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 15, Problem 15.8QAP
Interpretation Introduction
(a)
Interpretation:
A working curve from the data should be constructed.
Concept introduction:
Standard addition method is used to analyze complex samples which matrix effect is significant. One common approach is standard addition technique is spiking of sample. In this method, one or more increments of a standard solution is added to the several aliquots of sample containing same volume. Each solution is then diluted to a fixed volume and experiment is proceeded.
Interpretation Introduction
(b)
Interpretation:
A linear least-squares equation for the data should be determined.
Concept introduction:
The slope of the line,
The intercept,
Interpretation Introduction
(c)
Interpretation:
The standard deviation of the slope and intercept and the standard deviation about regression for the curve should be determined.
Concept introduction:
Standard deviation about regression,
N − number of points used.
The standard deviation of the slope,
The standard deviation of the intercept,
Interpretation Introduction
(d)
Interpretation:
The concentration of Zn2+ in the sample should be calculated.
Concept introduction:
Standard addition method is used to analyze complex samples which matrix effect is significant. One common approach is standard addition technique is spiking of sample. In this method, one or more increments of a standard solution is added to the several aliquots of sample containing same volume. Each solution is then diluted to a fixed volume and experiment is proceeded.
Interpretation Introduction
(e)
Interpretation:
The standard deviation for the result in part (d) should be calculated.
Concept introduction:
Standard deviation of the results obtained from standard addition method =
M − number of replicates
N- number of calibration points.
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A student wanted to determine the level of lead in amoxicillin powder, so he
transferred 148 mg of the powder to 200 ml volumetric flask and completed
the volume volumetrically, then he transferred 5 ml of the obtained solution to
50 ml volumetric flask and completed the volume properly, and read the
absorbance of the obtained solution on AAS. The reading was 0.48. and the
calibration equation was: "Y =12.25 x- 0.05" (concentration microg./mL).
?"Calculate the content of lead in amoxicillin as "ppm
326.5.a O
605.0 .b O
60.5.c O
17.5.d O
584.7.e O
أخل اختياري
A student wanted to
determine the level of lead in
amoxicillin powder, so he
transferred 148 mg of the
powder to 200 ml volumetric
flask and completed the
volume volumetrically, then
he transferred 5 ml of the
obtained solution to 50 ml
volumetric flask and
completed the volume
properly, and read the
absorbance of the obtained
solution on AAS. The reading
was 0.48. and the calibration
equation was: "Y =12.25 x-
0.05" (concentration
microg./mL). Calculate the
content of lead in amoxicillin
as "ppm"?
O a. 326.5
O b. 605.0
Exactly 5.00 mL aliquots of a
solution containing analyte X were
transferred into 50.00-mL
volumetric flasks and the pH of
the solution is adjusted to 9.0. The
following volumes of a standard
solution containing 2.00 µg/mL of
X were then added into each flask
and the mixture was diluted to
volume: 0.000, 0.500, 1.00, 1.50
and 2.00 mL. The fluorescence of
each of these solutions was
measured with a fluorometer, and
the following values were
obtained: 3.26, 4.80, 6.42, 8.02
and 9.56, respectively.
ii. Using relevant functions in
Excel, derive a
least-squares equation for
the data, and use the
parameters of this
equation to find the
concentration of the
phenobarbital in the
unknown solution.
Chapter 15 Solutions
Principles of Instrumental Analysis
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