Swab / Direct Combustion Analysis of Detergent Residue Using SSM-5000A

Importance of the topic

Cleaning validation in pharmaceutical manufacturing ensures that residues of previous products, detergents, and environmental contaminants remain below acceptable limits. Reliable detection of detergent residues supports product safety and regulatory compliance, particularly when insoluble residues challenge conventional rinse sampling techniques.

Objectives and study overview

This application note demonstrates the use of a swab/direct combustion total organic carbon (TOC) analysis method, employing Shimadzu’s TOC-VCSH analyzer with the SSM-5000A Solid Sample Combustion Unit, to quantify detergent residues on production surfaces.

Methodology and instrumentation

A swab sampling approach was adopted, where quartz silica fiber filter paper is used to wipe defined surface areas. Samples are placed in the SSM-5000A sample boat for direct combustion. Calibration was performed with a 30 μL injection of 1 % carbon glucose solution. Two test solutions were prepared:

• 1 % (v/v) laboratory-grade detergent solution in water
• 1000 mgC/L sodium dodecylbenzene sulfonate (SDBS) solution

Instrumentation:

• Shimadzu Organic Carbon Analyzer TOC-VCSH
• Solid Sample Combustion Unit SSM-5000A
• Advantec QR-100 quartz silica fiber filter paper (heat-treated at 600 °C)

Main results and discussion

Total carbon (TC) measurements for the liquid solutions yielded 1127 mgC/L for the detergent mix and 982.9 mgC/L for the 1000 mgC/L SDBS solution, demonstrating good repeatability. Recovery studies using the swab/direct combustion method showed recoveries of 100.4% for the detergent solution and 98.9% for SDBS, confirming accurate quantification without extensive sample preparation.

Benefits and practical applications

The swab/direct combustion TOC method provides:

• Rapid and direct quantification of carbon-based residues, including insoluble detergents
• Elimination of solvent extraction or enrichment steps
• High recovery rates compliant with regulatory guidelines (FDA, Japanese MHLW)

Future trends and possibilities

Potential developments include expanding the method to multi-component cleaning agents, integrating automated swab sampling, coupling with real-time data processing for on-site monitoring, and enhancing combustion units for higher throughput.

Conclusion

The combined swab/direct combustion approach with Shimadzu’s TOC-VCSH and SSM-5000A delivers a robust, accurate, and streamlined solution for cleaning validation of detergent residues in pharmaceutical environments.

References

No formal literature references were provided in the source document.