Hach BioTector B3500s, Руководство пользователя

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Page 47
4.2.4 BioTector Analysis Types
BioTector TOC analyzer has four factory calibrated analysis types:
1. TIC & TOC (NPOC) Analysis: Total Inorganic Carbon & Total Organic Carbon (Non-Purgeable
Organic Carbon) Analysis
2. TC Analysis: Total Carbon Analysis
3. VOC (POC) Analysis: Volatile (Purgeable) Organic Carbon Analysis
4.2.4.1 TIC & TOC Analysis
1. An acid reagent (e.g. Sulfuric Acid) is added and the oxygen carrier gas flow is activated to remove
the inorganic carbon.
2. An unfiltered sample is injected into the BioTector reaction chamber (Mixer Reactor).
3. The carbon dioxide gas is sparged by the addition of the acid reagent and is carried by the oxygen
carrier gas and measured with a nondispersive infrared (NDIR) CO
2
analyzer. The result is displayed
as Total Inorganic Carbon (TIC). This reaction phase is called TIC phase.
4. Ozone generator is activated. A base reagent (e.g. Sodium Hydroxide) is injected and the sample is
then oxidized with hydroxyl radicals, a strong oxidizing agent, which is generated by exposing high
pH reagents to ozone. This reaction phase is called Base Oxidation phase. The complete oxidation of
organic compounds takes place and carbonates are formed.
5. After the Base Oxidation phase, 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
2
analyzer. The result is displayed as Total Organic Carbon (TOC). This
reaction phase is called TOC phase. The TOC result obtained from the TIC & TOC analysis type
represents the Non-Purgeable Organic Carbon (NPOC).
6. At the end of the reaction, the oxidized sample liquid is discharged from the reactor with increased
oxygen flow.
4.2.4.2 TC Analysis
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. An unfiltered sample is injected into the reactor of the BioTector with a low flow of oxygen carrier gas.
3. The volatile organic content of the sample is oxidized with hydroxyl radicals. This reaction phase is
called VOC Oxidation, as the oxidation of the volatile organic matter is achieved without being
sparged.
4. When the VOC Oxidation phase is complete, the oxygen gas flow and the ozone generator is
activated and the remaining Non-Purgeable Organic Carbon (NPOC) content in the sample is
oxidized by the hydroxyl radicals in Base Oxidation phase. The complete oxidation of organic and
inorganic compounds takes place and carbonates are formed.
5. When the oxidation processes are 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
2
analyzer. The result is displayed as Total Carbon (TC).
The TC result obtained from the TC analysis type represents the sum of TIC, NPOC and Purgeable
Organic Carbon (POC):
TC = TIC + NPOC + POC
6. At the end of the reaction, the oxidized sample liquid is discharged from the reactor with increased
oxygen flow.
BioTector analysis types are optional features. If the BioTector is built as a TIC & TOC
system only, modifications in the system configuration will be required for TC analysis to
be possible.