Discussion Category: Atomic Absorption
Replicate measurements with FIAS 400
I'm doing a mercury cold vapour analysis with a Perkin Elmer FIAS 400 equipped with an AS90 autosampler and Aanalyst 100 spectrometer. The reducing solution is 1.1% SnCl2 in dilute HCl. For all of my calibration standards and sample measurements the first sample is consistently higher than the rest by a factor of about 2. I've tried changing the fill time on the FIAS to 20s from 10s, but am getting the same results, so I don't think the problem is with the sample loop not filling completely on replicates subsequent to the first. Any other ideas?