Matrix-Compatible APGC-MS/MS for Trace Determination of Legacy and Novel Brominated Flame Retardants in Complex Food Matrices

The increasing restrictions on various traditional brominated flame retardants (BFRs) have led to the growing use of alternative and new brominated flame retardants (NBFRs) in commercial applications, raising new concerns about their presence in the food chain. However, due to severe matrix interference, low residue concentrations, and the unfavorable chromatographic and ionization behavior of highly brominated compounds, their trace determination in lipid- and protein-rich foods remains an analytical challenge. In this study, we developed and validated a soft ionization atmospheric pressure gas chromatography–tandem mass spectrometry (APGC-MS/MS) method for the simultaneous determination of 15 conventional and new brominated flame retardants, including TBECH, TBCO, PBEB, PBT, HBB, DPTE, EHTBB, TBBPA, TBPH, HCDBCO, α-HBCD, BTBPE, TBBPA-DBPE, BDE-209, and DBDPE. To enhance quantitative stability, particularly for highly brominated analytes, the analytical workflow combined a 15 m DB-5HT column with optimized APGC ionization conditions. By integrating accelerated solvent extraction, enhanced matrix removal-lipid (EMR-lipid) treatment, multi-layer silica/alumina purification, and acidified silica purification steps, a matrix-specific extraction and purification workflow suitable for poultry meat, infant formula, and seafood was established. Quantification was performed using a matrix-matched calibration method combined with isotopically labeled internal standard correction. The method detection limits (MDLs) were 0.31–73 pg/g w/w in infant formula, 0.69–189 pg/g w/w in poultry products, and 1.4–172 pg/g w/w in seafood, with corresponding method limits of quantification (MLOQs) of 0.99–264, 2.4–680, and 5.1–634 pg/g w/w, respectively. Recovery rates ranged from 80.2% to 112.8%, with both intra-day and inter-day relative standard deviations (RSDs) below 16.8%, and matrix effects controlled between 75.2% and 103.5%. This validated method was applied to 140 poultry meat samples collected in Jiangsu Province, China. PBT, HBB, and DPTE were identified as the major quantifiable NBFRs, while BTBPE was detected less frequently, and highly brominated compounds were generally below MLOQs. All 22 infant formula and foods for special medical purposes samples had target analytes below the MLOQs under the present analytical conditions. Screening-level dietary exposure estimates based on poultry consumption indicated low adult intakes, with mean estimated daily intakes (EDIs) of 20.5, 10.8, 8.8, and 6.2 pg/kg bw/day for PBT, BTBPE, HBB, and DPTE, respectively. Overall, this APGC-MS/MS workflow provides a sensitive, matrix-compatible confirmatory approach for multi-class BFR monitoring in complex foods and supports screening-level exposure assessment for emerging alternative flame retardants.