Here is a potentially elementary question about stable C isotope
analysis...please bear with me as I am a beginner at isotope analysis.

I want to analyse some samples of sea water for DOC isotopic
composition.I collected my samples from a remote location last summer. I
was admittedly under-prepared to preserve the samples in the field, and
after some frantic research, I was told by one source that the best thing
I could do under the circumstances was to filter the water through
pre-combusted Whatmann glass filters, and store the water in glass bottles
in a cold(<4C), dark location. I did this, and my samples have been
sitting in
this state since September.

My question is: Is it still possible to analyse these samples or should I
discard them?
Thank you for your help

L. Mulkins