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US‐SOMO HPLC‐SAXS module: dealing with capillary fouling and extraction of pure component patterns from poorly resolved SEC‐SAXS data
Author(s) -
Brookes Emre,
Vachette Patrice,
Rocco Mattia,
Pérez Javier
Publication year - 2016
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s1600576716011201
Subject(s) - small angle x ray scattering , scattering , gaussian , size exclusion chromatography , capillary action , materials science , analytical chemistry (journal) , chromatography , chemistry , optics , physics , composite material , biochemistry , enzyme , computational chemistry
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.