Could the autodilution be kicking in? Typically it is set at 20,000 or
30,000 mV, but if that was changed or if the box was checked, then that
could give rise to what you see.
On 9/6/2019 11:07 PM, Pousali Pathak wrote:
> Dear all,
> We performed carbon and oxygen isotope measurements in carbonate and
> water samples respectively in our gas bench attached to MAT-253 IRMS
> where we found splitted sample peaks. Ref CO2 is giving 1300 mV
> intensity with proper shapes. However for a time event method of 6
> sample peaks, the first sample peak is giving around 6000mV intensity
> and the rest 5 sample peaks are giving 200-400 mV intensities
> subsequently. Moreover all the sample peaks are appearing in splitted
> form or in two phases. This pattern is consistent through out the
> analysis for all samples and blanks (flushed with He+CO2). We kept CO2
> pressure of 3 bar and He pressure of 0.9 bar during the analysis.
> Please suggest me about what could be the problem here.