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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Chapter 26, Problem 26.18QAP
Interpretation Introduction
(a)
Interpretation:
Average number of plates should be calculated.
Concept introduction:
Number of theoretical plates is given by following equation:
N = number of plates
tR = retention time
W = width of peak base
Average =
Interpretation Introduction
(b)
Interpretation:
Standard deviation for the N should be calculated.
Concept introduction:
Standard deviation will give how the values deviate from mean value of N.
Interpretation Introduction
(c)
Interpretation:
Average plate height of column should be calculated.
Concept introduction:
N = plate count
L = length of the packing (cm)
H = height of the column
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One method for quantitative determination of the concentration of constituents in a sample analyzed by gas chromatography is the area normalization method. In this method, complete elution of all of the sample constituents is necessary. The area of each peak is then measured and corrected for differences in detector response to the different eluates. This correction is accomplished by dividing the area by an empirically determined correction factor. The concentration of the analyte is found from the ratio of its corrected area to the total corrected area of all peaks. For a chromatogram containing three peaks, the relative areas were found to be 16.4, 45.2, and 30.2 in the order of increasing retention time. Calculate the percentage of each compound if the relative detector responses were 0.60, 0.78, and 0.88, respectively
One method for the quantitative determination of the concentration of constituents in a sample analyzed by gas chromatography is area normalization. Here, complete elution of all the sample constituents is necessary. The area of each peak is then measured and corrected for differences in detector response to the different eluates. This correction involves dividing the area by an empirically determined correction factor. The concentration of the analyte is found from the ratio of its corrected area to the total corrected area of all peaks. For a chromatogram containing three peaks, the relative areas were found to be 16.4, 45.2 and 30.2, in order of increasing retention time. Calculate the percentage of each compound if the relative detector responses were 0.60, 0.78 and 0.88, respectively.
4.Consider the peaks for pentafluorobenzene and benzene in the gas chromatogram shown here. The elution time for unretained solute is 1.06 min. The open tubular column is 30.0 m in length and 0.530 mm in diameter, with a layer of stationary phase 3.0 μm thick on the inner wall.
a) Measruing the width, w, at the baseline on the chromatogram, find the number of plates for these two compounds
b) Use your answer to (a) to find the resolution between the two peaks
c) Using the number of plates N=sqrtN1*N2 with the values from (a) calcuate what the resolution should be and compare your answer with the measured resolution in b
Chapter 26 Solutions
Principles of Instrumental Analysis
Ch. 26 - Prob. 26.1QAPCh. 26 - Prob. 26.2QAPCh. 26 - Prob. 26.3QAPCh. 26 - Prob. 26.4QAPCh. 26 - Prob. 26.5QAPCh. 26 - Prob. 26.6QAPCh. 26 - Prob. 26.7QAPCh. 26 - Prob. 26.8QAPCh. 26 - Prob. 26.9QAPCh. 26 - Prob. 26.10QAP
Ch. 26 - Prob. 26.11QAPCh. 26 - Prob. 26.12QAPCh. 26 - Prob. 26.13QAPCh. 26 - Prob. 26.14QAPCh. 26 - Prob. 26.15QAPCh. 26 - Prob. 26.16QAPCh. 26 - From the data in Problem 26-14, calculate for...Ch. 26 - Prob. 26.18QAPCh. 26 - Prob. 26.19QAPCh. 26 - Prob. 26.20QAPCh. 26 - Prob. 26.21QAPCh. 26 - Prob. 26.22QAPCh. 26 - Prob. 26.23QAP
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