Measurement of Oil Residues on Metal Pipes Using the TOC Solid Sample Measurement System

Significance of the Topic

Accurate assessment of residual metalworking fluids on machined parts is crucial for product quality and reliability. Organic contaminants such as oils and surfactants can compromise performance in industries ranging from automotive to aerospace.

Objectives and Overview

This study demonstrates the use of a TOC solid sample measurement system combining the Shimadzu TOC-L Total Organic Carbon Analyzer and SSM-5000A Solid Sample Combustion Unit to quantify oil residues directly on stainless steel pipe surfaces without extraction steps.

Methodology and Instrumentation

• Sample Materials: Stainless steel pipes (1.5 mm O.D.) in two states: untreated (Sample A) and cleaned with laboratory detergent and water (Sample B).
• Instrumentation: Shimadzu TOC-LCPH analyzer, SSM-5000A combustion unit (900 °C catalytic oxidation), 400 mL/min O₂ carrier, short optical cell configuration.
• Calibration: Single-point using 20 μL of 1 % carbon glucose solution on heat-treated quartz wool.
• Measurement Procedure:
  1. Cut 3 cm pipe segments with ethanol-cleaned pliers.
  2. Weigh segments in the SSM-5000A sample boat.
  3. Initiate total carbon (TC) measurement via combustion and CO₂ detection.

Main Results and Discussion

Analysis revealed 20.76 ppm carbon on untreated surfaces (Sample A) versus 1.79 ppm after cleaning (Sample B). The high sensitivity and direct combustion approach enable clear differentiation of surface contamination levels and quantification of cleaning efficacy.

Benefits and Practical Applications

• Eliminates complex sample preparation by direct solid combustion.
• Provides rapid, reproducible quantification of organic residues for quality control.
• Applicable to diverse solid substrates in manufacturing and maintenance workflows.

Future Trends and Possibilities

Enhancements may include automated sample handling, expanded calibration strategies, and coupling with surface mapping techniques to visualize contamination distribution. Broader applications could span semiconductor wafer inspection and polymer-coated components.

Conclusion

The TOC solid sample measurement system offers a robust, straightforward method for detecting and quantifying oil residue on metal surfaces, supporting reliable quality control and process optimization in metalworking industries.

Reference

Shimadzu Corporation. Application Note LAAN-A-TC-E037. First Edition: August 2017.