wtw PROTOC 200, Operating Manual

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Overview PROTOC 200
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Function The PROTOC 200 is used to continuously measure organic carbon
content (TOC = total organic carbon) in aqueous samples. The mea-
surement procedure consists of the following steps:
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A reagent is added to the sample. The reagent contains sodium per-
sulfate and nitric acid or ortho-phosphoric acid.
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The sample and reagent mixture is sparged with a carrier gas (usu-
ally compressed air or nitrogen). This removes inorganic carbon and
dissolved carbon dioxide. The remaining liquid contains only organic
carbon compounds.
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The remaining liquid is pumped into the reaction vessel.
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A strong ultraviolet light source in the reaction vessel promotes oxi-
dation of the organic carbon compounds by the persulfate. This pro-
cess produces carbon dioxide gas.
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Carrier gas flows in through the reaction vessel base and transports
the carbon dioxide through a gas drying system and on to an infra-
red carbon dioxide detector. The amount of carbon dioxide pro-
duced is directly proportional to the organic carbon content of the
sample.
The PROTOC 200 can also be used to determine the total carbon con-
tent (TC = total carbon). The sample and reagent mixture is pumped di-
rectly into the reaction vessel without prior sparging.
The measuring signal is transmitted to the controller. The controller is
equipped with a signal output used in the control of external processes.
The PROTOC 200 is calibrated by passing a standard solution through
the analyzer. The standard solution contains a known quantity of car-
bon. The IR detector is adjusted until the analyzer displays the correct
reading. Solenoids switch between the sample and the standard solu-
tion.
Measurement output Measuring signals can also be output to external equipment (e.g. re-
corder, PC) via a 4 - 20 mA or 0 - 10 VDC (selectable) analog output.