An Easy Guide for Practical Biochemistry Divya Shanthi D’sa, Sowbhagya Lakshmi
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1Laboratory Rules and Regulations2

Laboratory Hazards and First Aid1

Biochemical parameters aids in diagnosis and prognosis of diseases. The medical students should have the knowledge of the various tests, diagnostic investigations done in biochemistry laboratory. They should also be aware of all potential hazards and the safety measures.
The student is surrounded by many dangers (Fig. 1.1) such as:
  • Broken glassware.
  • Corrosive reagents.
  • Mechanical hazards.
  • Poisonous fumes that could be inhaled.
  • Inflammable chemicals.
  • Gas leakages.
  • Electrical hazards.
  • Lab coat has to be worn in order to protect oneself from corrosive splashes.
  • One has to be careful while handling gases.
  • Blood, urine, CSF and other biological fluids should be handled with great care as they are potential sources of infections like Hiv and Hepatitis.
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    Fig. 1.1: Signs of some Laboratory Hazards
  • Chemical work involving irritating chemicals and dangerous infectious materials should always be conducted under hoods with good exhaust and adequate ventilation.
  • Safety cabinets and hoods should be used while handling corrosive reagents.
  • Electrical heater and other electrical appliances should be checked and insulated frequently. Damage should be rectified immediately.
  • Bunsen burner should never be used around inflammable material like ether, and acetone.
  • General health should be maintained at all costs as an effective means for keeping natural immunity and resistance.
  • Eating and drinking in the laboratory must be avoided.
  • Exercise great care and take precautions while mouth pipetting. The mouth of the pipette should be plugged with cotton or piece of rubber while filling.
  • One should not be engaged in conversation or other disturbances.
  • Automatic dispensers and automatic pipettes must be used for pipetting acids, alkalis, corrosive solutions and poisonous solutions.
  • The hands should be kept free of cuts and abrasion.
  • Hands should be washed with soap water followed by washing with disinfectant material.
  • Pipettes and other instruments employed should be placed immediately in disinfectant solution.
  • Open flames should not be left unattended.
  • Any leakage of gas should be properly attended and reported.
  • Smoking should be strictly prohibited.
  • Burning match sticks should not be thrown in waste baskets.
  • Sand or blanket should be used to put off the small fire.
  • For longer blazes, “Fire Extinguishers” have to be used.
  • Water should NOT be used on electrical fire.
  • Water should NOT be used on a fire caused by organic solvents such as ether, alcohol, petrol, etc.
  • While trying to escape from fire, in case if it cannot be extinguished quickly, it is safe to stay close to the floor and crawl by covering mouth with damp cloth.
  1. If the corrosive solution swallowed is an acid:
    • Spit the corrosive solution.
    • Promptly rinse the mouth.
    • Antidotes such as 8% magnesium hydroxide (milk of magnesia) or egg white mixed in water can be used orally to neutralize the acid.
    • Seek medical help immediately.
  2. If the corrosive solution swallowed is an alkali:
    • Promptly rinse the mouth.
    • Antidotes such as lemon juice or 5% acetic acid can be taken orally to neutralize the alkali.
    • Seek medical help immediately.
Take the student to fresh air and seek medical help immediately.
From strong acids:
  • First wash with LOTS of water and then wash with 5% sodium carbonate or 5% ammonium hydroxide.
  • Seek medical help immediately.
From strong alkalies:
  • Wash immediately with LOTS of water and later with 5% boric acid or dilute acetic acid solution.
  • Seek medical help immediately.
Laboratory first aid refers to the immediate help given to an injured person. The first aid kit should contain:
  • Cotton wool and gauze
  • Roller bandage
  • Scissors
  • Acetic acid
  • Milk of magnesia
  • Spirit
  • Adhesive tapes
  • Disinfectant solution
  • 5% sodium carbonate.
  • All chemicals should be considered as potentially dangerous and should be handled carefully. One should be aware that accidental injuries can occur either from direct contact through skin, by inhaling vapors, powder or swallowing by mistake while pipetting.
  • Clear labeling of all the bottles containing chemicals and reagents should be done and their potential hazards should be noted on the label.
  • Reagent bottles should be held with both hands and should not be carried by holding their necks.
  • The reagent bottles in use should be kept on shelf at the eyelevel of the user.
  • Corrosive chemicals should be opened with great care and added slowly to water with continuous cooling and stirring as these substances can destroy the living tissue, e.g. Strong acids like sulfuric acid, hydrochloric acid and strong alkalies like potassium hydroxide, sodium hydroxide, etc.
  • Automatic dispensers should be used to dispense acids, alkalies and corrosive liquids.
  • Toxic chemicals such as cyanides, barbiturates must be kept locked in cupboards and mouth pipetting of these should be avoided at any cost.
  • Some organic solvents are highly toxic to certain organs, e.g. Benzene is toxic to bone marrow; carbon tetrachloride and halogenated hydrocarbons are toxic to liver, etc. Hence, their use should be minimized in assays.
  • Precautions must be taken while handling carcinogenic substances such as benzidine, orthotoulidine. Bottles containing such substances have to be labeled as CARCINOGENIC. Skin contact with them must be strictly avoided and rubber or plastic gloves should be used while handling these substances.
  • One has to be careful while handling explosive substances. Certain precautionary measures must be followed like:
    1. Perchloric acid should be kept in fume cupboard.
    2. Picric acid should be stored in a container of water tightly closed with cork or rubber stopper.
    3. Ether should be kept in brown or dark bottles away from sunlight since on exposure to sunlight they form peroxides, that when raised to certain sufficient concentration cause violent explosion.
    4. Cylinder containing inflammable gases like hydrogen, propane, acetylene should be kept outside the laboratory when not in use.
  • One should not be panic.
  • Alarm should be raised as soon as possible.
  • The laboratory should be evacuated, to minimize further damage to property.
  • Gas and electricity connections have to be turned off immediately.
  • In case of fire attacks, fire extinguishers should be used to tackle them.
  • In case of large fires, the fire brigade has to be called.
Chemical Waste
  • Neutralization of acids and alkalies should be done prior to their washing in the sink.
  • Organic solvents should be stored in metal drums and later it must be washed off.
  • Some chemicals can be cleared or disposed by INCINERATION.
Radioactive Waste
Expert opinion has to be taken for the disposal of radioactive waste, and their guidelines have to be strictly followed. Flushing radioactive substances down the sink can be very dangerous as they pollute the underground water table.