Polymer Liquid Adsorption Chromatography
Copolymer analysis is challenging because at least two distributions can be present simultaneously: the molar mass distribution (MMD) and the chemical composition distribution (CCD).
While there are molar mass sensitive detectors for the determination of the MMD of homopolymers, the applicability of these detectors for copolymers suffers from potential co-elution in GPC/SEC and (in case of lightscattering) from the dependence of the dn/dc on composition. In addition, these detectors do not provide any insight into the CCD.
The CCD can be determined using several techniques including dual detection, which was discussed in the first chapter of this eBook. In this case, GPC/SEC separation based on the size (hydrodynamic volume) is applied and the CCD of, for example, block copolymers is determined using at least two different detectors.
Best of the Week: Food Analysis, Chemical Migration in Plastic Bottles, STEM Researcher of the Year
December 20th 2024Top articles published this week include the launch of our “From Lab to Table” content series, a Q&A interview about using liquid chromatography–high-resolution mass spectrometry (LC–HRMS) to assess chemical hazards in plastic bottles, and a piece recognizing Brett Paull for being named Tasmanian STEM Researcher of the Year.
Using LC-MS/MS to Measure Testosterone in Dried Blood Spots
December 19th 2024Testosterone measurements are typically performed using serum or plasma, but this presents several logistical challenges, especially for sample collection, storage, and transport. In a recently published article, Yehudah Gruenstein of the University of Miami explored key insights gained from dried blood spot assay validation for testosterone measurement.
Determination of Pharmaceuticals by Capillary HPLC-MS/MS (Dec 2024)
December 19th 2024This application note demonstrates the use of a compact portable capillary liquid chromatograph, the Axcend Focus LC, coupled to an Agilent Ultivo triple quadrupole mass spectrometer for quantitative analysis of pharmaceutical drugs in model aqueous samples.
