Ravi,

What packing are you using for the NA1500?  If you were told you could
run 200 samples per packing it sounds as if you are using the NCS
packing which would be a waste if you're looking for NC analysis.

William Anderson mentions the size of the O2 loop in relation to sample
size.  He's right that running the relatively low combustible material
in your samples will oxidize the copper very quickly and this will
reduce the number of samples per packing.  If you can tell me the number
of coils in the loop I can tell you it's size.  Small loops are
available from CE Instruments.

Cheers

Peter

Ravi Bhushan wrote:
>
> Dear Friends,
>
> We have a FISONS NA1500 NC analyser. We are using it frequently for the
> analyses of marine sediments for carbon and nitrogen content. Fisons
> principals claim that one can run upto ~200 samples per column filling but
> the best I have been able to run is not more than 120 samples averaging
> ~100 samples per filling, which is on a very lower side realising the
> cost of each filling. Can anyone suggest some alternative. Also if anyone
> can provide me the following information :
>
> 1) We are maintaining sample size of ~10mg, but it sometimes becomes
> difficult for samples with very low carbon and nitrogen content. Does the
> sample size controls the no of runs per filling.
>
> 2) Are there any standards available for analyses of marine sediments with
> different concs. of carbon and nitrogen content.
>
> 3) Does the acidified samples (samples treated by HCl for removal of
> carbonate fraction, HCl fumed filters etc) has any effect on the life of
> the column filling. We have found while using acid treated samples that
> column gets consumed very fast, sometimes just after 25-30 runs. Any
> solution for this problem.
>
> I shall be grateful if someone could give me feedback on this.
>
> Thanking you in anticipation
>
> Regards
>
> Ravi
>
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