You will have to ask Agilent.  MOSH and MOAH are components of mineral oil.

http://www.agilent.com/en-us/newsletters/accessagilent/2017/jan/moshmoah?cid=13624

Rather than buying and setting up your own equipment, you might be better off to send samples to a 3rd party contract lab that is appropriately equipped.

There is a difference between a method and an analytical technique. GC-FID is an analytical technique; if you sent me your sample for mineral oil analysis I would most likely use GC-FID as a part of my method. However, there is more to a method than just the instrument. You have to properly obtain and prepare your sample for instrumental analysis, and you have not given us any information about how you did that.

It sounds as if you are not an analytical chemist or a chromatographer. Your question sounds like you have plenty of equipment and little analytical expertise.

A quick look at typical compositions of these ointments:  might reveal the fact that they are a mixture of materials of very different characteristics and molecular sizes.

Chromatographers would also shy away from GC because the volatility range of the .desired component (mineral oil) is large, and the odds of a good separation for quantitation are low.  A GPC separation with ri detection and a small pore size column set might work pretty well, since the other components are much smaller molecules. 

There are many 'ways to skin a cat' but that is probably the first way I'd consider, providing I had the tools to use. 

you can use FTIR analytical method for  determination of mineral oil .find it on below link

http://pubs.acs.org/doi/pdf/10.1021/jf00059a002

Samarth,

An analysis for mineral oil in an ointment is not the same as an analysis of mineral oil off a leaf. A successful, accurate analysis take the sample matrix into consideration. This suggestion does not.

Dear Scot Abbott

if  I don't having any standard reference method for analysis of particular matrix,I refer other possible methods , with the validation of that method i use if for my purpose.

i am trying  to show other possible methods.

thank you for your comment.

 An internet search for analysis for mineral oils in cosmetics brought up several pages of 'hits', among them:    http://www.bfr.bund.de/cm/343/mineral-oils-depicted-by-gas-chromatograms-principals-for-the-analysis-in-food.pdf . Sliide 44 shows chromatograms in several cosmetics.