Chemical Processes & Instrument Development: Instruments

Total Organic Carbon (TOC)

TOC instrument
TOC instrument in the laboratory

Principle of the Measurement

Catalytic conversion of all carbon species, including CO and CH4, to CO2 and detection either by non-dispersive infrared (NDIR) detection or cavity-ring down spectroscopy (CaRDS).

Species Measured

All C-containing species. The method has been verified for a range of organic compounds with a variety of functional groups.

Time Response

2-10 seconds

Detection Limit

Precision on 10s data ±5 to 10ppbC


± (2% + 10ppbC)


This instrument has been used for the calibration of VOC sources including gas and aerosol particle phases.


James Roberts

Key Publications

Veres, P., J. Gilman, J.M. Roberts, W. Kuster, C. Warneke, I.R. Burling, and J. de Gouw, Development and validation of a portable gas phase standard generation and calibration system for volatile organic compounds, Atmospheric Measurement Techniques, doi:10.5194/amt-3-683-201, 2010.

Stockwell, C.E., R.A. Washenfelder, A. Kupc, B. Witkowski, R.K. Talukdar, Y. Liu, V. Selimovic, K.J. Zarzana, K. Sekimoto, C. Warneke, R.J. Yokelson, A.M. Middlebrook, J.M. Roberts, Characterization of a catalyst-based conversion technique to measure total particle nitrogen and organic carbon and comparison to a particle mass measurement instrument, Atmospheric Measurement Techniques, doi:10.5194/amt-11-2749-2018, 2018.