Cheapest SimDist software?..


I plan to attempt some SimDist analysis in accordance with D2887 on my agilent GC-FID.  I was hoping that I could achieve this without additional software (i.e. just through manual manipulation of the data acquired by Chemstation), but apparently this somehow isn't possible?

So, can anyone tell me what price-range I should expect for a third-party software in order to achieve this?

Thank you!

  • IIRC there might be an Agilent Simdist package that was intended to handle D2887. Haven't used that one. I mainly run D7169 hi temp now.

    I'm one of the real old simdist guys who started on the HP5880 back in 1980 when you were expected to program your own data handling routines if they were not conventional peak integration techniques covered by built-in ISTD & ESTD approaches. This was the first HP benchtop data system that was capable of slice integration and BASIC program development. So you had to write your own programs.

    At the time D2887 was a proposed ASTM method and the only simdist they had. I highly recommend getting a vintage copy of the D2887-80 method to build the familiarity needed to go forward with 21st century efforts. Since this was written when you were expected to program yourself. For the next couple decades the integrators would handle slice integration and Basic programming, but as PC's became powerful enough and things like Chemstation took over from integrators, slices are not an option any more.

    Simdist is based on area slices (not peak integration) of each sample calibrated against RT's of peaks in a known standard of n-hydrocarbons.

    The modern equivalent of slices is the raw digital curve data in the form of a .CDF file, which needs to be exported from the Chemstation, then processed afterward by the type of software package you might be aware of.

    To experiment you might try a demo version from Envantage (vendor we are using at CGI), or Separation Systems, both of which are leaders active on the ASTM subcommittee that handles simdist.

    We are still on Envantage Simdist2000 for routine work but I am validating their newest Dragon Simdist2 and getting excellent agreement using the same calibration data and CDF files. Dragon is a bit more complicated so you might try to start with Simdist2000 yourself if it is still available, but it is only supposed to be proven up to Windows 7.

    I don't actually know the prices since our main office handles that, but you could get started on a demo version as a free trial.

    Definitely follow the latest version of D2887 since there is a world of difference after all these decades.

  • Thank you very much for taking the time to give such a detailed response!  

    I have one question... can you recommend a software package (or packages) that would allow me to slice the CDF file as you describe?

    I would still like to attempt to do this myself manually, without the use of 3rd party software. I actually attempted to produce and validate some of my own data today (via analysis of the D2887 reference gas oil and quantitative calibration standard, i.e. an n-alkane STD).

    I did this by analyzing the standards and several hydrocarbon mixtures (diesel, gasoline, JetA1, etc.), then integrating the data in chemstation and copying the integration data to excel.  From there I simply determined a cumulative running total of peak integrations, determined the elution time at key points (i.e. when 10%, 20%, 30%, etc, of the mixture had eluted - based on cumulative peak integration), and from there converted the elution time to a boiling point based on the analysis of the n-alkane D2887 standard and the polynomial line of best fit which I determined (relating elution time and b pt).

    As you pointed out, this process utilizes peak integration though, NOT continuous integral slicing.  I was surprised how good the resultant data was regardless, I was almost within spec of the D2887 ASTM according to my RGO analysis (only one or two data-points were slightly too far off from the required spec).  I think this approach would more than suffice for rough analysis (given that peak integration of this kind of data is almost continuous across the elution axis), BUT obviously not in accordance to ASTM..  One other issue I found was having to subjectively determine what is the IBP and FBP (i.e. the 0% and 100% points).

    At this point I should clearly just pay for the software... but I don't have the funds immediately available and to be honest, prefer the challenge/learning experience of attempting to solve the problem myself.

    Thank you again!

  • You are going to need the netCDF manipulation apps from Unidata. The core functions are downloadable without cost such as the decompression & dumping EXE or DLL. I first learned how to dump CDF to a text file, then pay close attention to the header which is only one page, followed by many pages of raw data. These sections can be dumped separately. CDF is an extensible file type and should be studied in detail.

    This is what I used in the 2000's to extract the raw slices from the type of CDF's that would otherwise be input to Simdist software.

    I dumped the slices into the first column of Excel and went from there. Blank baseline file for subtraction into another column. Corrected signal for processing in the next column. Visual Basic to process, and use other rows & columns as the database for reference hydrocarbon RT's BP's and calculated results. You can chart the corrected slices to get a chromatogram from Excel.

    This would be a good time to join ASTM which is not very costly for individual membership. You are also welcome to attend a committee meeting in person even if you are not a member. Petroleum Committee D2 is meeting in Denver this time toward the end of June. Travel & Hotel can be costly but if you join the subcommittee for Simdist you will get the minutes of the meeting even if you do not attend.

    Hope to see you there!

  • Thank you!  Can you recommend a utility gui or cli that I can use to actually view or convert my CDF files?  The unidata website contains lots of dead links to supposed solutions, and I've also tried using R and Rstudio, but I've been completely unable to either view or convert my CDF files.

    It's been very frustrating and I've found no help online...

    Any suggestions you have would be greatly apprecieated!  Thank you.

  • Hello, finding an available utility to handle netCDF is quite a tedious task that I have tried myself for the past few months. If you are only working with Agilent Chemstation, I would suggest exporting the chromatogram to CSV instead of AIA. That can be done from File --> Export File --> CSV File --> Select Signal, specify location. From there you can just import the CSV to Excel and let VBA work out the calculation you need.


  • You may like NetCDF Ninja, fairly new version 2 available.

    V2 installs and runs on Windows 11.

    To graph the signal (chromatogram); Load All Data > selection window shows only (*.nc) file type, use dropdown to choose All Files (*.*) instead > browse to your desired .CDF file to Open > file loads as indicated in message window > select item: Variables > select variable: ordinate_values > click button: Plot Variable

    To capture numerical data, Export Text button > choose your own target folder named as desired, to autocreate ordinate_values.txt in that target folder.

    Import ordinate_values.txt to Excel using the Excel text input wizard.


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