Technical Support Note-000Determination of Phthalates in Liquor Beverages by Single Quadrupole GC-MS

Importance of the topic

Phthalate acid esters are common plasticizers that can leach from polymer containers into alcoholic beverages. These compounds have been linked to endocrine disruption, reproductive toxicity and carcinogenicity. Sensitive, accurate analysis of trace phthalate residues in liquor is essential to ensure consumer safety and meet international regulatory standards.

Study objectives and overview

This work aimed to adapt and optimize the Chinese standard GB/T 21911-2008 for determining fourteen phthalate esters in spirits. The study focused on efficient sample preparation, robust quantitation by single quadrupole GC-MS and validation of method performance in real commercial liquor samples.

Methodology

Sample preparation involved accurately pipetting 5 mL of spirit into a glass tube, evaporating most of the ethanol in a boiling water bath to a residual volume of 2–3 mL, then cooling and extracting with 2 mL of n-hexane. After phase separation, the hexane extract was transferred to autosampler vials. Matrix-matched calibration standards were prepared by spiking blank liquor samples at 0.1–4.0 mg/L.

Used Instrumentation

• Single quadrupole GC-MS system with splitless injector and liquid autosampler
• Capillary column: TraceGOLD TG-35MS, 30 m × 0.25 mm × 0.25 μm
• Carrier gas helium at 1 mL/min, oven program from 80 °C (1 min) to 280 °C at 10 °C/min (hold 10 min)
• Mass spectrometer operated in EI mode at 70 eV, full scan 50–350 Da, source and transfer line temperatures at 280 °C

Main results and discussion

Removal of ethanol prior to n-hexane extraction greatly improved recoveries for all analytes, rising from as low as 3–14% without removal to 89–112% with. Calibration curves for fifteen phthalates were linear over 0.10–4.00 mg/L (R2 ≥ 0.9969). Limits of detection ranged from 0.1 to 0.5 μg/L (S/N ≥ 3), and limits of quantitation from 0.3 to 1.5 μg/L (S/N ≥ 10). Precision at spike levels of 0.1 and 0.3 mg/L showed recoveries of 83–110% with RSDs below 8.4%. Application to eight commercial spirits revealed frequent contamination by diisobutyl phthalate, dibutyl phthalate and di(2-ethylhexyl) phthalate, with DEHP detected in all samples at up to 0.236 mg/L.

Benefits and practical applications

The optimized method is rapid, requires minimal glassware, and provides reliable quantitation of trace phthalates in high-ethanol matrices. Its sensitivity and wide dynamic range make it suitable for routine quality control in beverage production, regulatory compliance monitoring and contamination source identification.

Future trends and opportunities

Advances may include coupling high-resolution mass spectrometry for improved selectivity, online sample preparation automation to increase throughput, expansion to emerging plasticizers and broader food matrices, and real-time monitoring in production lines to prevent contamination.

Conclusion

An efficient GC-MS method based on single quadrupole instrumentation and ethanol removal has been developed for trace determination of phthalate esters in spirits. The procedure meets regulatory requirements, exhibits excellent recovery, precision and sensitivity, and is readily applicable to commercial sample screening.

References

• China method GB/T 21911-2008 Determination of phthalates in food
• Shao D., Determination of Phthalate Ester Residues in White Spirit by GC-MS, Chemical Analysis and Meterage 19(6) (2010) 33–35