Chromatography Forum

I am using a Shimadzu HPLC with a RID-10A detector to analyze sugars using an ion-exchange column and water as a mobile phase. A week ago I tried running standard ethanol samples for a calibration curve and noticed that my baseline was fluctuating greatly with an upward drift even after extensive flushing of the reference and sample cells with my mobile phase (H2O). I also balanced the cells.
I read through the user manual and determined that the source of my baseline problems were probably due to cell dirtiness. I only use water and sugars in my HPLC analysis and therefore there might have been residual sugars left in the cell that left a film. Anyways, I attempted the cleaning procedure outlined in the user manual, which was 50 mL acetone , 100 mL H2O, and 50 mL of 0.1M nitric acid followed by extensive purging of my flow lines with H2O (i.e., left overnight). My flow rate was 0.500 mL/min and the pressure was consistent. After refilling the reference cell and balancing, there was a new issue.
Instead of baseline issues, the RID LED screen now displays the message "ALAM", which pertains to the Total Energy value of ~1600, when it should be from 6000-9000. This means that there is not enough light reaching the cell. The lamp has only been run for ~2400 hours and should not have to be replaced until about 20,000 hours. I also increased the Lamp Voltage from 3.89 to 5.00, which is the maximum recommended voltage.

Currently, I am trying another cleaning method using IPA (isopropyl alcohol), Ethanol:Chloroform (80:20), and IPA again followed by extensive flushing with H2O.
My flow rate again is 0.500 mL/min at room temperature. The cell temperature has always been 40 C.

Is there anything else I should try if this does not work, before ordering a new lamp?

hi, I have a same problem with you, how do you solve the problem,.

You may check the tubing connections to solenoid valves , which connected to reference and sample cells.
The fingertight fittings sometimes getting loose and leaking , this may cause baseline and energy problems.

You may check the tubing connections to solenoid valves , which connected to reference and sample cells.
The fingertight fittings sometimes getting loose and leaking , this may cause baseline and energy problems.

thanks for your help，i used flush the system with H2O for a week, and the system performs well，but i replaced the mobile phase(H20) with THF , the "alarm" appear again.

Hei! I am having the same issue. And a non-functioning solenoid valve would actually explain very well the things I am observing. Can you provide instructions on how to check the solenoid valve? Do I have to dissassemble the detector? How do you by-pass the solenoid valve?

Thanks in advance,
Anna