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.