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Per-Aqueous Liquid Chromatography for the Separation of Polar Compounds‑Preparation and Characterization of Poly (ethylene oxide‑co‑dimethylsiloxane) Based Stationary Phase


United Chemical Technologies is widely known for our high-quality solid phase extraction products and stationary phases. Though we full equipped to make custom bonded phases for clients, we love to see what researchers discover on their own.

A research group from the Instituto de Ciências Exatas e Naturais do Pontal in Brazil is studying a form of liquid chromatography known as per-Aqueous Liquid Chromatography (PALC). This is a very similar type of chromatography as Hydrophilic Interaction Liquid Chromatography (HILIC) that aims to separate hydrophilic and polar compounds, those which present low retention and/or separation in normal reverse phase methods, by using a hydrophilic stationary phase, and a mobile phase that contains a high acetonitrile content between 70-95%.

The problem with this type of chromatography is that acetonitrile is a “Problematic” solvent when it comes to considering the volatility and toxicity of the acetonitrile waste. PALC, distinguished by its mixed interaction mechanisms, is a greener alternative as it aims to use a mobile phase made up of 70-100% water to separate the same polar/hydrophilic compounds.

The research group in Brazil bonded United Chemical Technologies Dimethylsiloxane-Ethylene Oxide, Copolymer (130 cS; PS073) to 5 µm silica gel using a thermal process. They packed this newly formed phase into HPLC columns and used mixtures of pharmaceuticals and pesticides to evaluate the efficacy of the separation, as compared to a C18 phase, using mobile phases comprised of 0.5 M ammonium acetate and acetonitrile.

For the pharmaceuticals the maximum amount of acetonitrile used was 20%, and 30% for pesticides, thereby decreasing the overall need for a problematic solvent. As the PALC term appears to have been coined in 2009, this type of chromatography is still in the infancy stages, so we expect to see more progress in the very near future.

Citation: Carvalho, G. O.; Santos, A. L. R.; Faria, A. M., Per-Aqueous Liquid Chromatography for the Separation of Polar Compounds‑Preparation and Characterization of Poly (ethylene oxide‑co‑ dimethylsiloxane) Based Stationary Phase, J. Braz. Chem. Soc., 2022, 33(11), 1299-1308.

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