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Sum parameters – Total Organic Carbon
Combined TOC and TNb determination
in hydrogen peroxide solution (H2O2)
No. SCA-130-311
commercially available H2O2 solutions, creat-
Hydrogen peroxide (H2O2) is a mostly odor-
less, colorless liquid which could be described ing a wide range of available purity levels for
simply as water with an additional oxygen various applications.
atom attached. This additional oxygen atom is
The level of purity required in the various in-
keeping the molecule barely together in the
dustrial fields is becoming increasingly higher,
so-called peroxide bond, but defines its large
a strong example being the semiconductor in-
variety of uses in chemistry as a potent oxidiz-
dustry. To determine the purity of hydrogen
ing agent. As the only byproducts of its reac-
peroxide solutions, combined TOC and TNb
tions are water and oxygen, it can be consid-
measurement is an effective tool, as meaning-
ered environmentally friendly when used
ful results can be obtained within minutes.
properly.
■ TOC / TNb determination
In the following measurements, a 30% hydro-
gen peroxide solution was measured using a
Shimadzu TOC-L CPH with TNM-L module.
Calibration of the system was carried out using
the automatic dilution function within a range
of 10 – 50 mg/L TOC and 1 – 10mg/L TNb.
Calibration Curve
132,641
■ Economic importance of H2O2
80
Hydrogen peroxide is frequently used as a Area
bleaching agent of pulp, natural fiber and 40
chemical fibers in both industrial and house-
0
30
hold applications. In water treatment, in so 0 10 20 Conc[mg/L] 40 50 55
called UVOX-processes (UV and Oxidation),
Fig.1: TOC Multi-point calibration with dilution function
UV radiation causes the formation of hydroxyl
radicals that are used to decompose organic The undiluted hydrogen peroxide solution is
impurities in drinking water. Additionally, it is placed in the autosampler in septum-sealed
used in the synthesis of chemical materials, 40mL vials. The sample is then acidified and
pharmaceuticals, as rocket propellant, disin- sparged out to remove inorganic carbon and
fectant, in metal surface treatment and many CO2 using the external sparge kit (NPOC de-
more. termination). An undiluted aliquot of the sam-
Hydrogen peroxide tends to decompose into ple is injected onto a hot (720°C) platinum cat-
water and oxygen with increasing pH value, alyst. Organic substances are converted to
but especially when coming into contact with CO2 and detected using a NDIR detector. At
metal surfaces, causing a catalytic reaction. the same time, nitrogen compounds are con-
That is why stabilizers (organophosphorus verted to NO and detected by a chemilumines-
compounds and others) are being added to cence detector.
