Customfield to calculate Total betacaroteen


I need some help to create a customfield(s) to calculate Total betacaroteen,

The sample is measured with 2 wavelength(410nm,480nm), the formula is as follow:

(0.53xB)+(C410-B))x1667, where B=(C410-C480)/0.39

Use now excel to calculate:

Conc total Beta-caroteen bij 410 nm 0.94 mg/kg Amount 410 Conc voor Vit A act bij 480 nm 0.69 mg/kg Amount 480 B = 0.64 =(Amount410-Amount480)/.39 Pro vit A activity = 1064.7 IU/kg =((0.53*B)+(Amount410-B))*1667

If you need any further, please let me know

thank in advance

Wouter Boessenkool



  • Do you quantify the amounts in each wavelength using derived channels in your method set with the processing method linked to each wavelength/derived channel or does your instrument method perform a wavelength switch during acquisition?
  • We quantify the amounts in each wavelength using derived channels in your method set with the processing method linked to each wavelength/derived channel
  • Thanks. You should be able to do it with a few CFs, and you need to know the exact name of the 2 derived channels. Start with calculating B:  Peak, Real CF, search order Result Set Only. Make sure all your samples are labelled as U... example U1 U01 etc. Formula is ABS(U%.%.410nm(Amount)-U%.%.480nm(Amount)). Call this CF Beta_PartOne
    Next CF, again Peak, Real with Search Order Result Set Only, formula is:
    (0.53*Beta_PartOne)+(U%.%.410nm(Amount)-Beta_PartOne). Call this Beta_PartTwo
    A final Peak, CF of the formula 1667*Beta_PartTwo called Final_Amount. That should do it. You may have to put the channel names in inverted commas in the formula eg "410nm". And you have to process a sample set to generate a result set and the value should be in the result set. 
    This should work for each sample as the % in the formula will ask Empower to consider each sample and subsequent set of the different parts of the calculation as a stand alone sample. Ensure that the sample type and peak type are set to All in all the CFs. Good luck. 

  • Thanks very much for your info. I will start working on it in a couple off days.

    I let you know the results.

    Thanks again

  • I tested this on a project and it works fine for me. I'm not sure if you are looking for Area, Amount or Concentration of Betacaratone, that's not clear in your post. So for all these formulas, substitute the Area for whatever field you require and also be aware that the correct final answer will only populate in your second channel ie 480nm, since not all the arguments are present in the first channel. So if reporting on these results make sure to only report on the CORRECT channel ie 480nm.


    Peak, Real, Calculated Result Set Only All Sample and Peak Types:



    Peak, Real, Calculated Result Set Only All Sample and Peak Types:



    Peak, Real, Calculated Result Set Only All Sample and Peak Types:


    Hope this helps.

  • Thx. I will try it out today or tomorrow and will let you know.


  • I have made the following CF's:

    Formula 1, Beta_PartOne:

    ABS(U%.%.410nm(Amount)- U%.%.480nm(Amount))/0.39

    Formula 2,Beta_PartTwo:


    Formula 3, IU_kg:

    1667* Beta_PartTwo

    Field type: peak, Data type:real, search order result set, sample type: All, peak type: All.

    I called the last one Beta_IU_kg, easier for colleague to know what this means☺

    Sofar no results, what could be wrong? Wouter

  • Did you process a sample set to generate a result set, as per the search order Result Set Only? Do you definitely have the channel names right? Check the name of the derived channels in your method set and compare them to the ones in the custom field formula. Also, maybe send on a screenshot of how you run your standards. If you do bracketing with overlap it may not work as Amount should only come from the 1 calibration curve.

    Other things it may be include: Is the custom field in the project? Do you have the samples labelled as A... followed by something else eg A1, A2 etc?

  • I see now that we use data channels instead of derivated channels, is that a difference?

    And the names of the channels are: W2489 ChA and B.

    The samples are labeled as U.....

  • If you use data channels, maybe put the exact channel name in the formula, so W2489 ChA, make sure your spaces and capitals are exactly the same as the channel name. or else it wont be correct. Or you could make 2 new PDA derived channels under Single Wavelength, and call the 2 channels 410nm and 480nm, and as long as these names match in the formula, it should work. Hope this helps.
  • I have changed the ….nm into W2489 ChA or B and there is calculation per channel.There is no calculation between the channels, just only on the line of each channel(so I get negative results)

    ABS(U%.%.W2489 ChA(Amount)-U%.%.W2489 ChB(Amount))/0.39

    (0.53*Beta_PartOne)+(U%.%.W2489 ChA(Amount)-Beta_PartOne) 

    Maybe there is little bit of confusion about the derived channel from my side.

    I understand a derived channels as two separated channels measured by each there own wavelength.

  • The results are in the att. file
  • edited October 2020
    Your second CF is missing an ABS and a set of brackets. Change it to the below, and process again:

    (0.53*Beta_PartOne)+ABS((U%.%.W2489 ChA(Amount)-Beta_PartOne))

    As for channels, I got it to work by adding 2 derived channels, "Single Wavelength" to the method set, 410nm and 480nm. I called these 2 channels 410nm and 480nm and the first derived channel was 410nm, the second 480nm. Then i processed the sample set using this method set and it worked perfectly in the second channel, 480nm. But it doesnt matter what the channel is called, as long as you get the spelling exactly right.

    I think if you add the ABS, it will work. 
  • Your right, I have improved the formula:

    (0.53*Beta_PartOne)+ABS((U%.%.W2489 ChA(Amount)-Beta_PartOne))

    Processed a sample set again, now the results are only calculate per channel.

    Have att. results and a copy of the method set.

