F molar mass4/18/2023 ![]() Protein analysis - including an Optilab is very useful since nearly all proteins have the same dRI response ( dn/dc) - it is not necessary to know the extinction coefficient of each peak.Most SEC-MALS users find it beneficial to include an Optilab ® dRI detector, or microOptilab ™ for UHPLC. Native HPLC software or a hand-held controller is used to control the HPLC system. Sample injection and ASTRA data collection are synchronized via analog auto-inject signal, and concentration data are acquired via analog output from the concentration detector.MALS is plumbed downstream of the UV detector or upstream of the dRI detector.miniDAWN and microDAWN have 3 angular detectors they cover a molar mass range of 200 to 10 7 g/mol (10 6 g/mol for linear polymers), and a size range of 10 to 50 nm.DAWN has 18 angular detectors it covers a molar mass range of 200 to 10 9 g/mol and a size range of 10 to 500 nm with maximum sensitivity.HP/FPLC-SEC-MALS uses a DAWN ® or miniDAWN ® MALS instrument UHP-SEC-MALS requires a microDAWN ®.Learn more about these and other types of MALS measurements on the Other Techniques Application Notes page.įor basic SEC-MALS, all you need are a standard HPLC or FPLC system including a concentration detector (UV for proteins, dRI for polymers), SEC column(s), a MALS instrument and a computer with ASTRA ® software for data acquisition and analysis. ![]() Online MALS analysis give instant identification of peaks, with no need to collect and analyze offline. MALS can also be combined with ion-exchange chromatography (IEX-MALS) and reverse-phase chromatography (RPC-MALS), which-unlike SEC-cannot be calibrated to assign a molar mass to any specific retention time. When that does not work, either due to analyte-column interactions or simply analytes beyond the useful size range of SEC, MALS can be coupled to a different separation technique, field-flow fractionation. SEC-MALS is only effective if good separation is achieved on the SEC column. ![]() For more details on the theory of MALS, please see our MALS Theory page. In addition, the analyte’s dn/dc value (specific refractive index increment) in the mobile phase must be known or measured (this is easier than it sounds!). Most of the constants used to determine M and R g are related to system optical properties such as laser wavelength and solvent (mobile phase) refractive index.
0 Comments
Leave a Reply.AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |