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Good Laboratory Practices (GLP)
:: Laboratory Tips

Laboratory Tips for Students

  1. Organic Lab is the one lab where water can be the death of a reaction. Many students make the mistake of beginning each lab by washing their glassware. Soon, they find out, too much time has been wasted, their glassware is wet and they have no way to dry it. Clean your glassware at the end of a lab period so that it has time to dry for the next lab period. In case washing with water is inevitable, dry it with the help of acetone.
  2. Always label reagents and flask contents. Many organic liquids are clear and colorless just like water, so are many aqueous solutions such as acids and bases. 
  3. Liquid organic reagents are best measured by volume. Most common organic liquids have their densities reported in one or more of the reference books (Mass/volume=density).
  4. Speaking of liquids - Some fabrics (nylons, rayon etc.) dissolve when in contact with solvents such as acetone, ethyl acetate. Sulfuric acid (same acid used in car batteries) will leave holes in cotton clothing, even in dilute form. Don't wear your best clothes to lab and always use lab coats.
  5. Some excellent sources for physical data on common organic chemicals encountered in the undergraduate laboratory (boiling point, melting point and density) are:
    1) The CRC Handbook of Chemistry and Physics
    2) Aldrich Chemical Company Catalog
    3) The Merck Index
  6. Cooling water always enters the bottom of the condenser and flows out the top at a gentle pace, no need to blow off hoses and soak you lab mates. Check to see if the water is running before heating starts.
  7. Check the glass surface for its temperature before disassembling distillation and reflux equipment.
  8. Many organcs don't mix or dissolve in water and thus require special waste containers. Do not pour organics down the sink.
  9. When performing extraction or separation, SAVE BOTH LAYERS (organic and water) until you are sure which contains the desired product. Can't remember which layer is which? Add a few drops of water to both from your wash bottle, the rest will be obvious.
  10. Always stop distillation well before the boiling flask goes dry.
  11. Residues concentrated to dryness or near dryness during distillation may be unstable and explode. (This is particularly important with ethers and some alcohols which can form organic peroxides).
  12. Use enough grease on glass joints to prevent "freezing" (but not so much that it drips from the joints) except for Teflon stopcocks, which are never greased. Glass joints which come in contact with "Strong Bases" (KOH, NaOH etc.) need to be essentially greased. Failure to clean them promptly after use will result in permanent sealing of the glass surfaces.
  13. Never leave a reaction unattended. If you need to leave the lab for a few min. (restroom break, etc.) ask one of your classmates or the instructor to watch your reaction.

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