GE Sievers 900 Series - Gas Bubbles Are Present in Reagent Lines or Syringes; Ph of Sample Stream Is too High

GE Analytical Instruments ©2009 210 of 236 DLM 90488-01 Rev. A
• If water does not leak out the green restrictor tubing, the obstruction is in the tubing.
Connect the water bottle to the green restrictor tubing, remove the inlet cover from the
DI water reservoir, and gently flush water through the tubing. Again, carefully monitor
the water level in the DI water reservoir as you squeeze the water bottle. Reconnect the
restrictor tubing to the solenoid valve and resume normal operation.
17. If symptoms recur, contact GE Analytical Instruments Technical Support for assistance.
Gas Bubbles Are Present in Reagent Lines or Syringes
The presence of gas bubbles in the lines from the reagent containers to the syringe pumps and
from the syringe pumps to the stainless steel cross can cause erratic TOC readings. Turn off the
Analyzer and disconnect the power cord. Open the Analyzer case and inspect the 1/16" Teflon
tubing from the syringes. If you detect gas bubbles in the lines or a large (greater than 30 µL) gas
bubble in the syringe, reconnect the power cord, turn on the Analyzer, and perform a syringe flush.
For further information, see “Flushing the Reagent Syringes” on page 191.
pH of Sample Stream is Too High
If the pH of the sample stream is too basic (e.g., pH > 8), erratic readings and low TOC recovery may
be observed. Increase the acid flow rate by 1-2 µL/min and determine if this eliminates the
problem.
With the sample stream flowing and analysis taking place, tear off a strip of pH paper and hold the
paper in the waste stream, if accessible.
Compare the color of the paper with the pH color scale on the side of the pH paper container. If the
pH is not less than 2, not enough acid is being added to the sample stream. Possible reasons for
high pH include:
• The valve on the acid reservoir is closed.
• Acid flow rate is too low (see “Setting Reagent Flow Rates” on page 94 and increase flow
rate if necessary).
• Acid reservoir is empty or low (perform a visual check of the reservoir).
• Acid syringe is defective or not working (contact GE Analytical Instruments for instructions).