WCPS: Evaluation of a novel nebulizer using an inductively coupled plasma optical emission spectrometer

Significance of the Topic

Advances in nebulizer technology directly impact the performance of inductively coupled plasma optical emission spectrometry (ICP-OES). A robust universal nebulizer that maintains high sensitivity, tolerance to dissolved salts, strong acids and organic solvents, and operates efficiently over varied flow rates can streamline analytical workflows, reduce maintenance, and improve data quality across environmental, industrial, and research laboratories.

Objectives and Study Overview

This study evaluates a novel flow-blurring nebulizer (FBN) fabricated from inert polymeric materials and compares its performance against a conventional concentric glass nebulizer (GCN) and a commercial polymeric nebulizer (OneNeb). Key performance metrics include detection limits, transport efficiency, long-term stability, and tolerance to high total dissolved solids (TDS) and organic solvents.

Methodology and Instrumentation

An Agilent 725 Series ICP-OES with a radially viewed plasma and custom CCD detector covering 167–785 nm was employed. Operating parameters were:

• RF power: 1.3 kW
• Plasma gas flow: 15 L/min Ar
• Auxiliary gas flow: 2.25 L/min
• Spray chamber: single-pass and double-pass glass cyclonic
• Torch: standard demountable with 0.38 mm quartz injector
• Nebulizer flow: 0.7 L/min
• Replicate read time (LoD): 30 s (10 replicates after 30 s stabilization)
• Stability test: 6 replicates at 10 s read time

The FBN design uses passive nebulization with capillary tubing extending to the tip where carrier gas and sample mix under precisely controlled geometry. This avoids low-pressure zones and constrictions, reducing blockage risk from high TDS or crystallizing salts.

Main Results and Discussion

Transport efficiency (TE) with the FBN reached 12.5–31.4% in aqueous solutions and 44.0–49.0% with organic solvents (ShellSol®, DiBK), significantly outperforming the GCN (6.1–12.8%). At flow rates as low as 40 µL/min, TE remained robust, indicating suitability for limited-volume samples.

Detection limits for 22 elements showed equivalent or superior performance of the FBN versus the GCN. Ratios of detection limits (FBN/GCN) exceeded 100% for most analytes, with notable improvements for elements such as Be (193%), Na (197%), Cu (183%) and Ba (162%).

Long-term stability tests over 12 hours in DiBK and ShellSol® demonstrated consistent signal performance without blockages or signal drift, contrasting with frequent clogs observed in GCN during extended runs.

High-TDS sample tolerance was on par with dedicated V-groove nebulizers, but with better precision and lower detection limits. The FBN also matched inert polymeric nebulizers in resistance to strong acids like HF.

Benefits and Practical Applications

• Universal applicability across a broad range of matrices (aqueous, high TDS, organic solvents, strong acids).
• Improved sensitivity and lower detection limits compared to conventional glass nebulizers.
• Enhanced long-term stability and resistance to blockage, reducing downtime and maintenance.
• Mechanical robustness minimizes damage from shocks.
• High nebulization efficiency at low uptake rates facilitates analysis of limited-volume samples.
• Cost-competitive with high-performance concentric glass nebulizers while replacing multiple specialized types.

Future Trends and Potential Applications

The FBN concept may drive the next generation of universal nebulizers, with potential developments including microfluidic integration for ultralow sample volumes, adaptation to other plasma spectroscopies, and further optimization of polymeric materials for even greater chemical resilience. Its versatility supports automated method development and high-throughput laboratories seeking simplified instrument configurations.

Conclusion

The flow-blurring nebulizer offers a genuine universal solution for ICP-OES applications, combining high sensitivity, broad matrix tolerance, mechanical durability, and low maintenance. By delivering superior detection limits, stable performance over extended use, and robust operation with challenging solvents and high TDS, the FBN can replace multiple specialized nebulizers, streamline workflows, and enhance analytical reliability.

References

• Moffett J., Russell G., Lener J.P. Evaluation of a novel nebulizer using an inductively coupled plasma optical emission spectrometer. Agilent Technologies, January 2011.