Ruta, Did you bake the GFF filters before you used them?
----- Original Message -----
From: "Ruta Bariseviciute" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Sunday, January 27, 2013 9:56 AM
Subject: [ISOGEOCHEM] Problems with GF/F filters measurements
> Dear All,
> I have problem with measurements of GF/F filters. My samples are
> freshwater lagoon sediments. Nitrogen isotope ratio +20‰. We have Delta V
> Advantage and FlashEA1112. Salt concentration in the samples is very law.
> I removed carbonates keeping filters in desiccators with concentrate HCl.
> After 4 hours I kept my filters in 50oC for about 24 hours. I always was
> using this method and didn’t have any problems. Can it be chlorine? Maybe
> I had to keep filters in fume hood for Cl evaporation? Or maybe may GC
> column is “tired”. I had cleaned GC column by increasing its temperature.
> I also replaced the oxidation column filling it with double dose of
> silvered cobalt oxide. It didn’t help. I also replaced magnesium
> perchlorate column. The measurements of the other samples (not filters)
> are good. If it is chlorine, what should I do with these filters?