Nitric acid AsO, SbO, and TiO respectively. Some precious metals, such as pure gold and platinum-group metals do not react with nitric acid, though pure gold does react with "aqua regia", a mixture of concentrated nitric acid and hydrochloric acid. However, some less noble metals (Ag, Cu, ...) present in some gold alloys relatively poor in gold such as colored gold can be easily oxidized and dissolved by nitric acid, leading to colour changes of the gold-alloy surface. Nitric acid is used as a cheap means in jewelry shops to quickly spot low-gold alloys (< 14 carats) and to rapidly assess the
Fulvic acid only method that the California departments of agriculture will accept when registering a product. California does not recognize fulvic acid as separate substance from humic acid and requires that all label registrations list the content as humic acid only. Until 2017, Oregon also required using this method but has recently switched to the Lamar Method of fulvic acid quantification and now allows the label registration of fulvic acid as a substance apart from humic acid. The Verploegh and Brandvold method (V&B) quantifies both humic and fulvic acid and is a quick, cost effective, and easy test to perform. It does