Hello,
If you question is why the decrease in MS response? as a function of using the splitter,
this can be categorised into 2 parameters.
1) Makeup Gas Dilution : typically a column running from the injection port to a MS will have a flow
rate of 1ml/min, when using the splitter, there is makeup gas added to the splitter,
this can be usually from 3ml/min as set up by an Agilent Tech, you can use the Excel sheet
supplied by Forse, so calculate the actual extra volume of make up gas supplied.
WARNING!: You can measure this effect by dropping the Aux pressure, but not too much
as the system may try and draw gas into the MS from the FID.(save the method with a new test name)
2) Fix ratio : The splitter will always split to the MS and FID in the same ratio during a temperature
programme, so by changing the lengths, you can change the ratio.
WARNING!: If you shorten the MS column, without adjusting the Aux pressure, you will increase the
Makeup Gas dilution effect, and could actually lose response even though you altered the ratio.
Use the Excel sheet to test, p.s. you need to know the column Internal Diameters, as it may be
.1mm to MS and .18 to the FID.
kind regards
Alex