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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