Measuring Methods; Tc Analysis; Toc Analysis - Endress+Hauser analytikjena multi N/C UVHS Operating Manual

multi N/C UVHS, multi N/C pharma UV
3.4

Measuring methods

3.4.1

TC analysis

3.4.2

TOC analysis

Digestion is carried wet-chemically via UV oxidation with or without the addition of the
strong oxidant, sodium persulfate Na
sample aliquot in the UV reactor, and it is irradiated with wavelength 185 nm; 254 nm
(UV-C) UV radiation At temperatures of up to 80 °C, any carbon compounds contained
are broken down into CO
phoric acid in the TIC reactor from an additional sample aliquot.
R-H → CO + H O
2 2
R-H - carbonic organic substance
The generated CO is expelled using inert gas (N
2
rosive gases, the measuring gas is added to the NDIR detector.
The concentration of CO
2
calculated from this signal sequence. The integral is proportional to the concentration of
the carbon in the measurement agent. Afterwards, the calculation of the carbon content
in the sample is performed via a previously determined calibration function.
The detection of several parameters can be combined in the multiWin control and anal-
ysis software.
TC: Total Carbon
In TC analysis, the total dissolved organic and inorganic bound carbon contained in the
sample is detected. Elemental carbon and solids are not digested.
The sample is dosed automatically into the reactor and digested, and the carbon dioxide
generated is detected.
TOC: Total Organic Carbon
In TOC analysis, the total organic bound carbon contained in the sample is detected.
TOC determination is carried out in the analyzer using the differential method which can
be described with the following formula.
TOC = TC – TIC
TOC - total organic carbon
TC - total carbon
TIC - total inorganic carbon
Two sequential measurements are used on one sample to determine TIC and TC. The
calculated difference is given as TOC. The differential method detects volatile as well as
non-volatile organic carbon compounds.
TOC analysis can be used when the sample contains easily purgeable organic substances
such as benzol, cyclohexane, chloroform, etc. If the TIC content of the sample is signifi-
cantly above the TOC content, TOC analysis should not be applied.
S O . Acidic persulfate solution is added to the
2 2 8
. The digestion of the inorganic carbon takes place using phos-
2
/Ar). After drying and removal of cor-
2
is detected several times per second. An integral over time is
Function and design
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