Biuret test was performed on a series of bovine serum albumin concentrations in

Question

Biuret test was performed on a series of bovine serum albumin concentrations in mg/ml. The standard curve (Optical density against concentration) was plotted using Excel program. Following equation is obtained. Y=0.3x-0.40 Calculate the concentration of an unknown protein sample in mu g/ml with an absorbance of 0.2 You will mix 2 liters of a 3M and 8 liters of 500 mM of Sodium Chloride. What is the concentration of mixed solution in M and mM. What is the concentration of a 36% glucose in nM (10 P) (mW: 180) 50 ml of a 0.4 M disodium phosphate solution is mixed with 80 ml of a 250 mM of monosodium phosphate solution. Calculate the pH of the buffer. Show your calculation Pk_a value of phosphoric acid = 7.2 (show your calculation)

Explanation / Answer

2. The given equation is:

y = 0.3x - 0.4

At absorbance, y=0.2

x = concentration in mg/ml

So, 0.2 = 0.3x - 0.4

0.2 + 0.4 =0.3x

x = 0.6/0.3 = 0.2 mg/ml = 0.2 * 1000 g/ml = 200 g/ml

3. We use the following equation,

C1V1 + C2V2 = C3V3

C1 = 3/2 M/L = 1.5 M/L

C2 = 500/8 mM/L = 500/8*1000 M/L = 0.0625 M/L

V1 = 2 L, V2 = 8 L, V3 = 10 L

So, 1.5 * 2 + 8 * 0.0625 = C3 *10

3 + 0.5 = 10C3

C3 = 3.5/10 = 0.35 M/L = 0.00035 mM/L

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