Principles of Instrumental Analysis
7th Edition
ISBN: 9781305577213
Author: Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher: Cengage Learning
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Question
Chapter 9, Problem 9.20QAP
Interpretation Introduction
Interpretation:
Precipitate protein is obtained by treating 5.00 mL sample of blood with trichloroacetic acid. The final solution has pH of 3 and this solution is extracted with two portions of 5 ml of methyl isobutyl
Concept introduction:
Beer Lambert law gives the relationship between absorbance and concentration of a sample. For the calculation of concentration, the following the equation of straight line as follows:
Where,
y = absorbance
x = concentration of sample
m is slope of graph plotted between absorbance and concentration of the sample.
And,
C is intercept of the graph.
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A 5.00-mL sample of blood was treated with trichloroacetic acid to precipitate proteins. After centrifugation, the resulting solution was brought to pH 3 and extracted with two 5-mL portions of methyl isobutyl ketone containing the lead-complexing agent APCD. The extract was aspirated directly into an air/acetylene flame and yielded an absorbance of 0.569 at 283.3 nm. Five-milliliter aliquots of standard solutions containing 0.400 and 0.600 ppm of lead were treated in the same way and yielded absorbances of 0.396 and 0.599. Please calculate the concentration of lead in the sample in ppm.
A 5.00-mL sample of blood was treated with trichloroacetic acid to precipitate proteins. After centrifugation, the resulting solution was brought to pH 3 and extracted with two 5-mL portions of methyl isobutyl ketone containing the lead-complexing agent APCD. The extract was aspirated directly into an air/acetylene flame and yielded an absorbance of 0.527 at 283.3 nm. Five-milliliter aliquots of standard solutions containing 0.400 and 0.600 ppm of lead were treated in the same way and yielded absorbances of 0.396 and 0.599. Find the concentration of lead in the sample in ppm assuming that Beer’s law is followed.
20 tablets containing the dibasic drug ethambutol hydrochloride (MW 277.2 g/mol) were powdered. 0.3354 g of tablet powder was dissolved in 10 mL of 2 M sodium hydroxide and was extracted with 5 x 25 mL quantities of chloroform. The combined extracts were evaporated and the residue was dissolved in 100 mL of anhydrous acetic acid. Non-aqueous titration was carried out using 1-naphtholbenzein solution as indicator and 0.1014 M acetous perchloric acid.
Volume of acetous perchloric acid required = 14.2 mL, weight of 20 tablets = 3.367 g, state
content of ethambutol hydrochloride per tablet = 100 mg.
Calculate the % of stated content in the tablets.
Chapter 9 Solutions
Principles of Instrumental Analysis
Ch. 9 - Prob. 9.1QAPCh. 9 - Prob. 9.2QAPCh. 9 - Why is an electrothermal atomizer more sensitive...Ch. 9 - Prob. 9.4QAPCh. 9 - Prob. 9.5QAPCh. 9 - Prob. 9.6QAPCh. 9 - Prob. 9.7QAPCh. 9 - Prob. 9.8QAPCh. 9 - Prob. 9.9QAPCh. 9 - Prob. 9.10QAP
Ch. 9 - Prob. 9.11QAPCh. 9 - Prob. 9.12QAPCh. 9 - Prob. 9.13QAPCh. 9 - Prob. 9.14QAPCh. 9 - Prob. 9.15QAPCh. 9 - Prob. 9.16QAPCh. 9 - Prob. 9.17QAPCh. 9 - In the concentration range of 1 to 100 g/mL P,...Ch. 9 - Prob. 9.19QAPCh. 9 - Prob. 9.20QAPCh. 9 - Prob. 9.21QAPCh. 9 - The chromium in an aqueous sample was determined...Ch. 9 - Prob. 9.23QAP
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