Hydrogen (99.995% purity) was used as a reducing gas with argon (99.998% purity) as the purge gas and drag. The sample was previously degassed at 323 K for 1 h in an argon flow. The analysis was ...

A simpler method for determining gold purity in jewelry is the “touchstone” testing process ... touchstone and observe. The acid has dissolved both the 10k and 14k samples. The unknown metal is ...