Problem with normalization and - proteomics analysis (LC-MS)

Hi folks,

I am working with proteomics data, containing mainly LC-MS and NMRI analysis. Firstly, I must normalise data to give valuable compound for biostatistics analysis such as data imputation. I have never had to deal with such data. Can you advise me on which method to choose (I usually work in Matlab, I do not know if it is a good idea) - as far as I am concerned, using average area or median area (Z-scores as normalisation factor) will be the best idea for my data. However, I was wondering if I am not making a big mistake here because of distribution of my data (qqplot in the attachment).

I would be grateful for any advice - I'm just a layman in biostatistics.