Hi I am doing this amperometry lab and I am a little confused on number 6. I pos

Question

Hi I am doing this amperometry lab and I am a little confused on number 6. I posted the procedure so you can see. I am not sure on how to calculate the analyte solution after stock solution is added. or even what the analyte solution would be. any info would help thanks.

2. To a 15 mL beaker add a small stir bar and 10 mL of phosphate-buffered saline (PBS) solution. This will be the electrolyte solution. 3. Construct an electrochemical cell: Immerse the glassy carbon electrode, a platinum wire electrode, and a Ag wire electrode coated with AgCl in the PBS solution. No electrodes should touch one another. The solution should be stirred throughout the electrochemical analysis 4. The background current resulting from the PBS solution will now be measured: a. Setup>Technique: configure the software for Amperometric i-t curve b. Setup -> Parameters: apply a potential of-0.15 V, sample interval: 0.1 s, Run time: 2100 s, Quiet time: 0 s, Sensitivity: 1E-004 AN Scales during run: 3 5. At the 600 s time point the first aliquot of 50 mM stock potassium ferricyanide solution should be added to the cell. Each subsequent aliquot should be added every 60 s: a. 50 uL stock solution, wait 60 s b. 100 L stock solution, wait 60 s C. 150 L stock solution, wait 60 s d. 200 L stock solution, wait 60 s e, 250 L stock solution, wait 60 s f. 150 HL stock solution unknown concentration 6. Calculate the concentration of the analyte solution after each addition of stock solution

Explanation / Answer

I'm not quite sure but I think that the 10 mL of electrolyte solution is the analyte solution right?. If it's not please tell which it is.

Now to get the new concentration all you have to do is apply dillution factor. All of these solutions are made with dillutions, so, all you need is the final volume (innitial volume + aliquot volume), and then apply the following expression:

C = Ci * (aliquot volume/final volume) Where Ci is the innitial concentration of the analyte.

You already have the aliquot volume of the stock solution, and the final volume you may get it by suming the innitial volume (in part a is 10 mL) with the aliquot volume (in this case 50 uL). For part b) the aliquot volume will be 100 uL but the final volume will be the final volume of part a, plus the aliquot volume of this part. In other words something like 10 mL + 100 + 50 will be the final volume, and continue to do so, with the other parts (Be sure to use the correct units). Now, in this case, let's convert the 10 mL to uL:

10 mL * 1000 uL/1mL = 10000 uL
So the final volume in part a) will be 10050 uL, in part B) 10050+100 = 10150 uL, and so on.

Hope this helps

Related Questions

Navigate

• Browse (All)
• Browse H
• Subjects

---