Determination of metal impurity elements in high purity magnesium oxide powder by inductively coupled plasma tandem mass spectrometry

Abstract

The new analysis method of metal impurity elements in high purity magnesium oxide powder with good accuracy and reliability was established based on inductively coupled plasma tandem mass spectrometry (ICP-MS/MS). New mass filtering device was adopted in ICP-MS/MS to effectively reduce the polyatomic interference during determination of metal impurity elements in magnesium oxide matrix. Helium was used as collision gas, while O2 and NH3/He mixture was used as reaction gas. The elimination effect of interference was compared at single quadrupole (SQ) mode and tandem quadrupole (MS/MS) mode. It was found that some special MS interference could not be eliminated by helium collision mode, especially for the double charge ion interference. However, the conversion of analyte to oxide ion or cluster ion could realize the non-interference analysis of testing elements. Moreover, the detection limit was very low. The accuracy of method was evaluated by spiked recovery experiments. The results showed that the detection limit was 0.46-65.9 ng/L. The linear correlation coefficients (R2) of elements were not less than 0.999 8. The recoveries of actual samples were between 93% and 108%. The relative standard deviations (RSD) were between 1.6% and 4.4%. The proposed method could be applicable for the real-time monitoring of metal impurity elements in high purity magnesium oxide powder.