B Odour Mixing Protocol - michelletytong/TRGProtocols GitHub Wiki

Written by Arish Mudra Rakshasa (Sept 2017) Earlham College, Richmond, IN, USA

Preparation

Wear clean gloves and a lab coat, and leave all personal items outside the lab. Gather the following materials:

  • Clean vials and caps (as many as there are odours to be mixed).
  • P20, P200, and P1000 micropipettes.
  • P20, P200, and P1000 micropipette filter tips.
  • Clean 100 mL graduated cylinder.
  • Mineral oil (open new and label with date, if needed).
  • Required odourants (found in the flammables cabinet in SH 161).
  • Mixture amount reference sheet (Talk to Michelle Tong)
  • Typical odourants: (+)-limonene (Cat no: 183164 Sigma-Aldrich) and (-)-limonene (Cat no: 218367 Sigma-Aldrich)

Procedure

Mineral oil

  1. Transfer 50 mL of mineral oil into a graduated cylinder. Precautions: mineral oil is viscous, so pour along the sides of the cylinder to avoid air bubbles. Pour slowly to avoid overshooting, because it takes a little bit for it to settle. Observe the lower meniscus at eye level to get an accurate measurement.

  2. Label a clean vial “MO” along with your initials and the date using tape.

  3. Transfer the 50 mL mineral oil into this vial.

Precautions: again, due to viscosity of the oil, pour it slowly and along the sides of the vial, to avoid air bubbles. Try to transfer as much of it as possible.

Odourant

  1. Transfer 50 mL of mineral oil into a graduated cylinder.

  2. Label a clean vial with the name of the odourant, your initials, and the date.

  3. Transfer the 50 mL mineral oil into this vial.

  4. Find the appropriate amount of odourant to create a solution of approximately 1 Pa vapour pressure (ref. Odour_Dilutions_TONG.xls). For (+)/(-)limonene, this is 102 µL.

Precautions: only use filter tips to transfer odourants!

  1. Using the appropriate micropipette, transfer this amount of odourant into the vial of mineral oil. For limonene, you would use a P200 set to 102 µL.

Precautions: feel free to immerse your pipette tip into the mineral oil to get all the odourant out. Do not tilt your pipette too much.

  1. Secure the cap on the vial and invert the vial several times to thoroughly mix the odourant with the mineral oil. Set the prepared vials in a tray or box. Avoid carrying them in your hands.

Fresh odours have to be mixed every day an experiment is performed. Odours from the previous day cannot be reused!

Clean-Up

  1. Clean all glassware in the sinks and leave them to dry.
  2. Make sure that there are enough pipette tips, clean vials, and chemicals for the next time someone needs to mix odours.
  3. Wipe down the workspace with alcohol.

Odour Dilutions