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SCA-130-302

■ Result
The duplicate NPOC determination of a nitric
acid produced the following results:

NPOC RSD
Sample
[mg/l] [%]
Nitric Acid 36,9 1,4
(69%)
Nitric Acid
(69%) 33,4 3,0

To investigate this matrix influence, an
additional dilution (1:10) of a 69% nitric acid ■ Recommended Analyzer / Configuration
solution was carried out and a potassium
hydrogen phthalate stock solution was TOC-L CPH with normal sensitive Catalyst
subsequently added to increase the NPOC
content by 5 ppm. (Note: This corresponds to B-Type-Scrubber
an increase to 50 ppm for the 1:10 dilution). OCT-L (8-port Sampler)

NPOC RSD
Sample
[mg/l] [%]
Nitric Acid (69%) 25,1 1,3
Nitric Acid (69%)
Spiked with 50 ppm 76,2 1,8
KHP

The use of suitable gas washers (scrubbers)
enables reproducible TOC measurements in
concentrated nitric acid.