Question

You have been tasked with preparing a serial dilution of ATP (507 g/mol) for a calcium assay. You will need 100 ul each of 108M, 10-PM, 10-M, 10-'M, 10-M, 10-'M. How do you prepare this agonist? Vi(107) = 100 ML (108) sorg/mol = 0.501 gime [Vi=10ML + 90 m H₂O 0. Sorg 1000ml VI(106) = (100+ 10) (107) IMLI IL TV, = 11 ML + 89 u2 H2O) Vi (10-5) -(100+ 11)(106) (Vi= 11.1 ML + 88.9 ML H₂O Vi(104)=(100+ 11.1) (10-5) [Vi= 11.11 ML + 88.89 ML H2O) Vi (10-3) -(100+ 11.11) (10-4) 6 points 1 Vi=11.111 ML + 88.889 M H2O)

Answer 1

You have to prepare the most concentrated one and then dilute each one by taking an aliquot of the inmediately more concentrated solution.

So, begin with the 10^-3 M . If you begin with the solid reagent, you can take 0.0507g of ATP and take them to 100mL:

1тol 1 1,000mL (0.0507g) ( )= 1*10-mol/L = 1* 10-3M L М 507g 100mL

The other dilutions can be obtained with 20 microliters of the inmediately more concentrated solution and taking them to 200 microliters, you will obtain a larger volume of each solution (180 microliters) but this helps us to round the volumes to integers. If you take 20 microliters of the 10^-3 M solution and then add solvent to get 200 microliters of solution you dilute 10x and obtain the 10^-4 M solution, this can be seen with the dilution equation:

M1 *Vi M2 V2 M2 M V/2

Zυμ = 1 * 10-4M M2 1 10M 200μL

Then, take 20 microliters of the 1*10^-4 M and add solvent to 200 microliters to obtain the 1*10^-5 M solution:

Zυμ = 1 * 10-5M M2 1 10M * 200μL

And so on:

Zυμ = 1 * 10-6M M2 1 105M 200μL

Zυμ = 1 * 107M M2 1* 10M 200μL

Zυμ M2 1* 107M* = 1 * 10-8M 200μL