ICP-AES Determination of 13 Metal Elements in High-Purity Tungsten Hexafluoride

ICP-AES was applied to the determination of Cr,Mn,Fe,Co,Ni,Cu,Zn,Mg,Ca,Na,K,Pb and Mo in high purity tungsten hexafluoride (WF6). To prevent the reaction of WF6 with moisture in air,a closed pipeline system for taking the sample was designed. Sample of the liquid WF6 was sucked into the transparent PTFE sample receptor from the sample container until the liquid surface reached to a definite height,from which the sample mass was estimated. The inlet value was closed and the outlet of the sample receptor was opened to let the WF6 vapor to leave the receptor and enter into the absorption bottle and finally high purity helium was passed through the sample receptor to drive WF6 completely into the absorption bottle. The exact sample mass was calculated from the difference of masses of the absorption bottle before and after the absorption of WF6. The metal elements remained in the sample receptor,after the driving of WF6,were dissolved in dil. aqueous ammonia,dil. HNO3 and dil. HF,and the solution was diluted to 100 mL,which was used for ICP-AES determination. Values of detection limit (3s) for the 13 elements mentioned above were all less than 0.005 mg·L-1. Tests for recovery and precision were made,giving values of recovery in the range of 90.5% to 104.2%,and RSD′s (n=11) in the range of 3.2% to 7.8%.