課程名稱︰分析化學一
課程性質︰必修
課程教師︰張煥宗
開課學院：理學院
開課系所︰化學系
考試日期（年月日）︰2009.12.07
考試時限（分鐘）：10:10am~12:40pm
是否需發放獎勵金：是~Danke
（如未明確表示，則不予發放）
試題 :
I. Distinguish the differences between each pair (60pts,4pts each)
1. calibration check and quality control samples
2. intra-assay precision and intermediate precision
3. detection limit and sensitivity
4. confidence level and confidence interval
5. variance and standard deviation
6. linear range and dynamic range
7. F test and Q test
8. z and t (both in Statistics)
9. accuracy and precision
10. systematic error and random error
11. auxiliary complexing agent and masking agent
12. indirect titration and back titration
13. method blank and reagent blank
14. standard solution and blank solution
15. false positive and false negative
II. Short question (52pts,4pts each)
1. How can sulfide ion in aqueous solution be determined?
2. How can the hardness of water be determineed?
3. How can Mg2+ be determined in the presence of Al3+?
4. How does solution pH affect the stability of FeY2-?
5. Why is it important to use a right size of micropipet to transfer
liquid solution?
6. Calculate the concentration of NaCl that was prepared by dissolving
2.620(±0.002)g in 100.00(±0.004)mL.
7. How can you ensure a new approach is useful for practical use?
8. Why does student's t increase upon increasing confidence level?
9. How does standard deviation affect the Gaussian distribution if the
numbers of measurements are the same?
10. Explain the equation:
Sx=(Sy/|m|)*{(1/k+1/n+[(y-yave)^2/(m^2)*Σ(xi-xave)^2]}^(1/2)
11. Suggest a method to decide whether a questionable value is retained
or rejected.
12. Suggest a method to decide whether a pipet shall be calibrated.
13. Is anything wrong on this statement: The spike recovery is 100% if the
concentration of spiked analyte is 100nM after adding 95nM standard
analyte to sample containing 5nM analyte.
III. EDTA (52pts)
1. Write down the structure of EDTA. (4pts)
2. Besides titration, give one example of the application of EDTA. (4pts)
3. What is the molar ration of EDTA and metal ions when forming
complexes? (4pts)
4. Arrange the stability of MYn-4 of the following metal ions:
Na+, Mg2+, Fe2+ and Fe3+. (4pts)
5. Arrange the stability of FeY- in solution separately containing 0.01M
NH3, 0.1M NH3, 0.1M ATP, and 0.2M ATP. (4pts)
6. Define chelate effect. (4pts)
7. Consider the titration of 100.0mL of 1.0mM Zn2+ with 2.0mM EDTA in a buffer
at pH 10.0 containing 0.5M NH3. (Kf for ZnY2- = 10^16.50)
(A) Calculate αY4- at pH 10.00 (pK1 0.0, pK2 1.5, pK3 2.00, pK4 2.69
pK5 6.13,and pK6 10.37). (4pts)
(B) Calculate αZn2+ in 0.5M NH3 (logβ1 2.18, logβ2 4.43, logβ3 6.74
and logβ4 8.70) (Neglect NH4+) (4pts)
(C) Calculate the conditonal formation constant for ZnY2-. (4pts)
(D) Find pZn2+ after addition of 20, 50,and 60mL EDTA. (12pts, 4pts each)
(E) If ATP instead of NH3 is used, which titration curve has a sharper
break? (4pts)
IV. Statistics: (40pts, 4pts each)
(Answer the questions based on 95% confidence level)
(A)
ν: 4 5 6 7 8 9 10 15 25 30 40
t(95%): 2.78 2.57 2.45 2.36 2.31 2.26 2.23 2.13 2.06 2.04 2.02
F at 95% ν1= 3 4 5 6
ν2=3 9.28 9.12 9.01 8.94
4 6.59 6.39 6.26 6.16
5 5.41 5.19 5.05 4.95
6 4.76 4.53 4.39 4.28
Data for the concentration (mM) of NO measured by two different method are:
Analyst A: 2.502, 2.507, 2.505, 2.499, 2.509, and 2.508
Analyst B: 2.468, 2.496, 2.490, 2.488, and 2.478
1. Calculate the mean and standard deviation of NO from Analyst A.
2. Calculate the confidence interval of the concentration of NO from Analyst A
3. Calculate the confidence interval if Analyst A conducted 32 measurements?
4. If the true value is 2.510, is the result from Analyst A acceptable?
5. If the true value is 2.510, is the result from Analyst B acceptable?
6. Are the standard deviations of Analyst A and B different based on F-test?
7. Are the results from Analyst A and B different based on t test?
8. The intensity (I) of the chemiluminescence of NO reacting with O3 is
expressed as KC+D, where Kis 2.2±0.2, C is the concentration (μM) of
NO, and D is (1±0.1)*10^-4. Calculate the concentration of NO at
I = (6.0±0.3)*10^-3.
9. If you develop a new approach for the dectetion of NO, how can you show
people that your new approach is comparable to a standard approach?
(B) To determine the concentration of an analyte vs. time in a biological
sample, electrochemical (A) and absorbance (B) methods are chosen.
The results are:
Time(min)
10 20 30 40 50
A(M) 0.022 0.041 0.062 0.088 0.102
B(M) 0.023 0.044 0.067 0.090 0.110
1. Is the null hypothesis retained based on the statistical data shown
in question (A) between methods A and B?
2. How can you estimate the concentration of the analyte after 60 min by
method B?
V. Detection limit (12pts, 4pts)
Pure water containing no arsenic was spiked with 0.40μg arsenate/L. Several
replicate determinations gave 0.39, 0.40, 0.42, 0.41, 0.38, 0.37, 0.43, and
0.36μg arsenate/L.
1. Find the mean percent recoveryof spike.
2. Find the concentration detection limit.
3. Estimate the lower limit of quantitation.
VI. Standard addition and internal standard methods (28pts, 4pts each)
1. Differentiate the two methods.
2. Which one is more suitable when the concentration of Pb2+ in a complicated
sample solution is determined? Why?
3. What are the criteria for applying a standard addition method?
4. What are the criteria for applying a internal addition method?
5. Which one is more suitable when several analytes in aqueous solution are
determined by gas chromatography?
6. How can the concentration of an unknown be determined when applying a
standard addition method?
7. How can the concentration of an unknown be determined when applying an
internal standard method?
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total: 244 points
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