Teledyne 6750 - Total Organic Carbon analyzers - Manual (Page 24)

Theory of Operation Model 6750
Teledyne Analytical Instruments 12
actual measurement of the TIC, a more accurate TOC is achieved since
(TOC = TC - TIC).
“TOC-Direct” mode is preferred for accuracy when no or little
volatiles are present. In this mode, the carbonate-free sample is
extracted from the organic carbon reactor and measured directly as
TOC. Pump (P –1) continuously introduces the carbonate-free sample
to the reactor. No valves or complicated injection mechanisms are
required. The remaining organic carbon is oxidized to CO
2
in the
reactor. The resultant gaseous stream is directed to a gas/liquid
separator and then to the NDIR. The CO
2
gas is analyzed by the
infrared analyzer (NDIR) as a direct correlation of Total Organic Carbon
(TOC).
A computer controls all functions and outputs. A “Touch Screen”
provides operator interface and a paperless chart recorder utility.
Figure 2-6: Sample Handling for TOC -Direct