Determination of residual monomers in latex by headspace hollow fiber protected liquid-phase microextraction combined with high-performance liquid chromatography

A simple and efficient method based on hollow fiber protected headspace liquid-phase in conjunction with high performance liquid chromatography has been introduced for extraction and determination of three residual monomers (2-ethylhexyl acrylate (EHA), vinyl acetate (VA), glycidyl methacrylate (GM)) in polymer latex. Using this methodology, the analytes of interest extracted from a sample are led into organic solvent located inside the porous hollow fiber membrane. Initially, several experimental parameters were controlled and optimized and the optimum conditions were reached with 8 cm neatly cut hollow fibers containing heptanol, which were exposed to the headspace of a 12 mL sample solution containing 20% (w/v) NaCl thermostated at 110 °C and stirred at 800 rpm for 20 min. Finally, 20 μL of the extraction solution was withdrawn into a syringe and injected into HPLC for analysis. The calibration curves were linear (r² ≥ 0.994) over the concentration range of 0.05-10 mg L⁻¹ for VA and 0.02-10 mg L⁻¹ for other analytes. The relative standard deviation (RSD%) for three-replicate extractions and measurements was below 8.6%. The limits of detection of this method for quantitative determination of the analytes were found within the range of 0.005 to 0.011 mg kg⁻¹ with the enrichment factors within the 5-164 range. The method was successfully applied for determination of residual monomers in polymer latex.