000 l volumetric flask and then diluted to 1000 ppm

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(5) Create a procedure and dilution for a 325 mg/tablet ASA to be placed in a 1.000 Lvolumetric flask and then diluted to 10.00 ppm in a 10.00 mL volumetric using a micropipette.1
Procedure – External Standards and a sample1.Make a stock solution (1.000L of 100 ppm acetylsalicylic acid in 2v/v% HCl). Make sure the acetylsalicylic acid is completely dissolved before you dilute to the mark. Invert the flask several times to ensure a homogenous solution (wet solid with methanol to increase solubility). 2.(1) Prepare 250 mL 2 v/v% HCl solution using a 10-mL graduated cylinder and a cleaned 250-mL plastic bottle (How do you make it?). (2) Prepare a series of calibration standards of different concentrations of acetylsalicylic acid (0, 4, 6, 8, 10, 15, 20 ppm). Use your 100 ppm stock solution plus the dilution function (C1V1=C2V2) to make the standards. You need only 10 mL total volume of each dilution. All dilutions will be made to contain 2 v/v% HCl, even your blank. 3.Each student will have ONE 10-mL volumetric flask. These are expensive measuringdevices, not storage bottles. Once each solution is prepared and inverted well, transfer the contents to a clean, labeled test tube. Clean the flask and re-use it.4.Look at the bottle of Aspirin tablets and record the amount of active ingredient (acetylsalicylic acid) printed on the label. Examine your dilutions table and design a procedure to dissolve and dilute your entire tablet in such a way that the final, theoretical concentration will be 10 ppm acetylsalicylic acid in 2 v/v% HCl. Transfer aportion of your diluted unknown into a clean, labeled test tube. Remember, all dilutions are to contain 2 v/v% HCl (Wet solid with methanol to increase solubility).Procedure – Standard Addition Method5.To a clean 10.00-mL volumetric flask, spike in the correct volume of 100.0 ppm acetylsalicylic acid standard stock solution so the knownspiked final concentration will be 10.00 ppm when you dilute to the mark (check your calculation before you make it!). 6.Add to this volumetric flask in 5, the same volume of the aspirin tablet solution (1L) that you used to prepare the unknown in step #4 above. Dilute to the mark with 2 v/v% HCl.

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