Determination of 20 Phthalic Acid Esters in Alcoholic Drinks by Ultra High Performance Liquid Chromatography/Tandem Mass Spectrometry

Significance of the Topic

Phthalic acid esters (PAEs) are widely used plasticizers that can migrate from packaging materials into beverages, posing potential reproductive and developmental health risks. Monitoring their levels in alcoholic drinks is essential to ensure consumer safety and regulatory compliance.

Study Objectives and Overview

This study focused on developing a rapid, sensitive and reliable method for the simultaneous determination of 20 common PAEs in alcoholic beverages. Ultra high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) was selected to achieve fast separation and low detection limits.

Materials and Methods

Sample Preparation

• Five grams of alcoholic drink were accurately weighed and centrifuged at 6 000 rpm for 20 minutes.
• The clear supernatant was directly injected into the UHPLC-MS/MS system.

Chromatographic Conditions

• Column: Shim-pack XR-ODSIII (150 mm × 2.0 mm i.d., 2.2 µm) with a 50 mm Inertsil ODS-4 delay column to minimize background.
• Mobile phases: 5 mmol/L ammonium acetate in water (A) and methanol (B).
• Gradient: 45→90% B (0–6.5 min), 90→100% B (6.5–7.0 min), hold 100% B (7.0–9.9 min), return to 45% B (9.9–10.0 min).
• Flow rate: 0.4 mL/min; column temperature: 45 °C; injection volume: 10 µL.

Tandem Mass Spectrometry

• Instrument: Shimadzu LCMS-8040 triple quadrupole with electrospray ionization in positive mode.
• Source parameters: DL 250 °C, heat block 450 °C, nebulizing gas 3 L/min, drying gas 15 L/min.
• MRM transitions optimized for each PAE with dwell time 15 ms and pause time 3 ms.

Results and Discussion

All 20 PAEs were baseline-separated within 11 minutes. Calibration was linear over 10–200 µg/L (r > 0.999). Limits of detection ranged from 0.02–1.67 µg/L and limits of quantitation from 0.06–5.00 µg/L. Repeatability studies at 20, 50 and 100 µg/L showed retention time RSDs below 0.26% and peak area RSDs under 4.8%. Recoveries in spiked samples (50 and 100 µg/kg) ranged from 78% to 127%. Application to commercial alcoholic beverages revealed DBP and DIBP at levels up to 154.1 µg/kg and 18.7 µg/kg in a distilled liquor sample, demonstrating practical relevance.

Benefits and Practical Applications

This UHPLC-MS/MS method offers:

• Rapid analysis with full separation in under 11 minutes.
• High sensitivity suitable for trace-level monitoring.
• Strong linearity, precision and accuracy for routine quality control.
• Applicability to a wide range of alcoholic matrices, supporting regulatory testing and risk assessment.

Future Trends and Opportunities

Emerging directions include coupling UHPLC with high-resolution mass spectrometry for non-target screening, automating sample handling for higher throughput, expanding to other beverage and food matrices, and adopting greener solvents and miniaturized devices to reduce waste.

Conclusion

A robust UHPLC-MS/MS protocol has been established for the quantitative determination of 20 phthalic acid esters in alcoholic drinks. The method combines speed, sensitivity and reliability, making it well suited for routine monitoring and ensuring consumer safety.