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ERT 207 ANALYTICAL CHEMISTRY
SEM I (2011/2012)
Tutorial Chromatography
TUTORIAL : SPECTROSCOPY
NAME
MATRIC
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Question 1
In a protein sample, amines (RNH2) react with picric acid to form amine picrates, which absorb
strongly at 395 nm (є = 1.25 x 104). An unknown amine (0.1155 g) is dissolved in water and
diluted to 100 ml. A 1 ml aliquot of this is diluted to 250 ml for measurement.
(i)
(ii)
Interpret the color absorption and color observed of the protein sample at the 395 nm.
If this final solution exhibits an absorbance of 0.454 at 395 nm using a 1.00-cm cell,
calculate the formula weight of the amine.
Question 2
A 50 ml protein sample fraction recovered from a column chromatography was analyzed for
protein content using the Lowry method. The following data are the means of a duplicate
analysis using Bovine Serum Albumin (BSA) as a standard:
Figure Q1: Graph of protein analysis using Bovine Serum Albumin (BSA).
(i)
(ii)
Based on the graph in Figure Q1, interpret the color absorption and color observed of the
protein sample at the measured wavelength.
If a 1 ml of the protein sample has an absorbance of 1.50, calculate protein concentration
(mg/ml) and total protein quantity of this sample fraction.