Measurement of Purgeable Organic Carbon (POC) by TOC-L

Importance of the Topic

The accurate determination of purgeable organic carbon (POC) in water sources is critical for ensuring drinking water safety and monitoring environmental contamination. POC analyses identify volatile organic compounds that can pose health risks or contribute to ecological pollution when present in solvents, fuels, or surface waters.

Objectives and Study Overview

This application note demonstrates the measurement of POC in tap water by spiking known amounts of an aqueous toluene solution. The study aims to validate the Shimadzu TOC-LCPH analyzer equipped with the POC measurement kit and to compare non-purgeable organic carbon (NPOC) and inorganic carbon (IC) levels in untreated tap water.

Methodology and Instrumentation

• Analyzer: Shimadzu TOC-LCPH Total Organic Carbon Analyzer
• POC Kit: Shimadzu purgeable organic carbon measurement kit
• Catalyst: Standard combustion catalyst
• Calibration: 3-point curve for POC (0, 1, 2 mgC/L); 2-point for NPOC (0–3 mgC/L) and IC (0–20 mgC/L)
• Sample Preparation: Tap water spiked with aqueous toluene solution at target POC concentrations (0.1–1.0 mgC/L)

Initial toluene solution TOC was confirmed at 86.2 mgC/L rather than the theoretical 100 mgC/L due to limited solubility.

Main Results and Discussion

Tap water naturally contained 0.743 mgC/L NPOC and 8.36 mgC/L IC, with no detectable POC. Spiking experiments showed excellent agreement between added and measured POC levels: 0.100 vs. 0.1 mgC/L, 0.295 vs. 0.3 mgC/L, 0.484 vs. 0.5 mgC/L, and 0.987 vs. 1.0 mgC/L. High accuracy and precision highlight the system’s suitability for low-level volatile carbon monitoring.

Benefits and Practical Applications

• Reliable quantification of volatile organic compounds in drinking water quality control
• Rapid, room-temperature sparging reduces sample handling complexity
• Integration with existing TOC workflows streamlines laboratory operations

Future Trends and Potential Applications

Advances may include automated online POC monitoring in distribution networks and coupling with mass spectrometry for compound-specific analysis. Miniaturized sensors and field-deployable POC analyzers could enable real-time water quality surveillance.

Conclusion

The Shimadzu TOC-LCPH analyzer with the POC kit delivers accurate, reproducible determination of purgeable organic carbon in tap water at sub-milligram levels. This method supports stringent quality control requirements for drinking water and environmental monitoring.