A Simple, Fast, and Reliable LC-MS/MS Method for Determination and Quantification of Phthalates in Distilled Beverages

Importance of the Topic

Phthalates are common plasticizers known to leach into food and beverages, posing potential endocrine-disrupting and reproductive hazards. Regulatory bodies worldwide set migration limits for these compounds, making rapid and reliable screening methods essential to ensure consumer safety and regulatory compliance in distilled spirits.

Objectives and Study Overview

This study aimed to develop a single, fast, and robust LC-MS/MS protocol for separation, detection, and quantification of seven priority phthalates (DMP, DEP, DBP, BBP, DEHP, DNOP, DINP) in a range of distilled beverages. Method applicability was demonstrated across brandy, gin, whisky, tequila, and other spirit samples.

Methodology and Instrumentation Used

A “dilute and shoot” approach was combined with UltraPerformance Liquid Chromatography–tandem mass spectrometry. Key parameters included:

• Chromatography: Waters ACQUITY UPLC H-Class, BEH C18 column (2.1×50 mm, 1.7 µm), 40 °C, 0.5 mL/min; mobile phases A: water + 0.1% formic acid, B: methanol + 0.1% formic acid; total run time 11 min.
• Background Control: ACQUITY UPLC Isolator Column positioned upstream to retain ubiquitous phthalate contaminants and improve sample-analyte resolution.
• Mass Spectrometry: Waters Xevo TQD in positive ESI mode, multiple reaction monitoring (two MRM transitions per analyte) for quantification and confirmation.
• Data Processing: MassLynx and TargetLynx software for acquisition, calibration, and trend analysis.

Main Results and Discussion

All seven phthalates were baseline-separated within 11 minutes, including isomeric DEHP and DNOP. Matrix-matched calibration in whisky showed linear responses (r²>0.99) from 5 to 100 µg/L. Limits of detection and quantification were ≤1 µg/L for six phthalates and 5/10 µg/L for DINP. A 100-injection robustness study in spiked whisky yielded retention time RSD<0.1% and area RSD<6% for all compounds. Application to six commercial spirits detected only trace DEHP (<5 µg/L) in one brandy sample, confirming method specificity and minimal background interference.

Benefits and Practical Applications

• High throughput: simple sample prep and 11-minute analysis.
• Reliable quantification at low µg/L levels suitable for regulatory limits.
• Reduced background thanks to isolator column integration.
• Versatile single-method workflow for multiple spirit matrices.

Future Trends and Applications

Extension to non-distilled beverages, incorporation of online sample cleanup, and coupling with high-resolution MS could broaden analyte scope. Emerging green solvents and miniaturized UPLC setups may further streamline phthalate screening in food-contact materials.

Conclusion

A robust, rapid, and sensitive UPLC-MS/MS method was established for routine monitoring of key phthalates in distilled spirits. Its simplicity and high throughput support quality control and regulatory compliance across the beverage industry.

References

• H.Y. Shen. Simultaneous screening and determination of eight phthalates in plastic products for food use by sonication-assisted extraction/GC-MS. J. Chromatogr. A. 2005;1098:734–739.