It is the most advanced instrument in the world for the thermal analysis of the carbonaceous content of aerosol samples collected on filters.
Thermal/optical carbon analysis is based on the preferential oxidation of OC and EC materials under different temperatures and atmospheres. A ~0.5 cm2 punch from a particle-laden quartz fiber filter (or other sample form) is heated in programmed temperature steps. Organic compounds are liberated under a non-oxidizing helium atmosphere at lower temperatures up to 580 °C, while EC is combusted in an oxidizing atmosphere with 2% O2 at temperatures up to 840 °C. The liberated carbon is oxidized to carbon dioxide (CO2) by heated manganese dioxide (MnO2), and the CO2 is quantified by an NDIR detector. Seven modulated diode lasers measure the reflectance from, and transmittance through, each filter at wavelengths from 405 to 980 nm.
Measurement Range: 0.05 to 750 µg carbon/cm2 (depending on carbonaceous composition)
Minimum Detection Limit (MDL):
Wavelengths: 405, 445, 532, 635, 780, 808, and 980 nm
Data Reporting Interval: 1 second
ENVIRONMENTAL OPERATING CONDITIONS
Temperature: 10 to 35°C
Relative Humidity: 0 to 90%, noncondensing
Sample oven: programmable from 60 to 900 °C with maximum heating rate 250 °C/minute
Oxidation oven: 900 °C
Temperature accuracy: ±5 °C or 1%, whichever is greater