GE Sievers 900 Series, Operation And Maintenance Manual

Page: 58 / 236

GE Analytical Instruments ©2009 58 of 236 DLM 90488-01 Rev. A
Major Accessories and Configurations
Inorganic Carbon Remover (ICR) Unit
For water samples containing high levels of inorganic carbon (IC) compared to the TOC levels (such
as some municipal water systems, groundwater supplies, and RO permeates), improved accuracy
in TOC measurements can be achieved by removing most of the IC prior to TOC measurement. The
Sievers 900 ICR consists of a vacuum degassing module, a vacuum pump, and a carbon and soda
lime trap. In operation, the water sample is introduced into the Analyzer and acid is added to the
sample as usual. The stream is then directed through the vacuum-degassing module. Carbon
dioxide produced from the reaction of bicarbonate and carbonate with acid is removed from the
sample stream by the vacuum. The sample is returned to the Analyzer and is directed by the stream
splitter for measurement of IC and TC. Approximately 99% of the IC is removed at concentrations
up to 25 ppm. The activated carbon/soda lime trap prevents contamination of the sample stream
from organic compounds and CO
2
in the atmosphere.
Typically, if the TOC is 10% or less of the IC concentration, the ICR will be required. For example, if
the IC is 1 ppm, then use the ICR if the TOC is 100 ppb or less for accurate TOC measurements. The
Analyzer will calculate the TOC/IC ratio for each measurement; if this ratio is less than 0.1, a
warning message will be issued and written to the Warnings/Errors list.