An issue with signal intensity in 1260 infinity and 1260 infinity II FLD detector

Hello everyone,

I have a question regarding the 1260 infinity and 1260 infinity II FLD detector, recently I have noticed that the signal intensity in 1260 infinity II is almost twice as the 1260 infinity for the same sample concentration with the same PMT gain (=10), I replaced the flowcell of the two instruments and also replaced the lamp with a new one, but they did not have a significant effect on the signal intensity. Before appearance of the problem the difference of signal intensity between two instruments was less than 15 %.Is there any way to calibrate the signal intensity?


  • It is pretty normal to see differences in signal height with two different FLDs. Therefore, finding the best PMT value is part of method development and methods should not simply be transferred from one system to another. Signal height does not tell anything about sensitivity. In the end only determining S/N will tell you which FLD performs better.

    If you dislike the fact that two FLDs show differences in signal height, some correction can be done "cosmetically" by using the "Response Multiply Factor" from your CDS. I also suggest you read through FLD Scaling Range and Operating Conditions in the manual.

  • Thank you very much, it was helpful.

Was this helpful?