Sample Flow Path - GE Sievers InnovOx Operation And Maintenance Manual

Chapter 2: System Description

Sample Flow Path

In the Online mode, the InnovOx On-Line TOC Analyzer can monitor up to two sample streams, or in the optional
5-stream configuration, it can monitor up to five sample streams.
Additionally, a 40-mL vial filled with sample can be inserted into the vial port for analysis in the Grab mode.
The Analyzer makes measurements in four concentration ranges: Up to 1,000 ppm, Up to 5,000 ppm, Up to
20,000 ppm, and Up to 50,000 ppm. In the 'Up to 1,000 ppm' range, the Analyzer measures concentrations up to
1,000-ppm organic carbon (NPOC or TOC) or 100 ppm IC. The sample is diluted with an equal volume of low-TOC
dilution water and reagents. In the 5,000-ppm range, the sample is diluted by a factor of 5:1. The sample is
diluted by a factor of 20:1 in the 20,000-ppm range, and the sample is diluted by a factor of 50:1 in the 50,000-
ppm range.
A measurement of a new sample begins with a "fast flush" which involves pumping sample into the Sample
Handling Module by its peristaltic pump. Next, reagents are drawn into the sample coil in the Sample Handling
Module by the syringe pump. Normally the syringe is empty and the sample coil contains dilution water. When
the reagents are drawn into the sample coil, the syringe fills with a volume of dilution water that equals the
volume of reagents to be used in the measurement. 6 M phosphoric acid (H PO ) or 3M hydrochloric acid (HCl)
3 4
(referred to as Acid in the user interface) is drawn into the sample coil first, followed by the sodium persulfate
(Na S O ) reagent (referred to as Oxid or Oxidizer in the user interface).
2 2 8
The purpose of the acid is to reduce the pH to 2 or less; this converts any carbonate or bicarbonate salts to CO .
2
The volume of the acid reagent that will be used in the analysis is determined by the Acid % setting. A value of
1% means that the volume of acid reagent will be 1% (V/V) of the total solution volume that later will be
contained in the sparging chamber.
The oxidizer has a concentration of 30% (W/V). The volume of the oxidizer reagent to be mixed with the other
solutions in the sparging chamber is determined by the Oxid % setting. A value of 15% means that the volume of
oxidizer reagent will be 15% (V/V) of the total solution volume that later will be contained by the sparging
chamber.
The syringe then empties, depositing the reagents into the sparging chamber. Next, the syringe fills with the
necessary volume of dilution water. The sample is then drawn into the sample coil. Because the sample only
enters the sample coil, the syringe and its three-way valve are protected against contamination by salts and
particulates in the samples. This greatly extends the life of the syringe and valve.
In the next step, the syringe pump empties the sample coil into the sparging chamber. The mixing bar in the
sparging chamber mixes the solution, and any particulates that were in the sample are suspended in the
homogeneous solution. Any IC in the sample is converted to CO by the acid. If NPOC is to be measured, the
2
solution is sparged with CO -free gas to remove the CO before the solution is transferred to the reactor.
2 2
The solution is not sparged when TC, IC, or TOC (TC-IC) is measured. However, IC is lost from the solution while it is
in the sparging chamber because the solution is acidic, and the IC is converted into volatile CO . The instrument
2
GE Analytical Instruments ©2013 54 of 238 DLM 68100-06 EN Rev. A