Nitric acid concentrated acid and nitric oxide for dilute acid. or Concentrated nitric acid oxidizes I, P, and S into HIO, HPO, and HSO, respectively. Nitric acid reacts with proteins to form yellow nitrated products. This reaction is known as the xanthoproteic reaction. This test is carried out by adding concentrated nitric acid to the substance being tested, and then heating the mixture. If proteins that contain amino acids with aromatic rings are present, the mixture turns yellow. Upon adding a base such as ammonia, the color turns orange. These color changes are caused by nitrated aromatic rings in the protein. Xanthoproteic
Acid perfusion test Acid perfusion test Acid perfusion test, also called the Bernstein test, is a test done to reproduce the pain when the lower esophagus is irrigated with an acid solution in people with GERD (gastroesophageal reflux disease). There will be a negative result in normal people, but a false positive reading may be seen in up to 15% of people. Bernstein test is obsolete nowadays. 24 hour pH monitoring is the gold standard for GERD. However, the initial management is with proton pump inhibitors. If the patient does not respond to it, and continues to have symptoms of GERD, i.e. heartburn,