  • Maybe you can send me screenshot of your method set
  • Maybe you can send me screenshot of your method set
  • Thanks for sending the method set and your result. My method set was pretty much identical to yours, only its derived channels, not data channels. but that doesn't matter since you have the names right in your formula. I think the problem is your peak names.

    English is my primary language so I'm afraid I didn't fully understand your report method attached but if I'm reading it right, you call the peak name 2 different things per channel? So its called voor-pre-provit...etc in one channel (410nm) and its called beta-caratone in your second channel (480nm) is that correct? Why do you have 2 different names? my CFs will work only if the peak name is the same in both processing methods and channels. if you want to do it such that the formula is voor-pre-provit - betacaratone etc, then you need to edit the CFs.

    Is that what you are aiming for?

  • but you did understand. But it solved the problem. Super.

    I att. the results☺

  • That's great to hear. yes, I noticed the peak name was different in the 2 chromatograms in your previous report. I'm glad it seems to be working out for you now.
  • Oke. Maybe I can ask you about other CF's in near future?


  • Yes there are a lot of good users here so this is a great place to ask qs on CFs.

    Glad i could help.

  • Hi,

    here i'm again.

     I need some calculation for the following system:

    For a method we run for each sampleset a so called system suitibilaty:

    1e: we inject columnswitchtime solution: solution of 2 component and that twice.

    We have to calculate the duplicate difference for each component

    2e: we need the deviation of the intercept relative to third standard.

    I wil add the document we now use as example.

    Thanks in advance

  • Hello. When you say duplicate difference for each component what do you mean? Is it the difference in area between the first and second injection. Is the sample run twice on separate lines of the sample set or is it 2 injections? 
    And can you elaborate on deviation of the intercept?
    Maybe a screenshot of what the samples look like in the sample set would help. Thanks.
  • It's a difference in retentiontime of each component between those injection.

    I will send an example of the injection.

    Formula dev of intercept:B/(height or area) of the 3e standard*100%.

    Where B according: y=ax+b. In the formula in the fields you can choose for a B.

    Is the same B I guess?

    Did you see the system suitability document that add in the previous mail?

    Could you understand despite the language barrier.?

  • Thanks for your attachments. I understand the retention time calculation and its easy to do. Not sure about the deviation one yet. For the retention time calculation, you need to label your sample with the 2 injections as something like A or Sys or whatever suits you. Lets say Sys, then create a peak, real custom field, with search order Result Set Only and All Sample and Peak types. Your formula is:

    (ABS(Sys.1.(Retention Time)-Sys.2.(Retention Time))/((0.5*(Sys.1.(Retention Time)+Sys.2.(Retention Time))))*100

    Try that and it will give you the value you want but only report on the second injection since you need all the arguments present for the custom field to work properly and all arguments are only present in the second injection.

  • Edit: actually, a better way to do the above is with this formula below. I tested my first one and it gave me strange results, which I think is something to do with the ordering.  Change it to below and it will work, just make sure to add Summarize Custom Fields as the end of the sample set. You need this when using the AVE function. Done forget the correct number of periods (.) when entering the formula.

    (ABS(Sys.1.(Retention Time)-Sys.2.(Retention Time))/Sys.%..AVE(Retention Time))*100

  •  The formula works, the results on the second are indeed correct one. But there also results on the first report. Can they be hidden by another command?

    I have a question in general about the codes we use:
    in U%.%…. means U% all samples and .% per injection?
    Is always handy if I know where I talking about :)

    For the deviation your not sure about, means?

    Thanks Wouter

  • If you use the formula in my previous post with the AVE in it, you will get the correct results across both injections. I tested this and it worked fine for me, displaying the same result across both injections. If you want to exclude the first injection in the report, you could set up a Data Filtering Condition in the report method table where Sample Label = Sys1 and Injection =2. 
    If you need to exclude it as a stored result in the database, you can use Boolean conditions on either side of the equation. Try this, this should work:

    (EQ(Label,"Sys")&EQ(Injection,2))*(ABS(Sys.1.(Retention Time)-Sys.2.(Retention Time))/Sys.%..AVE(Retention Time))*100

    The above will only give the correct result on Injection 2 of the Sys sample and a 0.000 for every other result (ie a 0.000 is a fail since the only conditions where the CF will calculate is Injection 2 of Sys). Now, if you want to just have nothing, a blank field, for every other injection and sample then you need to add a counter-condition at the end of the CF and you also MUST have All or Nothing ticked for it to work. Be warned though, you dont want your CF formula too long, if its too long and complicated, sometimes the project crashes. Try this if thats what you need:

    (EQ(Label,"Sys")&EQ(Injection,2))*(ABS(Sys.1.(Retention Time)-Sys.2.(Retention Time))/Sys.%..AVE(Retention Time))*100+(NEQ(Label,"Sys")|NEQ(Injection,2))*-1*50000

    As for your codes, yes you are right, U% is any label of U or U1 or U11 or U111 or ULO78888! Basically anything of U or U followed by any combination of numbers or letters. Same for %- this will include ALL injections of a sample. whereas %.1.(Area) is only the 1st injection, %.3.(Area) is the 3rd injection etc. 

    I havent had a chance to look at your deviation problem, maybe i will try next week when i get access to some data. 

  •  I have used the last formula with at the end: -1*50000.

    The result is calculate right but the numbers are too small instead of 0.086 and 0.229

    I have now 0.00086 and 0.00229.

    So now I use this one:

    (EQ(Label,"Sys")&EQ(Injection,2))*(ABS(Sys.1.(Retention Time)-Sys.2.(Retention Time))/Sys.%..AVE(Retention Time))*100

    For the devation take your time:)

  • sorry this one:ABS(Sys.1.(Retention Time)-Sys.2.(Retention Time))/((0.5*(Sys.1.(Retention Time)+Sys.2.(Retention Time))))*100
Sign In or Register to comment.