Improved HPAE-PAD method for determination of saccharides in atmospheric aerosol samples

Importance of the Topic

Biomass burning releases significant amounts of water-soluble organic carbon (WSOC) into the atmosphere, impacting air quality, human health, and climate. Saccharides such as anhydrosugars (levoglucosan, mannosan, galactosan), sugar alcohols, monosaccharides, and disaccharides serve as specific tracers to distinguish biomass burning sources from biogenic detritus. Rapid and accurate quantification of these markers in atmospheric aerosols is crucial for source apportionment and environmental monitoring.

Goals and Study Overview

This work aimed to develop a single-column HPAE-PAD method capable of separating and quantifying twelve saccharides in atmospheric aerosol samples within 20 minutes, without chemical derivatization.

Methodology and Instrumentation

• Chromatographic system: Thermo Scientific Dionex Integrion HPIC with electrochemical detection, controlled by Chromeleon™ CDS.
• Column: Dionex CarboPac PA300-4 µm (2 × 250 mm) with guard cartridge.
• Eluent: Electrolytically generated 15 mM KOH, flow rate 0.275 mL/min, column temperature 30 °C.
• Electrochemical cell: Gold working electrode on PTFE; Ag/AgCl reference electrode.
• Sample preparation: Passive diffusion on GF/A filters, sonication extraction; simulated matrix spiked with known saccharide levels.
• Calibration: Standards from 0.025 to 20 mg/L; linearity tested from 0.05–25 mg/L.
• Robustness testing: ±10% variations in flow rate, eluent concentration, and temperature; assessment of retention time, peak asymmetry, and resolution.

Main Results and Discussion

• Separation of twelve saccharides completed in under 20 min, with minimum resolution of 1.77 (mannitol/mannosan).
• Precision: RT RSD ≤ 0.6%, peak area RSD ≤ 3.6% (n = 3).
• Linearity: r² between 0.991 and 0.999 across each analyte’s range.
• Accuracy: Recoveries of 80–110% at 0.5 and 5 mg/L spike levels.
• Robustness: Method tolerant to minor parameter changes; fructose/sucrose resolution sensitive to an “oxygen dip” in baseline, adjustable by temperature or eluent concentration.

Benefits and Practical Applications

• Single-column, underivatized workflow reduces run time and complexity versus multi-column methods.
• Electrolytic eluent generation automates reagent delivery and minimizes waste.
• Rapid, reliable quantification supports routine aerosol monitoring in environmental research, QA/QC, and regulatory studies.

Future Trends and Opportunities

• Coupling HPAE-PAD with high-resolution mass spectrometry for broader WSOC profiling.
• Development of portable, field-deployed systems for near real-time aerosol analysis.
• Application of machine learning to saccharide marker datasets for advanced source apportionment.
• Extension of method to other polar organic tracers in atmospheric and environmental matrices.

Conclusion

The optimized HPAE-PAD method on a single CarboPac PA300-4 µm column enables fast, accurate, and robust separation of twelve key atmospheric saccharides in under 20 minutes. It offers excellent precision, linearity, and accuracy while simplifying the analytical workflow and reducing solvent consumption, making it ideal for routine environmental monitoring.

References

1. Simoneit B.R.T. et al. Environ. Sci. Technol., 38, 5939–5949 (2004).
2. Yttri K.E. et al. Atmos. Chem. Phys., 7, 4267–4279 (2007).
3. Medeiros P.M. et al. Atmos. Environ., 40, 1694–1705 (2006).
4. Elbert W. et al. Atmos. Chem. Phys., 7, 4569–4588 (2007).
5. Tominaga S. et al. Atmos. Environ., 45, 2335–2339 (2011).
6. Fu P.Q. & Kawamura K. Biogeosciences, 10, 653–667 (2013).
7. Linuma Y. et al. Atmos. Environ., 43, 1367–1371 (2009).
8. Barbaro E. et al. Atmos. Environ., 118, 135–144 (2015).
9. Engling G. et al. Atmos. Environ., 40 (Suppl. 2), 299–311 (2006).
10. Caseiro A. et al. J. Chromatogr. A, 1171, 37–45 (2007).
11. Zhang Z. et al. Atmos. Environ., 102, 290–301 (2015).
12. Yttri K.E. et al. Atmos. Meas. Tech. Discuss., 7, 125–147 (2014).
13. Nouara A. et al. Mar. Chem., 213, 24–32 (2019).
14. Thermo Fisher Scientific Application Note AN73009 (2022).