you can use XPSpeak fit software which is freely available. 

 yes，my results root in this software. But its better to use the software supported by instrument manufacturer. Different XPS instruments make different results.

You have perhaps one of these two problems ...

* When you cannot get the same ratio of O/C from an integration of peak area in the raw data and the peak fitting results on that same raw data, your peak fitting results are sloppy (wrong).

* When you cannot get the same ratio of O/C in a survey scan and high resolution scans, your sensitive factors and/or data scales are incorrect in one or the other settings.

First of all, I must say that when you are fitting graphene (or nanotubes or graphite) you must carrefully select the shape of your C-C/C=C/C-H peak. If you took simple combination of Lorrentzian/Gaussian shape, you did a mistake. For conductive phase of carbon you you need to use other functions (е.g. Doniach-Sunjic), because you will have a "tale" at higher BE. When you not take it into the account, you overestimate the "oxidized" carbon, look to the CASAXPS manual book. You dont have to use the CASA software but you will know what the shape of the peak should be.

Secondly. it is always difficult to correlate the amount of oxygen derived from C1s fit and from the atomic composition, becuase :

a) C1s and O1s electrons are escaping from different depths

b) You cannot separate C-O-C and C-OH peaks and therefore you have uncertainty if for one C-O carbon you should count 1 oxygen or 1/2 oxygen. Same for COOC and COOH

Please see the book attached via link below

http://www.casaxps.com/help_manual/manual_updates/peak_fitting_in_xps.pdf

If you have rGO then you will typically have a conducing sample, so the sp2 carbon should typically be fitted with an asymmetric line shape.  A good starting point for this is to use a line shape derived from HOPG.

For your quantification you must also ensure you are using the correct sensitivity factors for your instrument and that transmission function correction is applied.  Whilst XPSPeakFit is nice software, I am always sceptical abouts its accuracy - in tests I have performed on well characterised samples, I have much more flexibility and certainty in more well supported software such as  CasaXPS or Thermo's Avantage

The main problem in fitting rGO ist the problem with contaminations from adventitious carbon and adsorpt oxygen/water.

Basically you might check about your sample preparation.

Second thing is: How is your count rate? If your sample shows low count rate, much information gets lost.

Basically you can try to measure one fresh sample besides one older sample (both produced under the same conditions to identify the contaminants.

Dear Alexander Sasinska, your advice about contaminations is important for XPS measurement, especially for my GO sample. I will improve my experiment process to decrease the contamination effect. Thanks a lot !

Dear David J. Morgan, i have considered the asymmetric line shape, and the using of  C1s peak from standard sample when i fit C1s peak, but i don't konw how to complete this fitting process. As you said " to use a line shape derived from HOPG ", how should i handle this?

Dear Anton Manakhov, i will read the book first, and check my peak fitting again. After that, i may bother you again if i can't solve my problem very well.Thanks for your help !

 Dear Anton Manakhov, can you tell me  the reason  why couldn't i separate C-O-C and C-OH peaks? I am really confused. Looking forward to your reply !