Chromatography Forum

Hello all,
We're considering one of the Corona CADs from ESA as a replacement for ELSD. I'd like to hear what anyone's day-to-day experience is with these; in terms of precision, stability of response throughout the run, robustness, maintenance, etc.
We've found the ELSDs to be a bit of a pain and I'm curious if the CAD really works much better.
Thanks for any info you can provide.

from what I've heard, the CAD's are a good deal more sensitive than ELS, however I cannot confirm. Why do you dislike your ELS?

Editorial content follows, please ignore if irrelevant =>I've found ELS to be a really handy tool to have in the lab. Mine has been rugged, reliable, and has exhibited better precision than I had been led to expect With a well optimized assay I can easily see 1-2% RSD's on system suitability runs. I've only ever had to pull the nebulizer for cleaning twice (since 2005) and have had to do nothing else beyond the normal annual PM...which is due in about 2 weeks and the beast was running fine this morning.

We frequently see enough drift in response such that bracketing standards don't pass.
I'll admit that we have some older ELSDs(>7-8 years) and the method has been around for a long time too. Couldn't say if it was well optimized to begin with (perhaps not given our experience!). I'm guessing the newer ELSDs are much better. Just out of curiousity, which instrument are you using? Do you run it with reversed phase or normal phase?

I'm currently using a Waters 2420, circa 2005, which I've found to be a workhorse. I use both reversed phase and normal phase, though the normal phase is primarily on amino supports, not bare silica. Some folks say that Sedex machines (I think) are more sensitive than the Waters unit, but I've had no problems with what I've tried to do.

I typically bracket standards and have never found significant drift in response. Using a quadratic fit and evenly spaced standards in my runs, I routinely exceed RSQ of 0.999...I can't quote std error from memory, sorry.

cCAD worked extremley well for some phospholipid separations I had to do, where ELSD gave us some of the same problems you described.

Thanks to both of you. I should mention that our ELSD method is for phospholipids too - perhaps they are particularly tricky. Nice to hear that the CAD was an improvement.