Waters 2487 Detector Fogging Problem

[gbalock]

Recently, we have encountered a problem that appears to be a problem with the grating in Waters 2487 detectors fogging with what our service guy tells us is an oily type substance. Have any of you seen this in your detectors?

[Mark Tracy]

I've never seen oily films, but I have seen cases where something in the lamp compartment photolyzes and deposits elsewhere. This can be accompanied by excess noise. Once it was something that etched the quartz lamp. I have also seen "UV burn" where traces of hydrocarbon photolyze into a tenacious film on optical windows, but that was an ICP/OES. Another time I saw gratings corrode in a humid environment.