I tried to identify plasma metabolites using the Agilent 6550 q-tof system. The spectral hits with the column are not coming as expected and seem similar to the blank run. please suggest some suitable columns with respective mobile phases to achieve optimum results. the column currently we have are the following-
Eclipse plus C18 RRHD 1.8um,2.1 X150mm
Poroshell 120 Bonus-RP 2.7 um 3.0X 100 mm
Zorbax sb-aq RRHD 1.8um,2.1 X100mm
PLEASE suggest.