Abstract:When inductively coupled plasma mass spectrometry (ICP-MS) is used to determine the Cu and Zn concentrations in geological samples, the measurement results are seriously disturbed, and the measured values deviate from the valid values, presumably because the relatively high geochemical abundance of Ti easily forms oxide particles (TiO) under high-temperature conditions. In this paper, an on-line correction method has developed by digestion of hydrofluoric acid-perchloric acid-nitric acid, reconstitution of aqua regia system treatment, and use of 103Rh as an internal standard to establish to eliminate the overlapping interference of Ti oxide. Experimental research of the effects of Ti on the isotopes 63Cu, 65Cu, and isotopes 64Zn, 66Zn, and the impact between TiO and Ni. The results illustrate that: (1) The overlap interference of Ti oxide to 65Cu is more severe than 63Cu, 64Zn is more rigorous than 66Zn, and the increase of interference value is not a simple positive correlation with the change of Ti concentration. (2) The ion count of 62TiO is similar to the 63Cu and 66Zn, and the interference increment value, which is helpful to correct the interference, is not related to the change in the concentration of the Ti element. (3) An ectopic interference to 62TiO is from the 62Ni. The interference value produced by 62TiO must be corrected for the contribution from the single element Ni. By on-line correction of the interference caused by TiO, it is more reasonable for ICP-MS to determine the isotopes of 63Cu and 66Zn, which significantly improves the accuracy and precision of Cu and Zn, reduces the detection limit and expands the linear range. The detection limit of 63Cu and 66Zn is 0.352μg/g and 0.628μg/g, respectively. The method accuracy is <5%, and the precision (RSD, n=7) is <5%. It is verified by the national level geochemical standard materials that the measured value is identical with the identified value.