Nonylphenol, Bisphenol A, 4-tert-Octylphenol, Nonylphenol Monoethoxylate, and Nonylphenol Diethoxylate on the Rxi®-5Sil MS by ASTM D7065-11 (Constant Flow)

Significance of the Topic

Nonylphenol and related alkylphenols are priority pollutants widely detected in water and industrial effluents. Accurate quantification of these endocrine disrupting compounds is crucial for environmental monitoring and regulatory compliance.

Objectives and Overview of the Study

This work demonstrates a gas chromatographic mass spectrometric method based on ASTM D7065-11 for simultaneous determination of nonylphenol, 4-tert octylphenol, bisphenol A and their ethoxylated derivatives. The approach aims to achieve rapid separation, reliable quantitation and constant peak shapes using a constant helium flow regime.

Methodology

• Sample preparation: Standards dissolved in dichloromethane and spiked with deuterated internal standards
• Injection: 1 microliter split injection (10 to 1) at 290 °C with a wool-lined liner
• Oven program: 50 °C hold for 2 minutes, ramp at 10 °C per minute to 320 °C, hold for 5 minutes
• Chromatographic column: Rxi-5Sil MS 30 meter by 0.25 millimeter by 0.25 micrometer
• Carrier gas: Helium constant flow at 1.44 milliliters per minute

Instrumentation

• Gas chromatograph: Agilent 7890B GC
• Mass spectrometer: Agilent 5977A MSD operating in full scan mode from 45 to 500 amu at 0.8 scans per second
• Transfer line temperature 290 °C, ion source 325 °C, quadrupole 150 °C, solvent delay 3 minutes
• Electron ionization and daily tune with DFTPP standard

Principal Results and Discussion

Chromatograms show baseline resolution for ten components including isotopic standards. Retention times ranged from 13.6 minutes for acenaphthene D10 to 23.4 minutes for chrysene D12. On column amounts varied between 2.5 and 64 nanograms. Constant flow operation maintained uniform peak widths across the gradient.

Benefits and Practical Applications of the Method

• Fast analysis time with complete separation in under 25 minutes
• Enhanced reproducibility and consistent peak shape using constant flow
• Applicable for environmental monitoring of endocrine disruptors
• Suitable for routine QA QC in industrial laboratories

Future Trends and Potential Applications

Integration with high resolution or tandem mass spectrometry could improve selectivity for complex matrices. Automated sample introduction and miniaturized GC systems may enable high throughput screening in field or remote settings. Data analytics and chemometric tools can further enhance quantitation accuracy and limit of detection.

Conclusion

The presented GC MS method following ASTM D7065-11 provides a robust, rapid and sensitive approach for quantifying nonylphenol, bisphenol A and related ethoxylates. Constant flow operation ensures uniform chromatographic performance making the method well suited for environmental and industrial applications.