Sensitive Determination of 17 Organotin Compounds in Beverages Using Agilent 7890A / 7000 Series GC-MS/MS System

Significance of the topic

Organotin compounds (OTCs) are widely used as preservatives, biocides and stabilizers in coatings, plastics and pesticides. Their persistence, bioaccumulation and endocrine‐disrupting potential have raised concerns about human exposure via the food chain. Sensitive monitoring of OTC residues in beverages is essential to ensure consumer safety and regulatory compliance.

Objectives and Overview

The study aimed to develop and validate a rapid, precise and highly sensitive method for simultaneous determination of 17 OTCs in various beverages. Utilizing the Agilent 7890A gas chromatograph coupled with a 7000 Series triple-quadrupole mass spectrometer in MRM mode, the research evaluated method performance and applied it to real samples to assess contamination levels.

Methodology

• Sample preparation: 10 mL beverage aliquot, addition of methanol and ultrasonic extraction (10 min).
• Derivatization: Add acetate buffer (pH 4.5) and NaBEt₄ reagent in ethanol, shake for 30 min.
• Liquid–liquid extraction: Add water, extract organotin derivatives into 1 mL hexane, vortex and separate phases.
• Instrumental analysis: Inject 2 µL (splitless) onto an Agilent HP-5 MS UI column (30 m×0.25 mm×0.25 µm).
• GC temperature program: 50 °C (1.5 min), ramp at 10 °C/min to 300 °C, hold 1 min; helium carrier at 1.1 mL/min.
• MS/MS parameters: EI source (70 eV), source temp 230 °C, interface 280 °C; collision gas nitrogen (1.5 mL/min), quench gas helium (2.25 mL/min), solvent delay 2 min; MRM transitions optimized per compound.

Instrumentation

• Agilent 7890A Gas Chromatograph
• Agilent 7000 Series Triple-Quadrupole Mass Spectrometer

Results and Discussion

• Chromatographic separation of 15 out of 17 OTCs was achieved within 22 min; coelution of two compounds was resolved by unique MRM transitions.
• Calibration curves over 1–200 µg/L (seven levels) showed excellent linearity (R² > 0.995 for all analytes).
• Method recoveries at spiked levels (10 and 50 µg/L) ranged from 70 % to 120 %, with RSDs below 10 %.
• Analysis of 11 commercial beverages detected dimethyltin and monobutyltin in one sample at trace concentrations, demonstrating real‐world applicability.

Benefits and Practical Applications

• The GC-MS/MS MRM approach eliminates background interferences and delivers high sensitivity and selectivity.
• Short analysis time and robust sample preparation support routine quality control in beverage and food testing laboratories.
• Quantitative performance meets regulatory requirements for trace‐level monitoring of OTC contamination.

Future Trends and Applications

• Integration with automated sample preparation and online derivatization to increase throughput.
• Extension to other food and environmental matrices for broader organotin speciation studies.
• Advancements in high‐resolution MS and miniaturized GC systems for ultra‐trace analysis.
• Development of multi‐residue methods combining organotins with other emerging contaminants.

Conclusion

The optimized Agilent GC-MS/MS method enables rapid, accurate and sensitive determination of 17 organotin compounds in beverages. Its robust performance, demonstrated linearity, recovery and precision, along with successful application to real samples, highlights its suitability for routine monitoring and safety assessment.