Automated on-line liquid-liquid extraction in a multisyringe flow injection analysis manifold for migration studies in food-contact materials: analysis of 4,4´-dihydroxybiphenyl

ABSTRACT

Packaging may represent a source of food contamination, as different organic compounds and degradation compounds may migrate from packaging to foodstuff. For fatty foods, rectified olive oil is the common simulant, which implies time-consuming and laborious liquid-liquid extraction (LLE) procedures to isolate the contaminant(s) from the oil. Here we propose a Multisyringe Flow Injection Analysis manifold to automate this sample treatment, using the monomer 4,4´-dihydroxybiphenyl as the contaminant. The LLE procedure, using water as extractant, was fully automated. After the on-line LLE, the resulting extract was pumped through a fluorescence detector, inside which a flow-cell filled with C₁₈ silica gel solid support was placed. The analyte was pre-concentrated on the solid support (in which the analytical signal was directly recorded), so improving the sensitivity of the system. Under optimum conditions, the method detection limit is 0.05 mg kg⁻¹, well within the specific migration limit of 6 mg kg⁻¹. The method developed was compared with the standard CEN test method (off-line LLE and HPLC determination) observing savings in sample and reagents of 90% and a 7-fold increase in sample throughput.

Graphical abstract

KEYWORDS:

• Olive oil
• food contact
• migration
• polymer
• multisyringe flow injection analysis
• liquid-liquid extraction

Supplementary material

Supplemental data for this article can be accessed on the publisher’s website.

Disclosure statement

The authors declare that they have no conflict of interest.

Additional information

Funding

Technical and human support provided by CICT of Universidad de Jaén (UJA, MINECO, Junta de Andalucía, FEDER) is gratefully acknowledged. This study was funded by “Ministerio de Economía y Competitividad” (grant number CTQ2016-7511-R);Ministerio de Economía y Competitividad [CTQ2016-7511-R].