Rapid determination of methanol content in paper materials by alkaline extraction, coupled with headspace analysis

• Measure methanol content in paper materials by alkaline extraction and HS-GC.
• Calculate methanol content by an equation based on three-phase equilibria.
• The method is simple, rapid and suitable for testing methanol in paper products.

This study reports on a rapid method for the determination of methanol in paper-based materials by alkaline extraction, coupled with headspace analysis. Methanol partition equilibria between solid–liquid phases and vapor–liquid phases were conducted in two separate containers, from which an equation for calculating the total methanol content in the original paper sample was derived. It was found that the extraction equilibrium of methanol from solid sample could be achieved within 5 min at room temperature using a high-speed disintegrator, and a subsequent neutralization step is an effective way to prevent methanol from being regenerated at high temperature during headspace equilibration. The results showed that the relative standard deviations for reproducibility tests were in the range of 1.86–6.03%, and the recoveries were in the range of 92.3–107%. The present method is simple and practical; it can be an efficient tool for quantifying the methanol content in paper-based materials and thus play an important role in the investigation of methanol migration behavior in food and beverage packaging.