Accurate determination of residual acrylic acid in superabsorbent polymer of hygiene products by headspace gas chromatography

•Accurate and rapid determination of residual acrylic acid in superabsorbent polymer.•The method can determine the amount of adsorbed acrylic acid by polymer matrix in the process of sample extraction.•The present method can apply for determining total residual acrylic acid in a wide variety of applications from processing of superabsorbent polymer to commercial products quality control.

This work reports on a method for the determination of residual acrylic acid (AA) in the superabsorbent polymers for hygiene products by headspace analysis. It was based on water extraction for the polymer sample at a room temperature for 50 min. Then, the AA in the extractant reacted with bicarbonate solution in a closed headspace sample vial, from which the carbon dioxide generated from the reaction (within 20 min at 70 °C) was detected by gas chromatography (GC). It was found that there is adsorption partition equilibrium of AA between solid-liquid phases. Therefore, an equation for calculating the total AA content in the original polymers sample was derived based on the above phase equilibrium. The results show that the HS-GC method has good precision (RSD < 2.51%) and good accuracy (recoveries from 93 to 105%); the limit of quantification (LOQ) was 373 mg/kg. The present method is rapid, accurate, and suitable for determining total residual acrylic acid in a wide variety of applications from processing of superabsorbent polymer to commercial products quality control.