I have recently undertaken my first proteomics experiment (protein extraction from cells, 2DE, exicised spots, trypsin digestion, MALDI-TOF MS) but have not had much success and I was wondering if anyone could help me. I struggled to get any identifications because I seem to have quite a lot of artefactual peaks that appear across a number of samples. Although I used a laminar flow hood, wore gloves, a lab coat and covered my hair, I seem to have a number of contaminants. Some of them appear to be kertains and trypsin peaks, but I cannot identify the others. I was wondering if you had any suggestions as to what they might be? They are at m/z 1149, 1251, 1267, 1295, 1412, 1759 and 2186. They are towering above my keratin/trypsin peaks and peaks of interest. Also, does anyone know where I might be able to find a peak list of common contaminants (from keratins, trypsin, matrix etc.)?