Zirconium analysis using automated photometric titration

Importance of the Topic

Accurate determination of zirconium in acidic aqueous matrices is critical for quality control across nuclear, chemical, ceramics, and catalyst industries. Automated photometric titration with EDTA and an optical detector enables fast, reliable analysis, minimizing human error and ensuring compliance with stringent purity requirements.

Goals and Study Overview

This application note (T-148) describes a fully automated method for quantifying zirconium in pH 1 aqueous samples. The protocol employs direct titration with 0.1 mol/L Na2EDTA using Eriochrome Cyanine R as the indicator and photometric endpoint detection at 520 nm.

Methodology and Instrumentation

Sample Preparation and Reagents:

• No complex sample preparation required—5 mL of zirconium solution (0.05 mol/L) is diluted with 90 mL deionized water
• Add 5 mL of pH 1 buffer and 1 mL of 0.4 g/L Eriochrome Cyanine R indicator solution
• Titrant: 0.1 mol/L Na2EDTA solution

Titration Parameters:

• Mode: MET U
• Volume increment: 0.05 mL
• Stirring rate: 8
• Pause before reading: 30 s
• Signal drift limit: 20 mV/min
• Equivalence point criterion: 15 mV using greatest slope detection
• Stop volume: 7.5 mL

Key Instrumentation:

• 907 Titrando controller
• 815 Robotic USB Sample Processor XL
• 786 Swing head and 6.1458.010 titration head
• Dosino dosing units (5, 10, 50 mL)
• Optrode photometric sensor (520 nm)
• Disposable 200 mL PP beakers

Main Results and Discussion

Six replicate titrations yielded a mean zirconium concentration of 4.323 g/L with a relative standard deviation of 0.87 %. The photometric endpoint provided clear, reproducible signals, confirming the stoichiometric reaction between Zr4+ and EDTA. The automated setup minimized manual intervention and delivered consistent performance.

Benefits and Practical Applications

• High precision and accuracy (RSD <1 %)
• Fully automated workflow reduces operator time and potential errors
• Minimal sample preparation and reagent usage
• Suitable for routine quality control of zirconium in industrial and research laboratories

Future Trends and Potential Applications

Emerging developments may include integration of flow injection analysis for higher throughput, adaptation to complex sample matrices (e.g., alloys, environmental waters), use of advanced optical sensors or alternative indicators to lower detection limits, and seamless data connectivity with laboratory information management systems (LIMS).

Conclusion

The automated photometric EDTA titration method outlined in Application Note T-148 offers a robust, efficient approach for zirconium analysis in acidic solutions. Its combination of ease of use, reliability, and automation makes it well suited for modern analytical laboratories.

References

No additional literature references were provided in the original application note.