Page 11 - 2_Pharmaceutical industry
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Sum parameter – Total Organic Carbon
TOC determination in ultra pure water with
wet chemical oxidation
SCA-130-205
The quality of ultra pure water is of crucial the resulting CO 2 using an NDIR detector.
significance in a large number of application Wet-chemical oxidation uses a combination
areas such as monitoring of water quality in of UV irradiation and persulfate oxidation.
water treatment plants, and in industries such Both methods are suitable for TOC
as chip manufacture or pharmaceutical determination in ultrapure water.
production. Determination of Total Organic
Carbon (TOC) is playing an increasingly The EP 2.2.44 guidelines do not specify any
important role in quality control. particular oxidation technique for TOC
determination. However, the TOC systems
must differentiate between inorganic and
organic carbon. This can be carried out via
removal of the inorganic carbon species
(NPOC method), or using a separate
determination (difference method). The limit
of detection for TOC should be at least 0.05
mg carbon/L. Applicability of the method must
be determined via a system suitability test.
■ TOC-V WP with wet chemical oxidation
The TOC value indicates whether ultra pure The fundamental technique of the TOC-V
water still contains any organic contaminants. WP/WS analyser is powerful oxidation via the
TOC determination is fast and accurate and combination of sodium persulphate and UV
is defined in the European Pharmacopoeia oxidation at 80 °C. These features guarantee
(EP) as a control parameter for WFI-water that all dissolved carbon species will be
(water for injection). detected. An automatic reagent preparation
function eliminates possible contamination of
■ TOC determination in ultra pure water the reagent solution and minimizes the blank
Two oxidation techniques are now commonly value of the instrument. These features,
used in TOC analysis: catalytic combustion together with the high injection volume (up to
and wet-chemical oxidation. In catalytic 20.4 mL) and the highly sensitive NDIR
combustion, carbon compounds are detector, result in extremely low detection
converted to CO 2 using high temperatures limits and excellent reproducibilities in the low
and a catalyst, with subsequent detection of ppb-range.
