HP Lab Midterms

• Hazards and handling of common chemicals

  • Acetic Acid
  • Acetone
  • Ammonium hydroxide
  • Aniline
  • Chloroform
  • Chromic acid
  • Diaminobenzidine
  • Dioxane
  • Dyes
  • Ethanol
  • Ether
  • Ethylene glycol ethers
  • Formaldehyde
  • Formic acid
  • Gluteraldehyde
  • Hydrochloric acid (Hcl)
  • Hydroquinones
  • Iodine
  • Isopentane
  • Mercuric chloride
  • Methanol
  • Nitric Acid
  • Phenol
  • Picric Acid
  • POTASSIUM PERMANGANATE
  • SODIUM AZIDE
  • SILVER SALTS
  • SODIUM HYPOCHLORITE
  • SULFURIC ACID
  • ZINC CHLORIDE
• Acetic Acid


  • Do not mix with (glacial) acetic acid with chromic acid and nitric acid
  • Irritant and corrosive
  • Fixative and dehydrating agent
• Acetone


  • Flammable, Volatile and a narcotic drug in high concentration
  • Is regulated by PDEA (needs permit)
• Ammonium hydroxide


  • Irritant
  • Used to make ammonia water (bluing agent in staining)
  • Store away from acid
  • Don't mix with formaldehyde
• Aniline


  • Clearing agent
  • Irritant, Sensitizer, Toxic, and Carcinogenic
• Chloroform


  • Clearing agent
  • Toxic and Carcinogenic
  • Do not burn and Do not evaporate
• Chromic acid


  • Toxic, Corrosive, Carcinogenic, and Oxidizer
  • ENVIRONMENTAL HAZARD
• Diaminobenzidine


  • Used as reagent for immunohistochemistry
  • Carcinogenic
  • Do not mix with chlorine bleach
• Dioxane


  • Dehydrating agent
  • Irritant, flammable
  • Has an explosive property
• Dyes


  • Dangerous in powder state, liquid state pose little risk
• Ethanol


  • Common dehydrating agent. Also a fixative
  • Irritant and flamable
• Ether


  • Irritant
  • Mostly target nervous system
  • Has an explosive property (explosive peroxides)
• Ethylene glycol ethers


  • Toxic and Combustible liquid
• Formaldehyde


  • Skin and eye irritant
  • Most serious hazard for lab workers
  • Toxic, Carcinogenic, and Corrosive
  • Exposure during grossing is the greatest risk in a well ventilated lab
• Formic acid


  • Decalcifying agent
  • Irritant and Corrosive
• Gluteraldehyde

  • Fixative
  • Skin and eye Irritant
• Hydrochloric acid (Hcl)


  • Decalcifying agent
  • Irritant
• Hydroquinones


  • Irritant
• Iodine


  • Used in staining
  • Irritant, corrosive and sensitizer
• Isopentane


  • Irritant, flammable, and volatile
  • Fixative
• Mercuric chloride


  • Irritant and corrosive
  • SEVERE ENVIRONMENTAL HAZARD
• Methanol

  • Irritant and Flammable
  • May cause blindness
• Nitric Acid


  • Toxic and corrosive
  • most common clearing agent
  • combustible
• Phenol


  • Fixative
• Picric Acid


  • Explosive when dry or when combined with metal/metallic salts
  • Should not be disposed in sinks, may form explosive picrates with metal pipes
  • Jars and cap threads should be wpied with damp towel to avoid drying
• POTASSIUM PERMANGANATE


  • Irritant
  • Strong oxidant, should not be mixed with acetic acid, ammonium hydroxide, ethanol, ethylene glycol, glycerol, hydrochloric acid, hydrogen peroxide or sulfuric acid
• SODIUM AZIDE


  • Toxic
  • It explode when placed in contact with metals and should not be discarded down the drain
• SILVER SALTS


  • Safe when used as fresh solutions, but can be explosive when solutions become old
  • Serious environmental hazard
• SODIUM HYPOCHLORITE


  • Strong oxidant
  • Eye irritant
  • Corrosive to most metals
  • Do not mix with bleach with formaldehyde or diaminobenzidine (DAB)
• SULFURIC ACID


  • Strong irritant to the skin, eyes and respiratory system
  • Corrosive to metals
  • Concentrated acid produces fumes that are dangerous to health
• ZINC CHLORIDE


  • Skin and eye irritant
  • Can cause severe GI problems if ingested
  • Corrosive to most metals, including stainless steel
  • Should not be used in tissue processor
• Main factors involved in fixation

  • Hydrogen ion concentration
  • Temperature
  • Thickness of the section
  • Osmolality
  • Concentration
  • Duration of fixation
  • Speed
  • Penetration
  • Volume
• Types of fixatives


  • Simple Fixatives
  • Compound Fixatives
  • Microanatomical Fixatives
  • Cytological Fixatives
• Simple Fixatives


  • Aldehydes
  • Metallic Fixatives
  • Picric acid
  • Acetic acid
  • Acetone
  • Alcohol
  • Osmium tetroxide
• Compound Fixatives


  • 10% BBZZ For Heiden
  • 10% buffered neutral formalin
  • 10% formol saline
  • Bouin's solution
  • Brasil solution
  • Zenker's solution Zenker-formal (kelly's solution)
  • Formol sublimate (formol corrosive)
  • Heidenhain's Susa
• Nuclear Fixatives


  • Flemming's Fluid
  • Carnoy's Fluid
  • Bouin's Fluid
  • Newcomer's Fluid
  • Heidenhain's Susa
• Cytoplasmic Fixatives


  • Flemming's fluid without acetic acid
  • Kelly's fluid
  • Formalin with "post-chroming"
  • Regards fluid (Muller fluid)
  • Orth's Fluid
• Histochemical Fixatives


  • Formol saline 10%
  • Absolute ethyl alcohol
  • Newcomer's fluid
  • Acetone
• Formaldehyde (Formalin)


  • 10% Formol-Saline
  • 10% Neutral buffered formalin or phosphate –Buffered formalin
  • Formol-Corrosive (Formol Sublimate)
  • Alcoholic Formalin (Gendre's) Fixative
• Glutaraldehyde Fixative


  • Made up of two formaldehyde residues, linked by three carbon chains
  • Fixation time varies from half hour to two hours