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Determination of protein concentration You want to determine the protein concentration in an unknown sample by use of the biuret method. The standard solutions needed were prepared by mixing the bovine serum albumin (BSA) stock solution, water, and the biuret reagent, as can be seen in the data table below. (The concentration of the BSA stock solution was 8.00 mg/mL). The solutions were left at room temperature for 30 minutes for the complete color development. The absorbance (at 540 nm) of each of the standard solutions was determined with a spectrophotometer using the first solution (with 0.000 mg/mL protein) as the blank (control), as shown below. test tube # | volume of BSA | volume of water | volume of biuret reagent | final protein conc. | Abs540 1 | 0.00 mL | 2.00 mL | 2.00 mL | 0.000 mg/mL | 0.00 2 | 0.20 mL | 1.80 mL | 2.00 mL | | 0.075 3 | 0.40 mL | 1.60 mL | 2.00 mL | | 0.162 4 | 0.60 mL | 1.40 mL | 2.00 mL | | 0.230 5 | 0.80 mL | 1.20 mL | 2.00 mL | | 0.333 6 | 1.00 mL | 1.00 mL | 2.00 mL | | 0.403 2.00 mL of the unknown sample in a cuvette was mixed with 2.00 mL of the biuret reagent. After 30 minutes, the absorbance of the unknown sample in the cuvette was measured to be 0.275. Your lab report should include the following: (1) Complete the data table shown above. (The calculations of the final protein concentrations should be shown below the table.) (2) Construct the standard curve using Excel (scatter plot needed), determine the trendline and obtain the equation for the line. (3) Calculate the concentration of the protein in the unknown sample (after mixing with the biuret reagent and before mixing with the biuret reagent). You need to show the calculations.

          Determination of protein concentration

You want to determine the protein concentration in an unknown sample by use of the biuret method. The standard solutions needed were prepared by mixing the bovine serum albumin (BSA) stock solution, water, and the biuret reagent, as can be seen in the data table below. (The concentration of the BSA stock solution was 8.00 mg/mL). The solutions were left at room temperature for 30 minutes for the complete color development. The absorbance (at 540 nm) of each of the standard solutions was determined with a spectrophotometer using the first solution (with 0.000 mg/mL protein) as the blank (control), as shown below.

test tube # | volume of BSA | volume of water | volume of biuret reagent | final protein conc. | Abs540
1 | 0.00 mL | 2.00 mL | 2.00 mL | 0.000 mg/mL | 0.00
2 | 0.20 mL | 1.80 mL | 2.00 mL | | 0.075
3 | 0.40 mL | 1.60 mL | 2.00 mL | | 0.162
4 | 0.60 mL | 1.40 mL | 2.00 mL | | 0.230
5 | 0.80 mL | 1.20 mL | 2.00 mL | | 0.333
6 | 1.00 mL | 1.00 mL | 2.00 mL | | 0.403

2.00 mL of the unknown sample in a cuvette was mixed with 2.00 mL of the biuret reagent. After 30 minutes, the absorbance of the unknown sample in the cuvette was measured to be 0.275. Your lab report should include the following:

(1) Complete the data table shown above. (The calculations of the final protein concentrations should be shown below the table.)

(2) Construct the standard curve using Excel (scatter plot needed), determine the trendline and obtain the equation for the line.

(3) Calculate the concentration of the protein in the unknown sample (after mixing with the biuret reagent and before mixing with the biuret reagent). You need to show the calculations.

Determination of protein concentration

You want to determine the protein concentration in an unknown sample by use of the biuret method. The standard solutions needed were prepared by mixing the bovine serum albumin (BSA) stock solution, water, and the biuret reagent, as can be seen in the data table below. (The concentration of the BSA stock solution was 8.00 mg/mL). The solutions were left at room temperature for 30 minutes for the complete color development. The absorbance (at 540 nm) of each of the standard solutions was determined with a spectrophotometer using the first solution (with 0.000 mg/mL protein) as the blank (control), as shown below.

test tube # | volume of BSA | volume of water | volume of biuret reagent | final protein conc. | Abs540
1 | 0.00 mL | 2.00 mL | 2.00 mL | 0.000 mg/mL | 0.00
2 | 0.20 mL | 1.80 mL | 2.00 mL | | 0.075
3 | 0.40 mL | 1.60 mL | 2.00 mL | | 0.162
4 | 0.60 mL | 1.40 mL | 2.00 mL | | 0.230
5 | 0.80 mL | 1.20 mL | 2.00 mL | | 0.333
6 | 1.00 mL | 1.00 mL | 2.00 mL | | 0.403

2.00 mL of the unknown sample in a cuvette was mixed with 2.00 mL of the biuret reagent. After 30 minutes, the absorbance of the unknown sample in the cuvette was measured to be 0.275. Your lab report should include the following:

(1) Complete the data table shown above. (The calculations of the final protein concentrations should be shown below the table.)

(2) Construct the standard curve using Excel (scatter plot needed), determine the trendline and obtain the equation for the line.

(3) Calculate the concentration of the protein in the unknown sample (after mixing with the biuret reagent and before mixing with the biuret reagent). You need to show the calculations.

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