Cloud-point extraction.Traces of lead in drinking water came adverse health effects. The micelle-forming surfactant Triton X-114 (plus the co-surfactant cetyl trimethylammonium bromide) and a crown ether ligand extract and preconcentrate Ph for analysis by inductively coupled plasma-optical emission spectrometry. The hydrophobic metal complex is extracted into the hydrophobic interior of micelles formed by Triton X-114 (Figure 28-17). Surfactants and crown ether are added to 245 ml. of acidified aqueous sample. After 30 min for extraction, the solution is heated and becomes cloudy as the micelles aggregate into a separate phase containing essentially all Pb(II). The aqueous phase is then removed. The micellar phase is back-extracted with 5.0 ml of aqueous citrate solution that complexes Pb(II) more tightly than the surfactants. All Pb(II) ends up in the aqueous phase. By what factor is Pb(II) preconcentrated in this procedure? preconcentration factor: Drinking water with negligible lead content was fortified with 2.14 μg Pb(IIL. Triplicate measurements yielded a mean of 1.93 pg Pb(II/L and a standard deviation of 0.2 pg Pb(II). Find the percent recovery of the spike. percent recovery: Determine the 95% confidence interval for the spike recovery. Refer to the table of Student's t values as needed. % 95% confidence interval:+ PP/L Does the spike recovery differ from the expected value of 2.14 pg/L. Pb2+ at the 95% confidence level? ○ yes O no Determine the 95% confidence interval for the spike recovery if results were the same for six measurements instead of three. Refer to the table of Student's r values as needed. 95% confidence interval: If results were the same for six measurements instead of three, does the spike recovery differ from the expected value at the 95% confidence level? yes no
Cloud-point extraction.Traces of lead in drinking water came adverse health effects. The micelle-forming surfactant Triton X-114 (plus the co-surfactant cetyl trimethylammonium bromide) and a crown ether ligand extract and preconcentrate Ph for analysis by inductively coupled plasma-optical emission spectrometry. The hydrophobic metal complex is extracted into the hydrophobic interior of micelles formed by Triton X-114 (Figure 28-17). Surfactants and crown ether are added to 245 ml. of acidified aqueous sample. After 30 min for extraction, the solution is heated and becomes cloudy as the micelles aggregate into a separate phase containing essentially all Pb(II). The aqueous phase is then removed. The micellar phase is back-extracted with 5.0 ml of aqueous citrate solution that complexes Pb(II) more tightly than the surfactants. All Pb(II) ends up in the aqueous phase. By what factor is Pb(II) preconcentrated in this procedure? preconcentration factor: Drinking water with negligible lead content was fortified with 2.14 μg Pb(IIL. Triplicate measurements yielded a mean of 1.93 pg Pb(II/L and a standard deviation of 0.2 pg Pb(II). Find the percent recovery of the spike. percent recovery: Determine the 95% confidence interval for the spike recovery. Refer to the table of Student's t values as needed. % 95% confidence interval:+ PP/L Does the spike recovery differ from the expected value of 2.14 pg/L. Pb2+ at the 95% confidence level? ○ yes O no Determine the 95% confidence interval for the spike recovery if results were the same for six measurements instead of three. Refer to the table of Student's r values as needed. 95% confidence interval: If results were the same for six measurements instead of three, does the spike recovery differ from the expected value at the 95% confidence level? yes no
Principles of Instrumental Analysis
7th Edition
ISBN:9781305577213
Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher:Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Chapter7: Components Of Optical Instruments
Section: Chapter Questions
Problem 7.15QAP
Related questions
Question
None
Transcribed Image Text:Cloud-point extraction.Traces of lead in drinking water came adverse health effects. The micelle-forming surfactant
Triton X-114 (plus the co-surfactant cetyl trimethylammonium bromide) and a crown ether ligand extract and
preconcentrate Ph for analysis by inductively coupled plasma-optical emission spectrometry. The hydrophobic metal
complex is extracted into the hydrophobic interior of micelles formed by Triton X-114 (Figure 28-17).
Surfactants and crown ether are added to 245 ml. of acidified aqueous sample. After 30 min for extraction, the solution is
heated and becomes cloudy as the micelles aggregate into a separate phase containing essentially all Pb(II). The aqueous
phase is then removed. The micellar phase is back-extracted with 5.0 ml of aqueous citrate solution that complexes
Pb(II) more tightly than the surfactants. All Pb(II) ends up in the aqueous phase. By what factor is Pb(II) preconcentrated
in this procedure?
preconcentration factor:
Drinking water with negligible lead content was fortified with 2.14 μg Pb(IIL. Triplicate measurements yielded a mean
of 1.93 pg Pb(II/L and a standard deviation of 0.2 pg Pb(II). Find the percent recovery of the spike.
percent recovery:
Determine the 95% confidence interval for the spike recovery. Refer to the table of Student's t values as needed.
%
95% confidence interval:+
PP/L
Does the spike recovery differ from the expected value of 2.14 pg/L. Pb2+ at the 95% confidence level?
○ yes
O no
Determine the 95% confidence interval for the spike recovery if results were the same for six measurements instead of
three. Refer to the table of Student's r values as needed.
95% confidence interval:
If results were the same for six measurements instead of three, does the spike recovery differ from the expected value at
the 95% confidence level?
yes
no
Expert Solution
This question has been solved!
Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.
Step by step
Solved in 2 steps with 7 images
Recommended textbooks for you
Principles of Instrumental Analysis
Chemistry
ISBN:
9781305577213
Author:
Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher:
Cengage Learning
Principles of Instrumental Analysis
Chemistry
ISBN:
9781305577213
Author:
Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher:
Cengage Learning