Tc - Tic Analysis - Hach BioTector B7000 User Manual

4.2.3.4

TC - TIC Analysis

BioTector TC - TIC analysis type is a combination of TC analysis and TIC analysis, which are run
simultaneously with two separate sample injections, in two different reactors (TC reactor and TIC reactor).
1. The oxygen carrier gas flow and the ozone generator are activated. Base reagent is injected into the
reactor and hydroxyl radicals are generated by exposing the base reagent to ozone. This reaction
phase is called Pre-Oxidation.
2. The oxygen carrier gas flow is stopped and an unfiltered sample is injected into the TC reactor with
the base reagent.
3. While there is no carrier gas flow, the volatile organic content if the sample is oxidized with hydroxyl
radicals. This reaction phase is called VOC Oxidation, as the oxidation of volatile matter is achieved
without being sparged.
4. While the VOC Oxidation takes place in the TC reactor, an unfiltered second sample is injected into
the TIC reactor of the BioTector.
5. An acid reagent is added into the TIC reactor and the oxygen carrier gas flow is activated to remove
the inorganic carbon. The carbon dioxide gas is sparged by the addition of the acid reagent and is
carried by the oxygen carrier gas and measured with an NDIR CO
displayed as TIC.
6. When both TIC phase and the VOC Oxidation phase are complete, the oxygen gas flow is activated
and the remaining Non-Purgeable Organic Carbon (NPOC) content of the sample in the TC reactor is
oxidized by the hydroxyl radicals during the Base Oxidation phase. The complete oxidation of organic
and inorganic compounds takes place and carbonates are formed.
7. When the Base Oxidation phase is completed, the carbonates are sparged in the form of carbon
dioxide gas by the addition of an acid reagent. The carbon dioxide gas is carried by the oxygen
carrier gas and measured with the NDIR CO
obtained from the TC analysis type represents the sum of TIC, NPOC and POC:
TC = TIC + NPOC + POC
8. When the TIC and TC analysis reactions are completed, both oxidized sample liquid in the TC reactor
and the sample inside the TIC reactor are discharged from the system with increased oxygen flow.
TOC result including the VOC (POC) is calculated from the difference between measured TC and TIC results:
= TC – TIC
TOC
v
As in the VOC systems, the TOC result displayed in TC - TIC systems includes the purgeable organic
element in the sample. In other words the TOC result displayed represents the sum of NPOC and POC:
TOC = NPOC + POC
v
BioTector analysis types are optional features. In order to be able to utilize TC - TIC
analysis type in BioTector, the system must be built with this option. For instance, a
system built with TIC & TOC, TC or VOC analysis options cannot be used for TC -
TIC analysis type. For TC - TIC analysis type to be possible in such systems,
mechanical changes, modifications in system configuration and system software will
be required.
2
analyzer. The result is displayed as TC. The TC result
2
analyzer. The measured result is
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