Determination of residual monomers in polycarboxylate superplasticizer using high performance liquid chromatography

A procedure was developed for the determination of residual monomers in polycarboxylate superplasticizer (PCs) by reversed-phase high performance liquid chromatography (RP-HPLC). Four kinds of residual monomers were well separated and determined on a SinoChrom ODS-BP (C18) column with mobile phases composed of acetonitrile and phosphate buffer solution. The monomers were detected by UV detector at 205 nm and quantitatively analyzed with an external standard method. For those residual monomers, the linear response ranged from 4.0×10−6 mol·L−1 to 2.0×10−3 mol·L−1. The determination limit of acrylic acid, sodium methylallyl sulfonate and 2-Acrylamido-2-methylpropane sulfonic acid was 0.02×10−5 mol·L−1, while that of methoxy-polyethylene glycol monoacrylate was 0.1×10−5 mol·L−1. The relative standard deviation (RSD) of high concentration samples was less than 1%, while that of the low concentration samples was between 1%–4%. The standard (additional) recovery ratio was 97.4%–104.2%.