 10.1107/S1600576716011201
• Languages: English
• ISSNs: 0021-8898

Abstract

Abstract : 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. Abstract : 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.