A new method of inductively coupled plasma-triple quadruple mass spectrometry（ICP-MS/MS） was developed for the determination of 14 trace rare earth metal and 4 trace other metal impurities in cerium chelate with ultrahigh purity.01 g sample was digested by low pressure autoclaves with 1 mL HNO3 for 30 min at 120 ℃.Under the MS/MS detection mode

typical strong poly atomic and overlapping interferences on La

Pr

Gd

Tb and Dy from the matrix of Ce were fully eliminated（about 2-3 orders of improvement in comparison with conventional detection modes）

when the O2 and NH3 based dynamic reaction cell（DRC） technique was used and a low ratio of 0.3% for CeO+/Ce+ was accomplished by using the high matrix introduction（HMI） sample introduction system；Similarly

isotopic and poly atomic interferences on Ca and Fe from Ar under high matrix concentration levels were successfully eliminated by using the cool plasma detection mode plus the H2 and He based DRC technique.Under the optimized detection conditions

a RSD with long term stability was less than 5%（2 h

4.0 g/L）

the recoveries of 926%-108% and the detection limits（3s） of 0.001 2-0.071 5 μg/g for all of the analytes were obtained

indicating that the method could be applied in the rapid batch analysis of cerium chelate with 6N purity.