Simultaneous Determination of Four Per- and Polyfluoroalkyl Substances (PFAS) in DHA Products using LC-MS/MS for...

Docosahexaenoic acid (DHA) is a critical dietary supplement for vulnerable populations (e.g., infants, pregnant women), but contamination by per- and polyfluoroalkyl substances (PFAS)-persistent "forever chemicals"-poses potential health risks. Currently, no standardized methods exist for PFAS detection in DHA products, hindering quality control and risk assessment.

To develop and validate a sensitive LC-MS/MS method for simultaneous determination of four PFAS (PFOA, PFODA, PFOS, and PFBS) in DHA matrices (algal oil and fish oil) and support product safety evaluation.

Samples were extracted with 50% methanol/acetonitrile (v/v) via ultrasonication (40 °C, 20 min), followed by centrifugation and filtration. Chromatographic separation was achieved on a Phenomenex Kinetex F5 column (100 × 3.0 mm, 2.6 μm) with gradient elution (mobile phase: 2 mmol/L ammonium formate aqueous solution-methanol) in 12 min. Detection was performed via negative electrospray ionization (ESI-) in multiple reaction monitoring (MRM) mode. Method validation included linearity, limits of detection (LODs)/quantitation (LOQs), accuracy, precision, matrix effects, and stability. Thirteen commercial DHA products (11 algal oil, 2 fish oil) were analyzed.

Linearity (r ≥ 0.99) were achieved for PFAS; LODs/LOQs: 0.02/0.04 ng/mL. Recoveries at three spiking levels (0.1, 0.5, 1.0, 1.5 ng/mL) were ranged from 92.1%-108.4%, with RSDs of 2.8%-5.6%. Matrix effects were effectively corrected via matrix-matched calibration. Trace PFAS were detected in 3/13 samples, all below regulatory limits.

The developed method is reliable for routine PFAS detection in DHA matrixes, providing practical technical support for quality control and risk assessment for DHA supplements for vulnerable populations.

Rapid (12 min), sensitive, and applicable to both algal oil and fish oil matrixes.