Determination of phthalates in liquor beverages by single quadrupole GC-MS

Significance of the Topic

Phthalate acid esters (PAEs) are widely used as plasticizers in polymer materials and can migrate into beverages, especially those with high ethanol content. These compounds act as endocrine disruptors and have been linked to carcinogenic, teratogenic and mutagenic effects. Regulatory agencies worldwide prohibit phthalates in food contact materials, making sensitive and accurate detection in alcoholic beverages essential for consumer safety and quality control.

Goals and Overview of the Study

This study aimed to develop and validate a rapid, sensitive and accurate gas chromatography–mass spectrometry (GC-MS) method using a single quadrupole system for trace determination of 15 phthalate esters in high-alcohol content beverages. The work covered optimization of sample preparation, instrument conditions, method validation and application to commercial liquor samples.

Methodology and Instrumentation

Sample preparation involved heating 5 mL of liquor to remove ethanol, followed by extraction with 2 mL n-hexane. After phase separation, the organic layer was analyzed by GC-MS.

• Gas chromatograph: Thermo Scientific TRACE 1310 GC with Instant Connect Split/Splitless injector and TRACEGOLD TG-35MS column (30 m × 0.25 mm × 0.25 µm).
• Carrier gas: Helium, constant flow at 1 mL/min.
• Oven program: 80 °C initial hold for 1 min, ramp at 10 °C/min to 280 °C, hold 10 min.
• MS system: Thermo Scientific ISQ single quadrupole GC-MS; EI ionization at 70 eV; full-scan 50–350 Da; acquisition rate 0.2 s; source and transfer line at 280 °C.

Main Results and Discussion

Optimization of ethanol removal prior to extraction improved recoveries from as low as 35%–60% to a consistent 89%–112% across all target PAEs. Chromatographic separation and mass spectral matching against the NIST library confirmed compound identities with excellent selectivity. Calibration curves over 0.10–4.00 mg/L (0.40–4.00 mg/L for unresolved dinonyl phthalate) exhibited correlation coefficients above 0.998. Limits of detection ranged from 0.1 to 0.5 µg/L and limits of quantification from 0.3 to 1.5 µg/L. Method precision at spiked levels of 0.10 and 0.30 mg/L showed recoveries of 83%–110% and relative standard deviations between 1.3% and 8.4%. Analysis of eight commercial liquor samples revealed frequent occurrence of diisobutyl phthalate, dibutyl phthalate and di(2-ethylhexyl) phthalate, with DEHP detected in all samples.

Benefits and Practical Applications

This validated GC-MS method provides a robust tool for regulatory compliance, quality assurance and routine monitoring of phthalate contaminants in alcoholic beverages. The rapid sample preparation and full-scan MS detection enable broad screening of multiple esters with high sensitivity and specificity.

Future Trends and Potential Applications

Advances may include integration of high-resolution mass spectrometry for enhanced selectivity, automated sample preparation workflows for increased throughput, on-site portable GC-MS analysis and extension of the methodology to other food and environmental matrices.

Conclusion

A simple ethanol removal and n-hexane extraction procedure combined with single quadrupole GC-MS yields reliable trace-level phthalate analysis in high-alcohol beverages. The method demonstrates excellent linearity, sensitivity, precision and accuracy, making it suitable for routine laboratory use.

Reference

1. Kavlock RJ, Daston GP, DeRosa C, Fenner-Crisp P, Gray LE, Kaattari S, et al. Research needs for the risk assessment of health and environmental effects of endocrine disruptors: a report of the U.S. EPA-sponsored workshop. Environ Health Perspect. 1996;104(Suppl 4):715–40.
2. Shao D. Determination of phthalate ester residues in white spirit by GC-MS. Chem Anal Metrol. 2010;19(6):33–35.