How to take split ratio into account when calculating final desired concentration of internal standard or surrogate standard in method

I run a method that requires 30 ng of bromofluorobenzene (bfb) on column to meet the method's tune check spectral evaluation.  I have been preparing IS/SS secondary standards from stock standards according to calculations from a former operator of the system.  I notice the calculations do not include anything for split ratio.  I use an ATOMX purge and trap with the IS/SS prepared standard being autoinjected into the water sample.  Once the x uL of IS/SS mix is injected into x mL of sample, in order to achieve the desired ng of bfb on column, should I be dividing this number by the split ratio?  

Thank You.  

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  • I am asking because of the explanation in this application note from Agilent titled "Volatile Organic Compound Analysis Using Purge and Trap, Success with VOC Analysis Using the Agilent 5975C Mass Selective Detector".  I have never used split ratio when making the IS/SS standards but I just changed sample volumes so I have been reviewing procedures and came across this section of the app note where the split ratio is used in the calculation.  I believe this is referring to a direct injection but I don't understand how split ratio is used here.

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