COULOMETER UIC CM5015

Owned by jr_suhonen
Last updated: Oct 10, 2023
2 min read

Sep 10, 2023 Coulometer software was occasionally timing out before carbonate in the samples had time to react with the added acid and reach the cell. The software’s original parameters checked the slope of the ‘carbon graph’ against the slope threshold of 0.1 after 60 counts. In some cases this was not enough time for the carbonate to evolve into CO2. Tim Blaisdell extended this period to 120 counts. This new edit in the analysis parameters seems to function better for samples with low carbonate and carbonate species that require longer reaction times (e.g. dolomites).

Mar 16, 2022 Shortly after making a cell, the transmittance value started slowly dropping close to zero. Another cell cell was made, and the same thing happened. The plastic ring holding down the bulb was found to be loose, and tightening the ring resolved the issue.

Jul 20, 2021 During cell setup, the value that is supposed to be between 2700 and 4000 is still above 4000. It is not necessary to do anything about this. The coulometer has been tested several times and is working perfectly fine. The check standards come out within 2% from 100% every time. 

Sep 7, 2019 When running samples for the JR Academy the coulometer cell current would not revert to 0.0 after a measurement was "finished", which meant the µg C titrated would increase perpetually. The cell current ranged from 0.1-0.9. The ETs had to check several voltage setpoints on one of the interior circuit boards to verify lamp voltage was within the required limit of 2.45 V. It was reading ~2 V, so they adjusted the onboard potentiometer RP1 to within setpoint. The onboard potentiometer RP3 was reading ~9.3 V, from a required 9.60 V DC max, so it was not adjusted. The UIC technical bulletin which explains how to check the circuit boards (TB #70) is listed on this page with the other Coulometer references.