Wyatt μDAWN MALS detector and Optilab UT-rEX RI detector

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Wyatt Technology has announced an application note which outlines the combined use of the Wyatt μDAWN multiangle light scattering (MALS) detector and the Optilab UT-rEX refractive index (RI) detector to measure the absolute molecular weight (or molar mass) and size of eluting species in ultrahigh-performance liquid chromatography (UHPLC). The instruments, engineered for use with ultrahigh-performance size exclusion chromatography (UHP-SEC), are said to overcome the limitations associated with conventional UHP-SEC for the characterisation of size and composition of aggregates or fragments in a biomolecular sample.

Conventional SEC relies on reference standards to calibrate column elution time as a function of molar mass. However, these standards often do not accurately represent the conformation of the sample, or the sample may exhibit column interactions that change its elution properties relative to the standard. The application note discusses how UHP-SEC-MALS provides improved resolution, higher throughput, less solvent and smaller sample consumption for analysis of precious biological samples in comparison to standard SEC-MALS.

Light scattering detectors designed for standard HPLC have generally been incompatible with UHPLC, but the combination of the μDAWN and UT-rEX results in fast and efficient characterisation of biomolecular samples. The detectors are said to maintain the narrow peak widths typical of UHPLC while providing even more information than standard SEC-MALS due to the upstream resolution obtained with 300 mm UHPLC columns. The time difference between the two techniques demonstrates how UHP-SEC-MALS results in faster analyses.

With the introduction of the μDAWN, users have access to all the in-depth analyses available with the miniDAWN TREOS for UHPLC. The range of instrumentation, providing triple detection with UV, MALS and RI, also enables the application of protein conjugate analysis to identify the amount of post-translational modification, associated detergent, drug-conjugate or other additions to a polypeptide background.