Highly Sensitive and Specific GC-MS/MS Method for the Analysis of Boron in Drinking Water and Other Beverages

Importance of the Topic

Boron is a trace element crucial for bone health and plant growth, yet excessive exposure can adversely affect development and reproduction. Accurate quantification of boron in drinking water and beverages is essential for regulatory compliance and public health.

Objectives and Study Overview

This study describes a highly sensitive and selective gas chromatography–tandem mass spectrometry (GC-MS/MS) method for measuring boron in drinking water and complex beverage matrices. The approach leverages derivatization, advanced inlet technology, and multiple reaction monitoring (MRM) to achieve low detection limits and robust matrix tolerance.

Methodology and Instrumentation

• Derivatization: Boric acid is reacted with triethanolamine (0.5% w/v in acetonitrile) at 50 °C for one hour, then dried and reconstituted in ethyl acetate.
• Gas Chromatography: Agilent 7890A GC equipped with an HP-5ms column (15 m × 0.25 mm × 0.25 μm), temperature ramp from 100 °C to 280 °C at 35 °C/min.
• Injection System: Multi-Mode Inlet (MMI) operated in pulsed splitless cold-injection mode, 1 μL injection volume, ultimate-union backflush to remove high-boiling matrix compounds.
• Mass Spectrometry: Agilent 7000B triple quadrupole, electron ionization at 260 °C, MRM transitions 126→98 and 126→86 with optimized collision energies for high selectivity.

Main Results and Discussion

The method achieved a limit of detection of 2 ppb and a limit of quantitation of 15 ppb in a tomato-based vegetable matrix, significantly outperforming GC-MS SIM (80 ppb LOQ) and ICP-OES (150 ppb LOQ). Backflush dramatically reduced matrix carryover and preserved column longevity, while cold splitless injection enhanced signal-to-noise ratios. The targeted MRM transitions eliminated isobaric interferences in challenging samples.

Benefits and Practical Applications

The protocol offers enhanced sensitivity and specificity for boron analysis in water and beverages, improved matrix tolerance via backflush and MS/MS discrimination, and reduced instrument maintenance through minimized contamination.

Future Trends and Potential Applications

Future developments may include automated derivatization, application to soil and plant extracts, exploration of alternative derivatizing agents to further lower detection limits, and integration with online sampling for real-time environmental monitoring.

Conclusion

This GC-MS/MS method delivers a rapid, robust, and highly selective tool for quantifying boron at part-per-billion levels in complex matrices, supporting regulatory compliance and quality control in water and beverage analysis.

References

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