ESI-MS problems/questions

Hi there!

I started recently to use a microTOF II-HB to analyze some solutions. I never used this instrument before and I have some problems/questions.

1. When I run ACN to obtain a blank there is a strong peak at 931.440 m/z (10^5), is there something wrong with the instrument? Shuld I clean the components?

2. I get the gist of the tuning the source parameters but i'm not sure how actually these will affect my results. Can someone give me a link/name to a good source to understand better how to build my method?

3. I know I could use ChemDraw to predict the peaks of my analyte, but given that it's a solution I'm not sure how to predict the various coordination structures

Any help would be great! Thanks