Methylparaben sodium can be analyzed by this reverse phase (RP) HPLC method with simple conditions. The mobile phase contains an acetonitrile (MeCN), water, and phosphoric acid. For Mass-Spec (MS) compatible applications the phosphoric acid needs to be replaced with formic acid. Smaller 3 µm particles columns available for fast UPLC applications. This liquid chromatography method is scalable and can be used for isolation impurities in preparative separation. It also suitable for pharmacokinetics.
Carbocysteine is a medication that reduces the viscosity of mucus making it easier to cough up. Methylparaben and propylparaben are used as preservatives in cosmetics, pharmaceuticals and food. They can be separated in HPLC on a Primesep 100 mixed-mode column by both hydrophobic and ionic properties present on the stationary phase. The analytical method uses acetonitrile (ACN) gradient and water with sulfuric acid (H2SO4) as buffer and UV detected at 200nm.