Optimization of headspace extraction conditions for volatile hydrocarbons from aqueous matrices using experimental design approaches

Abstract

This study presents a robust, statistically validated analytical method for the quantification of C5–C10 volatile petroleum hydrocarbons (VPHs) in aqueous matrices using headspace gas chromatography with flame ionization detection (HS-GC-FID). A central composite face-centered (CCF) experimental design was employed to optimize critical extraction parameters, including sample volume, temperature, and equilibration time. The response variable, defined as the chromatographic peak area per microgram of analyte (Area per μg), was used to model the extraction efficiency. Analysis of variance (ANOVA) confirmed the global significance of the fitted model (R² = 88.86%, RMSE = 4.997, p < 0.0001), with significant main, quadratic, and interaction effects. Sample volume showed the strongest negative impact, while temperature and interaction terms demonstrated synergistic behavior. The optimized conditions improved both sensitivity and reproducibility. The proposed method aligns with ISO 9377-2 principles and provides a reliable, environmentally relevant protocol for trace-level VPH monitoring in water samples.