Analysis of bisphenol A leaching from baby feeding bottles

Significance of the Topic

Bisphenol A is widely used in polycarbonate plastics and epoxy resins. It can leach into food and beverages under common conditions, posing endocrine disruption risks. Accurate quantification of BPA and its analog BPF in consumer products, especially baby bottles, is critical for ensuring safety and regulatory compliance.

Objectives and Study Overview

This application note presents a method for simultaneous determination of BPA and BPF leached from polycarbonate baby bottles. Key aims:

• Develop and partially validate an HPLC method with fluorescence detection for BPA and BPF quantification.
• Automate calibration and sample preparation using an Agilent 7696A Sample Prep WorkBench.
• Demonstrate method transfer to UHPLC and evaluate performance improvements.

Methodology and Instrumentation

Sample extraction relied on solid phase extraction (SPE) of leachates from 250 mL boiling water rinses of baby bottles, followed by nitrogen evaporation and reconstitution. Automated dilution series were prepared on an Agilent 7696A Sample Prep WorkBench. Chromatographic separation and detection used:

• Agilent 1260 Infinity LC with ZORBAX Eclipse Plus C18 (4.6×100 mm, 5 µm), fluorescence detection (Ex 230 nm/Em 316 nm).
• Agilent 1290 Infinity UHPLC with ZORBAX Eclipse Plus C18 (4.6×100 mm, 1.8 µm), same detector settings.
• Mobile phase: 10 mM potassium phosphate (A) and acetonitrile (B) with step gradient.

Main Results and Discussion

The method achieved limits of detection of 0.19 ng/mL (S/N>3) and quantitation of 1.06 ng/mL (S/N>10) for BPA, with similar values for BPF (LOQ 0.46 ng/mL). Calibration was linear (R2>0.9999) over 1.06–171 ng/mL. Precision (≤7.2% RSD for peak area) and retention time stability (<0.14% RSD) met validation criteria. Recovery experiments yielded approximately 80% for BPA. Robustness testing showed the method is sensitive to column temperature, flow rate, excitation wavelength, and buffer concentration, underscoring the need for tight control.

When applied to three baby bottle brands:

• BPA concentrations ranged from 0.5 to 4.5 ng/mL; BPF was not detected.
• Values were below the EPA reference dose (50 µg/kg/day) but warrant monitoring due to potential health concerns.

Transferring to UHPLC improved chromatographic performance: peaks were narrower, better resolved (resolution BPA/BPF increased from 1.9 to 2.5), and S/N ratios almost doubled, enhancing sensitivity.

Benefits and Practical Applications

The combined SPE–(U)HPLC–FLD workflow provides:

• Automated calibration and sample prep to reduce analyst time and variability.
• Sufficient sensitivity and throughput for routine QC of food-contact materials.
• Compatibility with existing HPLC and UHPLC platforms for flexible method deployment.

Future Trends and Applications

Advancements may include:

• Further miniaturization and online SPE integration for higher throughput.
• Coupling with mass spectrometry to broaden analyte scope and structural confirmation.
• Extension to other BPA analogs and degradation products in diverse consumer products.

Conclusion

A robust, partially validated method for quantifying BPA and BPF in baby bottles was established on Agilent LC platforms. Automated sample handling and method transfer to UHPLC yielded improved resolution and sensitivity. This approach supports effective safety monitoring of plastic food-contact materials.

References

1. US EPA, BISPHENOL A (CASRN 80-05-7), 2011.
2. Ballesteros-Gomez et al., J. Chromatogr. A 1216:449–469, 2009.
3. ASTM D7574-09 Standard Test Method for Determination of Bisphenol A in Environmental Waters by LC-MS/MS.
4. Snyder, W.D., Agilent Application Note 5990-6850EN, 2010.
5. Sun et al., J. Chromatogr. B 749:49–56, 2000.
6. Ritter, S.K., Chem. Eng. News 89:14–19, 2011.