Determination of 17 Organotin Compounds in Beverages Using Triple Quadrupole GC-MS/MS System

Importance of the topic

Organotin compounds (OTCs) are widely used as polymer stabilizers, insecticides, and antifouling agents on ship hulls, leading to environmental contamination and potential human exposure through the food chain.
Due to their endocrine-disrupting properties, sensitive and reliable analytical methods are essential for monitoring trace levels of OTCs in beverages to safeguard public health.

Objectives and Study Overview

This study aimed to develop a rapid, sensitive, and robust GC-MS/MS method for quantifying 17 organotin species in various beverages using small sample volumes.
The method targets a low detection limit of 0.1 µg/kg in beverages, covers a wide concentration range, and simplifies sample preparation for routine analysis.

Methodology and Instrumentation

Sample Preparation:

• Weigh 10 mL of beverage, add methanol and acetate buffer, and derivatize with NaBEt4 for 30 minutes.
• Perform liquid–liquid extraction using 1 mL hexane; vortex and separate phases.
• Collect and filter the organic phase for injection.

Instrumentation:

• GC System: Agilent 7890A with HP-5 MS UI capillary column (30 m × 0.25 mm, 0.25 µm).
• Oven Program: 50 °C (1.5 min), ramp 10 °C/min to 300 °C, hold 1 min.
• MS: Agilent 7000B triple quadrupole in MRM mode with EI source at 70 eV.
• Carrier Gas: Helium at 1.1 mL/min; injection 2 µL splitless.

Key Results and Discussion

Chromatographic separation was achieved in 22 minutes, with baseline resolution of 15 of 17 derivatives; coeluting pairs were resolved by MRM transitions.
Calibration was linear from 0.001 to 0.200 mg/L (effective sample range 0.0001–0.0200 mg/L) with R2 > 0.995 for all compounds.
Recovery studies at spiking levels of 0.001 and 0.005 mg/L yielded average recoveries between 70–120% and RSDs below 10% for most analytes.
Application to 11 beverage samples detected dimethyltin and monobutyltin at 0.27 and 0.39 µg/L in one sample.

Benefits and Practical Applications

The method offers high sensitivity, selectivity, and throughput for both qualitative screening and quantitative trace analysis of multiple organotin species in beverages.
Its simple derivatization and extraction steps are compatible with routine laboratory workflows and QA/QC protocols.

Future Trends and Applications

Further developments may include automation of sample preparation, extension to other food and environmental matrices, and integration with advanced data analysis tools for high-throughput monitoring.
Emerging mass spectrometry platforms and novel derivatization strategies could improve detection limits and broaden analyte coverage.

Conclusion

The presented GC-MS/MS method demonstrates robust performance for the determination of 17 organotin compounds in beverages, achieving low detection limits, excellent linearity, and reliable recoveries, making it suitable for routine monitoring and regulatory compliance.

References

1. Wang Xiuping et al. Development of an analytical method for organotin compounds in fortified flour samples using microwave assisted extraction and normal-phase HPLC with UV detection. Journal of Chromatography B, 2006, 843: 268-274.
2. Julien H. et al. Analytical advances in butyl-, phenyl- and octyltin speciation analysis in soil by GC-PFPD. Talanta, 2008, 75: 486-493.
3. Mino Y. et al. Determination of organotin in human breast milk by gas chromatography with flame photometric detection. Journal of Health, 2008, 54(2): 224-228.
4. David F., Sandra P., Wylie P.I. Improving the Analysis of Organotin Compounds Using Retention Time Locked Methods and Retention Time Databases. Agilent publication 5988-9256E.