Raman water sensitivity fail

Dear Agilent Community.


We have a Cary Eclipse fluorescence spectrophotometer (part number 02-101669-00, serial number EL 0604-3601) that is failing the Raman water sensitivity tests at both 350 and 500 nm excitation.


It passed all the tests when a new lamp was installed in 2016.


Is this a indication that it may be time for a new lamp?


Is there a counter that logs the lamp hours?


Is there a test specifically to determine the performance of the lamp?


We're using WinFLR 1.2 (147) under Windows 10 32-bit.




  • Agielnt recommends using the water filled cuvette for signal-to-noise measurements of Raman band of water, part number:6610021800.

    Also align the lamp; see the Help section on maintenance for isntructions.

  • Thanks for the feedback.


    I have re-optimized the lamp alignment, but I didn’t get much (if any) improvement.


    I also made some adjustments to the sample position, which I think helped a little.  I think some users have been fiddling with the sample position.


    The Raman sensitivity test is now passing with 500 nm excitation (597:1, reference 500:1), but still failing with 350 nm excitation (528:1, reference 750:1).


    The lamp is almost 1000 hours old.


    Is there a recommended lifetime for the Cary Eclipse lamps?  They are not just the lamp.  They are the entire housing.




  • I had a similar problem. A two-step procedure helped me.

    First I cleaned all the mirrors and windows in the excitation and emission compartments. To do this, remove the plastic cover from the instrument, and then, after unscrewing the screws, remove the black metal cover plate. The mirrors in my device were covered with dust accumulated over 7 years. I was unable to blow off this dirt with compressed air. Therefore, I used methanol and  optics cleaning paper. Be very careful as paper can scratch the surface of the mirrors. But I think that light scratches are a minor issue compared to the loss of reflectivity from dirt.

    The second stage was the alignment of the focusing mirror in front of the emission monochromator.  The alignment of the lamp and cuvette holder had already been performed earlier according to the user's manual. I put a diffuser in the cuvette holder. In the Align program, I set  both monochromators at 540 nm and the excitation slit at 1.5 nm. The emission slit was set to a value that does not yet saturate of the PMT. Since the monochromator slit is horizontal, I only adjusted the mirror in the vertical plane. A 2.5mm L-shaped hex wrench was needed for alignment. I shortened the working arm of my wrench so that it is more convenient to insert it into the screw in the confined space under the cover.

    The described procedure improved the SNR for the Raman water at 350 nm from 151 to 976.

    I hope my experience will help you.

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