Thanks Jim for the info.

I'm worried someone may have added a new working standard long ago and may have input some values wrong. It converns me as well as we have two very similar working standards who are set up in very similar ways but have some values altered (delta value 0 vs. -0.971) yet have the same primary standard ratio.



On Mon, 8 Jun 2020 16:18:00 -0700, Jim Palandri <[log in to unmask]> wrote:

>Our ancient Isodat 2.5 standard editor came from the factory with a
>number of similar items already present. Perhaps for calibration
>purposes there. Hesitant to delete them, they have been ignored since
>day one.
>
>Added here and used on a regular basis of course are our own monitoring,
>or, "reference" gases, O2, CO2, CO, and H2. All are given meaningful
>names long enough so as not to be confused with others already present.
>
>-Jim
>
>On 6/8/2020 10:22 AM, Peter R wrote:
>> Hello peeps!
>>
>> I've been browsing around Isodat trying to figure some things out. I came across the Standard Editor and have a few questions.
>> Who decides the "Value".  For example, one of our "working standards" is "Lab N2 tank". The gas is "N2", Delta is "d15N/14N" and Value is "-0.971". Where did this number come from?
>>
>> That same working standard uses the "Air-N2" Primary standard whose "Prim. Std. Ratio" is "0.0036782". Should this number be "0.0036764" which is the R15N/14N of Air?
>>
>> Other working standards have similar configurations but have a different value for N2 such that the "d15N/14N" is 0 vs Air-N2, but the primary standard ratio is the same as the "Lab N2 Tank" working standard.
>>
>> Any information about this tab would be great since the Isodat manual lacks a little bit.
>>
>> Thanks,
>> Peter
>>
>
>--
>Jim Palandri
>Research Associate
>Department of Earth Sciences
>1272 University of Oregon
>Eugene, OR 97403-1272