Measurement of TOC in Electroplating Solution by TOC-L CSH

Importance of the Topic

Organic additives in nickel and copper electroplating solutions play a critical role in bath performance and final coating quality. Monitoring total organic carbon (TOC) provides a direct measure of these additives and helps maintain consistent plating conditions.

Study Objectives and Overview

This study evaluates the Shimadzu TOC-LCSH combustion catalytic oxidation analyzer for accurate TOC measurement in high-salt nickel sulfamate plating solutions. The analysis includes fresh bath measurements, controlled spiking with potassium hydrogen phthalate at 50 and 100 mgC/L, and examination of used industrial solutions.

Methodology and Instrumentation

The Shimadzu TOC-LCSH analyzer integrates combustion catalytic oxidation and an automatic dilution unit to handle samples with high salt concentrations. Key operating parameters:

• Analyzer: Shimadzu TOC-LCSH
• Catalyst: Standard sensitivity
• Injection volume: 100 µL
• Measurement mode: NPOC (TOC by acidification and sparging)
• Calibration: Two-point using 0–5 mgC/L potassium hydrogen phthalate solutions adjusted to pass through the origin
• Sample dilution: 50-fold with distilled water

Main Results and Discussion

Spike tests on the fresh plating solution showed corrected TOC results of 23.8 mgC/L for the unspiked sample, and recoveries of 74.0 mgC/L and 122 mgC/L for 50 mgC/L and 100 mgC/L spikes respectively, aligning closely with expected values. Measurements of used nickel plating baths revealed increased TOC levels of 33.8 mgC/L and 65.8 mgC/L, confirming organic buildup over production.

Benefits and Practical Applications

Accurate TOC quantification enables proactive control of organic additive concentrations, optimizing plating bath life, ensuring consistent coating properties, and reducing downtime for bath maintenance.

Future Trends and Potential Applications

Advancements may include integration of inline TOC sensors for real-time monitoring, coupling TOC data with process analytics and machine learning for predictive maintenance, and extending the method to other high-salinity industrial processes.

Conclusion

The Shimadzu TOC-LCSH analyzer demonstrates robust performance for measuring TOC in high-salt electroplating solutions, offering precise, automated dilution capabilities that support quality control in plating operations.

References

No external references were provided in the original document.