课程名称︰分析化学丁
课程性质︰必修
课程教师︰张焕宗
开课学院：理学院
开课系所︰化学系
考试日期（年月日）︰2015.05.07
考试时限（分钟）：180
试题 :
(I) Comparison: (18 pts, 3 pts each)
(1) Fluorescence and phosphorescence
(2) Absorption filters and Interference filters
(3) Prism and grating
(4) Molecular absorption profiles and atomic absorption profiles
(5) MALDI and ESI
(6) Chemical ionization and electron ionization
(II) Absorption and fluorescence (15 pts)
(1) Schemes for absorption and fluorescence spectrometers. You must clearly
provide names for the light sources and detectors. (6%)
(2) Why is a PMT more useful to improve sensitivity in fluorescence than in
absorption? (3 pts)
(3) How does the intensity of a light source affect absorption sensitivity?
(3 pts)
(4) Why is it important to measure absorption at the wavelength of maximum
absorption? (3 pts)
(III) Use a graph (scheme of plot) to answer each of the following questions.
No explanation is required, but important parameter (such as names of X
axis and Y-axis, the end point, the meaning of slope, and so on) must be
provided briefly. (27 pts, 3 pts each)
(1) Isobestic point.
(2) Spectrometric determination of the concentrations of Bi3+ and Cu2+ in an
aqueous solution containing the two metal ions.
(3) Deviation of Beer's law due to scattering light.
(4) The mass analyzer of MS^2.
(5) An internal standard MS method using gold nanoparticles as the matrix.
(6) A Scatchard plot.
(7) Fluorescence quenching at a high concentration of the analyte.
(8) An absorption spectrum to show aggregation of gold nanoparticles.
(Assuming well dispersed gold nanoparticles have λmax at 520 nm)
(9) ELISA
(IV) Methodology (18 pts, 3 pts each)
(1) Determine the n values of MLn. (注：n为下标)
(2) Determine the concentration of oxygen.
(3) Determine the concentration of ATP.
(4) A chemiluminescence method for the concentration of antigen.
(5) An absorption method for the determination of the concentration of iron.
(6) A spectrometric method for the determination of the dissociation constant
of an acid (HA and A- have different absorption wavelengths).
(V) Atmoic spectroscopy (27 pts)
(1) Use a scheme to show the differences among AAS, AES and AFS. (9 pts)
(2) The lowest excited state of a sodium atom lies 3.371*10^-19 J atom^-1
above the ground state. The degeneracies of the ground and excited states
are 1 and 2, respectively. What is the relative population at 2500K?
k=1.381*10^-23 J/K. (3 pts)
(3) Suggest a method to minimize the interference from the formation of
Ca3(PO4)2 when detection Ca2+ using a flame atomizer-AAS. (3 pts)
(4) Suggest a method to minimize ionization interference for the detection
of Ca2+.
(5) Suggest a method to validate an antique. (3 pts)
(6) Write down the three steps applied in an electrothermal atomization to
minimize matrix interference. (3 pts)
(7) Suggest a method to minimize salt interference when detecting Au using
ET-AES. (3 pts)
(VI) Application of UV-vis absorption (15 pts, 3 pts each)
Cefdinir (CFD) is a semisynthetic, broad-spectrum, third-generation
cephalosporin. It has a broad spectrum of activity, excellent therapeutic
action against susceptible Gram-positive and Gram-negative bacteria as having
potent antimicrobial activity, excellent efficacy, convenient dosing and
favourable tolerability compared with other antimicrobial agents.
Derivatization using NQS and NBD-Cl has attracted considerable attention for
quantitative analysis of many pharmaceutically active compounds. In the
present investigation, NQS and NBD-Cl form coloured complexes with CFD in
alkaline conditions and their absorbances were measured at 490 and 390 nm,
respectively. Because of the presence of amine as chromophoric group in CFD
molecule, derivatization of this compound was attempted in the present study
fir the development of spectrophotometric methods for its determination. NQS
and NBD-Cl have been used as chromogenic reagents for primary and secondary
amines; however, their reaction with CFD has not been investigated yet.
Therefore, the present study was devoted to explore NQS and NBD-Cl as
derivatizing reagents in the development of a spectrophotometric method for
the determination of CFD in pharmaceutical dosage forms.
http://i.imgur.com/K1fvVn1.png
http://i.imgur.com/SIV2ZIv.png
Note for the Absorption spectra: (1) the reaction product of CFD with NQS
against reagent blank and (2) NQS 0.1% (w/v) against methanol, (3) the
reaction product of CFD with NBD-Cl against reagent blank and (4) NBD-Cl 0.1%
(w/v) against ethanol.
(1) Why is it important to detect CFD?
(2) Why is derivatization of CFD with NQS or NBD needed?
(3) Is NQS or NBD-Cl better for the derivatization of CFD from the viewpoint
of minimum interference?
(4) Why is reagent blank used to against the absorption of CFD-NQS?
(5) Use a plot to show how the concentration of CFD can be determined in an
unknown sample.