The influence of the helium flow rate, standard and collision mode on the detection limit of vanadium, chromium and arsenic in Cl-rich brines has been investigated. For the detection of vanadium, chromium and arsenic content in chloride matrix water by ICP-MS, the collision mode is preferable for the polyatomic interference correction. The optimal helium flow rate for this purpose is 2.5 ml/min. Under these conditions the detection limit of vanadium, chromium and arsenic decreases by order of two and is 10-5 mg/L.