Rapid Solvent-Free Screening of Mineral Oil Hydrocarbons in Pulp and Paper by Headspace Solid-Phase Microextraction coupled with Gas Chromatography–Mass Spectrometry

Mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH) are relevant contaminants in paper and board intended for food contact applications. Analysis is usually done using a liquid extraction followed by the established state-of-art method based on liquid chromatography–gas chromatography with flame ionisation detection (HPLC–GC–FID). This method is however time and resource demanding. In this study, headspace solid-phase microextraction coupled to gas chromatography–mass spectrometry (HS–SPME–GC–MS) was evaluated as a rapid, solvent-free screening approach for mineral oil hydrocarbons (MOH) contaminations in pulp and paper samples and compared to the established HPLC–GC–FID method. Ten pulp samples, originating from different production batches, and three paper samples were analysed by both techniques. The MOH concentrations (C10-C35 range) determined by HS–SPME–GC–MS ranged from <88.9 to 531 ± 80 mg kg⁻¹, while values obtained by HPLC–GC–FID ranged from 12 ± 2 to 359 ± 40 mg kg⁻¹. A good agreement between the two methods was observed. Validation of the screening approach gave a linear working range up to 450 mg kg -1 , limit of detection (LOD) of 27.5 mg kg -1 and limit of quantification (LOQ) of 88.9 mg kg -1 . Although limitations and further optimisation potential in the HS-SPME approach were identified, it provided a reliable semi-quantitative estimation of MOH levels, while also enabling screening for non-intentionally added substances. It therefore represents a suitable complementary screening tool for the assessment of MOH contamination in pulp and paper matrices, with a lower environmental impact as determined by AGREEprep.