sentence: A salt gradient was applied in steps of 0 , 10 , 15 , 20 , 25 , 30 , 35 , 40 , 45 , 50 , 57 , 64 , 90 and 700 mM ammonium acetate in 5 % ACN , 0.1 % formic acid and the resultant peptides loaded directly into the sample loop of a 0.18 × 100 mm BioBasic C18 RP LC column of a ProteomeX workstation ( Thermo Electron ) .