Simultaneous Analysis of Eight Bisphenols in Food Storage Containers Using Liquid Chromatography-Triple Quadrupole Mass Spectrometry

Significance of the topic

Regulatory pressure and toxicological evidence have focused attention on bisphenols migrating from food-contact materials into the diet. Bisphenol A (BPA) is a widely studied endocrine disruptor historically used in polycarbonate and epoxy resins; lowered tolerable daily intakes and expanding restrictions have also increased scrutiny of BPA analogues. Sensitive, selective and rapid analytical methods are therefore essential for routine surveillance of multiple bisphenol species in food-contact polymers such as polypropylene (PP).

Objectives and study overview

The study presents a targeted LC–MS/MS workflow for simultaneous quantification of eight bisphenols (BPA, BPB, BPF, BPS, BPAF, 4,4'-(1,3-dimethylbutylidene)diphenol, phenolphthalein and TBBPA) migrated from commercial PP food storage containers. Two sample-preparation strategies (manual dilution and autosampler-based automated dilution) were developed and evaluated for analytical performance, including recoveries, repeatability and calibration linearity. The method aims to deliver short run times, high selectivity and suitability for routine monitoring in QA/QC laboratories.

Methodology

Sample preparation followed Japan Food Analysis Center guidance for synthetic resin utensils. PP containers were cut, milled and 1.0 g aliquots were subjected to a migration extraction: spikes of reference standards were added and samples were incubated with either ultrapure water (manual dilution) or 30% acetonitrile (ACN) (automated dilution) at 60°C for 30 minutes, then vortexed and centrifuged. The supernatant was spiked with an internal standard (BPA-D16) prior to LC–MS/MS analysis. Two workflows were compared:

• Manual dilution: 10 mL ultrapure water as extraction solvent; internal standard added after centrifugation.
• Automated dilution: autosampler programmed to perform dilution with 30% ACN, add internal standard and inject, reducing manual handling and solvent use.

Calibration used absolute (external) calibration curves prepared in water/ACN matrices; ranges were 0.05–20 ng/mL for BPA and BPS, and 0.1–20 ng/mL for the other analytes (TBBPA quantified over 0.1–20 ng/mL). Method linearity was excellent (R2 > 0.989 for all analytes). Spike–recovery and reproducibility tests followed EU bisphenol guidance (n = 3).

Used instrumentation

The analyses were performed on Shimadzu instrumentation (Nexera X3 autosampler/front-end and LCMS-8060RX triple-quadrupole MS) in negative electrospray ionization (ESI) mode using MRM acquisition. Key parameters and consumables included:

• Analytical column: Shim-pack XR-ODS III (short, high-efficiency column used to obtain sub-6-min separations).
• Delay column: Shim-pack Scepter C18-120 for system protection.
• Injection volume: 10 µL; column temperature: 40°C; flow rate: 0.3 mL/min.
• Mobile phases: ultrapure water (A) and acetonitrile (B); rapid gradient (30% → 40% B in first 2 min, full ACN steps later) to elute all targets within 6 min.
• MS: LCMS-8060RX, MRM mode, interface voltage −3 kV, interface temp ~300°C, heating block 350°C, drying gas 6 L/min, nebulizer 3 L/min.
• Rinse solutions: ACN/2-propanol (50:50 v/v) for needle exterior; R1 rinse adapted when autosampler automated-dilution uses 30% ACN as diluent.
• Internal standard: deuterated BPA (BPA-D16).

Key results and discussion

Separation and run-time:

• All eight bisphenols eluted within a 6-minute window, enabling high throughput.

Linearity and calibration:

• Calibration curves showed excellent linearity across the stated ranges (R2 > 0.989). BPA and BPS were linear down to 0.05 ng/mL; other analytes including TBBPA were linear from 0.1 ng/mL.

Recovery and repeatability:

• Automated-dilution workflow (30% ACN) produced recovery rates of 88.0–100.5% and repeatabilities (RSD, n=3) ≤5.7% for the analytes assessed (Table summary reported in the paper).
• Manual dilution into ultrapure water gave variable recoveries (80.8–94.6%) for most analytes; BPA recovery increased from 80.8% to 92.6% when corrected using the internal standard.
• TBBPA showed poor recovery (<60%) with ultrapure water extraction but substantially improved when 30% ACN was used as the extraction/dilution solvent; nonetheless, TBBPA still required a higher spiking level (10 µg/kg) for quantification compared with other bisphenols (1.0 µg/kg).

Matrix effects and internal standard use:

• BPA quantification benefited from internal standard correction (BPA-D16), improving accuracy. The study highlights the need for isotope-labeled standards to compensate for matrix suppression/enhancement in migration extracts.

Limitations:

• TBBPA recovery remained challenging in water extraction and required organic-rich diluent; alternative pretreatment or cleanup may be necessary for robust TBBPA quantification in certain sample matrices.

Benefits and practical applications

The method delivers rapid, selective and sensitive multianalyte monitoring suitable for routine surveillance of bisphenol migration from PP food-contact materials. Specific practical advantages include:

• Short analysis time (≤6 min) increases laboratory throughput.
• Good linearity and low ng/mL-level calibration ranges allow sensitive quantification relevant to regulatory scrutiny.
• Automated-dilution via the autosampler standardizes pretreatment, reduces labor and solvent consumption, and simplifies calibration by automated addition of ISTD.
• The combination of MRM-based LC–MS/MS and isotope-labeled internal standardization yields robust quantification for most bisphenols in PP extracts.

Future trends and potential applications

Recommended developments and avenues for broader application include:

• Expanded analyte panels to include emerging bisphenol analogues and conjugated metabolites to better represent total dietary exposure.
• Routine use of isotope-labeled standards for each target analyte to further reduce matrix bias and improve accuracy.
• Integration of sample cleanup steps (e.g., SPE, dispersive SPE) or alternative extraction solvents to improve recoveries for halogenated bisphenols like TBBPA.
• Application of high-resolution MS or orthogonal techniques to screen unknown bisphenol derivatives and transformation products.
• Standardization and validation according to regulatory method performance criteria (LOQ/LOD determination, inter-lab validation) to support official control programs.
• Automation and miniaturization to increase throughput and reduce solvent/sample consumption in routine QA/QC labs.

Conclusion

The presented LC–MS/MS workflow (manual and autosampler automated-dilution formats) enables rapid, selective analysis of eight bisphenols migrated from PP food storage containers, with good linearity and acceptable recoveries and repeatabilities for seven compounds at 1.0 µg/kg spiking levels. Use of 30% ACN in the automated workflow improved recoveries for TBBPA and overall method robustness. Internal standard correction (BPA-D16) improved BPA accuracy. Remaining challenges include optimizing pretreatment for certain halogenated bisphenols and extending validation for routine regulatory application.

References

1. European Commission. Regulation (EU) 2024/3190.
2. European Commission. Official Journal C_2025/0721.