4. Solution to Chemistry Problem

1. A sample of biological material weighing m (mg) was hydrolyzed, solutions of cobalt chloride and ammonium buffer solution were added to the resulting protein hydrolysis and diluted to 50.00 ml. The polarographic wave of this solution is caused by the catalytic release of hydrogen at the cathode in the presence of the resulting complex compound of cobalt(II) with cystine contained in the protein hydrolysate. The height of the catalytic wave Id was measured at E = −1.6 V. 5.00 ml of a standard cystine solution [M((HOOCCH(NH2)CH2S)2 = 240.291 g/mol with a concentration of 2.00⋅10−5 mol/l] was added to the solution. The increase in the height of the catalytic wave at the same potential ΔId was 7.20 μA.
Calculate the concentration (mg/kg) of cystine in the following biological materials:
Option Biological material m, mg IdI μA
1 Wool 50.0 14.5