Mass Hunter unknown with NIST RI

Hello, Anyone can help me with Mass Hunter unknown using NIST20 RI?

I would like to use RI information in the NIST20 to assistant unknown analysis employ Mass Hunter unknown.

First, How can I choose the RI base on the column ? In NIST search program, there is an option to choose the retention index base on column polarity but I can not find from Mass Hunter unkown.

Second, The RI calculated using RT calibration tools with NIST20. The RI for  n-alkane is not hundred number (n-Heptane ,142-82-5,instead of 700, the calculated is 717)

Last. when select the RT match, it gives very few return. even the restriction is broader. The component RIs are different to the library RI ( the difference  are more the 10 in most case). 

It will be very appreciated if you give any suggestion.

Parents
  • Hi ,

    The only RI value MassHunter retrieves from NIST is the value for Semi-standard non-polar columns. There is currently not an option to use any other RI values. 

    As for creating the RT calibration file there are some good tips in this discussion that should help in making a usable calibration file.

    For your final issue, hopefully once you have a good calibration you will be able to tighten up your window and still get acceptable results.

    Let us know if you have any other questions or what you find after trying these suggestions.

  • Thanks Howard and ISH for your kindly reply. I do review all those information. But unfortunately, the Library method does not work for me.

    I do use  Semi-standard non-polar columns (DB5). and also tried the reference library created used   n-alkane RI standard only. There is still quite difference between the Library RI to the component RI.

    Any help is appreciated.

    (RTC use NIST20 Library)                                                                                (RTC use MS reference library)

    RT calibration use NIST 20 RT calibration use MS referene library
    Component RI Library RI RI Diff Component RI Library RI RI Diff
    710.6592202 734 -23.34077977 693.5951719 734 -40.4048
    710.6592202 734 -23.34077977 693.5951719 734 -40.4048
    767.7050355 763 4.705035512 751.2172076 763 -11.7828
    862.5235444 803 59.52354441 846.5235444 803 43.52354
    862.5235444 803 59.52354441 846.5235444 803 43.52354
    931.6318819 992 -60.36811813 915.7897797 992 -76.2102
    931.6318819 992 -60.36811813 915.7897797 992 -76.2102
    980.7488093 981 -0.251190654 965.4028377 981 -15.5972
    980.7488093 981 -0.251190654 965.4028377 981 -15.5972
    995.668836 984 11.66883601 980.4735717 984 -3.52643
    995.668836 984 11.66883601 980.4735717 984 -3.52643
    1007.868695 992 15.86869459 992.7966612 992 0.796661
    1007.868695 992 15.86869459 992.7966612 992 0.796661
    1027.946416 1018 9.946416255 1012.946416 1018 -5.05358
    1027.946416 1018 9.946416255 1012.946416 1018 -5.05358
  • Hello,

    Could anyone please help me with Mass Hunter  unknown analysis using NIST 20 Library RI information? Is the RI in NIST20 of any use in Mass Hunter unknown application?

    There are two kinds index in NIST20 for some compounds, ----- Retention Index and User index. what is  user index actually standing for?  Is there any user manual for NIST 20? Which index is actually used for RI (RT) matching?

    Any help would be much appreciated

Reply
  • Hello,

    Could anyone please help me with Mass Hunter  unknown analysis using NIST 20 Library RI information? Is the RI in NIST20 of any use in Mass Hunter unknown application?

    There are two kinds index in NIST20 for some compounds, ----- Retention Index and User index. what is  user index actually standing for?  Is there any user manual for NIST 20? Which index is actually used for RI (RT) matching?

    Any help would be much appreciated

Children
No Data
Was this helpful?