170135_inorganicventures_flipping

10:5 Contamina(on from the Analyst and Apparatus

Contamina(on from the apparatus:

Table 10.1: Results of Spectrochemical Analysis (Hydrogen Fluoride, Hydrogen Chloride, and Nitric Acid [all high purity] analyzed aFer evaportaHon in Teflon, PlaHnum, and Quartz dishes)

Elements determined, ng/g A ND—not detected.

B TR = trace, not evaluated quanHtaHvely.

10:7 Contamina:on from the Analyst and Apparatus

Contamination from the apparatus: A Closer Look at Quartz

§ Opaque quartz has the highest trace element concentra4on and should not be used for trace analysis. § Transparent quartz (types I and II) are made from naturally occurring quartz crystals or sands. Type I is made by electric mel4ng and type II by flame mel4ng. Type II has slightly less impuri4es than type I (some impuri4es are vola4lized by the flame). § Type III quartz is made synthe4cally by vapor phase hydrolysis of pure silicon compounds such as SiCl4. This type of quartz is more pure than the natural quartz with the excep4on of Cl - which is ~ 50 ppm. § Type IV quartz is synthe4cally made from SiCl4 using a process involving electrical fusion of the oxidized staring material. It is as pure as type III, with respect to trace metal content, and contains much more Cl-. Use synthe4c quartz whenever possible.