Quantitative Analysis Project: Determine Your Amino Acid



Quantitative Analysis Project: Determine Your Amino Acid

Goal: You want to determine an unknown amino acid that you found in the biology laboratory. However, before you can determine the unknown amino acid you must come up with a procedure of how to determine it. A good lab procedure will come from knowledge of your previous labs.

What you will include in a final report:

• Your "unknown amino acid" name, weight, polarity, and some information on the importance of your amino acid biologically

• A full lab procedure that you and your partner used to determine the amino acid.

• All the calculations for sample preparation

• All calculation to determine amino acid molecular weights.

• Appropriate pKas for your unknown amino acid

• A titration curve

• Show the ionization reactions

• Show all forms of the amino acids at each phase in the titration curve.

• Calculate the isoelectric point.

Your final lab report should include a short introduction about your amino acid, and the concept of a titration curve. It should also include sample prep section, results/calculations and discussion.

Added to the lab report, please include your lab procedure on a separate page(s). Remember the lab procedure must contain all pertinent information so that any chemist or science student could perform the procedure without using other references.

The knowledge and laboratory items you have available to you

• Unknown amino acid that needs to have a solubility of around 0.04g/mL or greater

- Think about how much sample you have before you make the easiest dilution. You will need enough for two titrations.

• 0.1M HCl (you will make this and standardize it against your 0.1M NaOH)

-As partners you only need to make 500 or 1000mL together)

• 0.1M NaOH (you have made this and standardized this)

• Burette

• Beakers (several)

• Stir bar

• Magnetic stir plate

• pH meter (should be calibrated)

• Clamp

Things to think about:

• The amino acids are MOST LIKELY in their neutral state, at what pH will the solution of amino acid begin?

• How will you apply both the 0.1MHCL and 0.1M NaOH to the titration curve?

- Think about how acid or base could affect your amino acid

• How can you determine the molecular weight of the amino acid from a titration curve?

• Does adding water to your initial amino acid solution change the pH?

• How many titratable protons are there?

References:

• Think back to Biochemistry class if you have had that.

• Refer to your Quant textbook

• The internet has lots of helpful tips on amino acids and different types of lab procedures which includes Tables of pKa’s, MW and solubilities….

If you have questions, Please ASK!

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