Accurate Determination of Ti in Zircon by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry

The Ti content in zircon M257 was determined in-situ by LA-ICP-MS using Si and Zr as internal standards and NIST 610, GSE-1G, BHVO-2G, BCR-2G, ATHO-G, KL2-G and T1-G as external standards. The large difference between measured and referred values by using BCR-2G, ATHO-G, KL2-G and T1-G as external standards and Si or Zr as internal standard indicated that the four NIST standard materials were not suitable for external materials. Whether using Si as internal and BHVO-2G as external standards, or Zr as internal and NIST 610 as external standards, the difference between measured and referred values was less than 4%, which means that the two standard materials can be used as external standards selectively. Using GSE-1G as the external standard, whether Zr or Si is used as the internal standard, the difference between measured and referred values is less than 3%, which indicates that GSE-1G is a better external standard material. The Ti contents in 5 zircon standards were measured by using Si as internal and GSE-1G as external standards. The Ti distributions were heterogeneous in 91500 and homogeneous in GJ-1, M257, PENGLAI and MUDTANK. However, the Ti contents in the zircon standards of GJ-1, M257, PENGLAI and MUDTANK were less than 5 μg/g. Therefore all 5 zircon standards can not be used as external materials because of heterogeneity or lower Ti content, which can only be used as quality control materials in determination of Ti in zircons, except for 91500.