<prompt> For biochemical analysis vitreous in sent in -Hydrochloric acidPhenolFormalinFluoride  <response>: 10 mg fluoride in every 1 ml of vitreous humor is added for preservation in analysis of alcohol, cocaine, cyanide and CO. Dr. Narayana Reddys Synopsis of Forensic Medicine Toxicology 27 th edition pg. 62. 