I am trying to quantify my data to make graphs, hope you can help

I have a sealed 385mL bottle filled with 375mL wine. So I have 10mL left for air, of this 10mL how do I work out how much oxygen I have (just within this 10mL space)? Or alternatively, is it just 10mL or 10mg?

I am thinking i need to calculate the surface area and times by the % oxygen present in the atmosphere?

Or perhaps times density by 10? However, the density of air is 1.29kg/m

^{3} so i would need to put my 10mL into kg?

But i am really not certain.

Thanks!