所屬科目:研究所、轉學考(插大)-分析化學
1. Which type of chromatography was first invented in the history of chromatography?(A) Adsorption chromatography(B) Gas chromatography(C) Size-exclusion chromatography(D) None of the above
2. Which ionization method is most commonly and suitably used when coupling a gas chromatograph with a mass spectrometer?(A) Atmospheric pressure chemical ionization(B) Electrospray ionization(C) Electron ionization(D) Fast atom bombardment
3. What typically happens if a complex mixture is analyzed using a constant, low column temperature in gas-liquid chromatography?(A) All peaks become sharper(B) High-boiling analytes may not elute or may produce very broad peaks(C) Low-boiling analytes will not elute(D) The detector stops functioning
4. When light enters glass from air, which property of the radiation remains constant?(A) Velocity(B) Wavelength(C) Frequency(D) All of the above
5. Why is population inversion necessary for laser action?(A) It ensures absorption dominates over emission(B) It allows spontaneous emission to exceed stimulated emission(C) It increases the frequency of the emitted photons(D) It ensures more populations are available for stimulated emission than for absorption
6. Echelle gratings are often used in which type of analytical instrument?(A) Simple infrared absorption spectrometers(B) Fluorometers(C) High-resolution atomic emission spectroscopic systems(D) Colorimeters
7. Which of the following statements is an advantage of energetic inductively coupled plasma sources used in atomic emission spectroscopy?(A) Low chemical interferences(B) High chemical interferences(C) Ability to detect only one element at a time(D) Narrow concentration range
8. Which analytical technique commonly employs the Zeeman effect for background correction?(A) UV-Vis absorption spectroscopy(B) Atomic absorption spectroscopy(C) Gas chromatography(D) Mass spectrometry
9. Which statement best explains why a bathochromic shift occurs for a $\pi \rightarrow \pi^{*}$ transition when solvent polarity increases?(A) Polar solvents destabilize both $\pi$ and $\pi^{*}$ states equally(B) The ground state $(\pi)$ is more polar and becomes more stabilized(C) The excited state $(\pi^{*})$ is more polar and becomes more stabilized(D) Polar solvents increase the energy gap between $\pi$ and $\pi^{*}$
10. Which of the following statements about a quadrupole mass analyzer is TRUE?(A) A quadrupole mass filter generally offers low-to-moderate resolving power, typically around unit mass resolution.(B) A quadrupole mass analyzer routinely achieves ultrahigh resolving power exceeding 100,000.(C) Quadrupole mass analyzers surpass FT-ICR and Orbitrap instruments in mass resolution.(D) A standard quadrupole mass analyzer is designed to measure ions with extremely high $m/z$ values (e.g., $>10,000$) without special modifications.
11. Which of the following statements is incorrect?(A) Electrospray ionization is a suitable ionization method for analyzing protein samples.(B) Atmospheric pressure chemical ionization is suitable for the analysis of protein samples.(C) Matrix-assisted laser desorption/ionization mass spectrometry is suitable for the analysis of protein samples.(D) Fast atom bombardment is operated under vacuum.
12. Select ionization method(s) (electron ionization (EI), chemical ionization (CI), matrix-assisted laser desorption/ionization (MALDI), and electrospray ionization (ESI)) that are suitable for the analysis of thermal labile and polar analytes.(A) EI and CI(B) EI and MALDI(C) EI and ESI(D) ESI and MALDI
13. What is the main advantage of attenuated total reflection infrared (IR) spectroscopy compared with traditional transmission IR?(A) It provides higher resolution.(B) It works well for solids or films.(C) It increases the penetration depth of IR radiation.(D) It eliminates the effect of refractive index differences.
14. Which statement correctly describes how analytes are retained on different stationary phases in liquid chromatography?(A) In reversed-phase LC, hydrophobic stationary phases attract polar analytes through strong dipole-dipole interactions.(B) In normal-phase LC, analytes with higher polarity exhibit stronger retention because they interact more strongly with the polar stationary phase.(C) In ion-exchange chromatography, retention is dominated primarily by hydrophobic interactions between analytes and the stationary phase.(D) In size-exclusion chromatography, smaller analytes elute before larger ones because they cannot enter the pores of the stationary material.
15. Which light source is most commonly used in mid-infrared absorption spectroscopy?(A) Deuterium lamp(B) Tungsten-halogen lamp(C) Globar(D) Hydrogen lamp
16. Which of the following statements about the sensitivity of test strips are correct?(A) Higher sensitivity means the strip can detect lower concentrations of the target substance.(B) A highly sensitive test strip is less likely to produce false negatives.(C) Sensitivity refers to the ability to correctly identify negative samples.(D) Higher sensitivity is ideal for early-stage detection.(E) Sensitivity is more important than specificity in a low-risk area for disease transmission.
17. Which of the following statements correctly distinguish among the three quantification methods?(A) The external standard method assumes that the sample matrix has no effect on the analytical signal, and uses a calibration curve generated from standards in a clean matrix.(B) The standard addition method is best when matrix effects (biological fluid like blood serum) are suspected.(C) The internal standard method requires that the standard be the same compound as the analyte, and requires plotting the ratio of analyte signal to internal standard signal.(D) The internal standard method compensates for variation in sample preparation or instrument drift, which is suitable for the GC-MS method with inconsistent injection volume.(E) The standard addition method requires a separate blank matrix for calibration and then plots signal versus added concentration to find the original concentration.
18. A researcher compares the average amount of daily screen time between teenagers and adults. Which of the following statements are correct? (A) The null hypothesis would state that there is a big difference in screen time between the two groups. (B) A very significant t-test result (p < 0.01) would suggest rejecting the null hypothesis. (C) A smaller confidence level would result in a wider confidence interval. (D) An F-test must be performed before the t-test to validate equal variances. (E) A high F value suggests the two groups have the very similar daily screen time with a lower Q value.
19. Environmental scientists monitor water pollutants using UV-Vis and IR spectroscopy. Which of the following reflect appropriate uses of these techniques? (A) IR can quantify nitrate contamination in water by its characteristic absorbance. (B) IR spectra help identify functional groups like $-\mathrm{OH}$, $-\mathrm{C}=\mathrm{O}$, or $-\mathrm{C}=\mathrm{C}-$ in water pollutants. (C) Adding acid to the water leads to a blue shift in UV spectra of a pollutant, suggesting it's becoming less reactive or less conjugated. (D) Absorption increase in the UV spectra may indicate a breakdown of the dye structure. (E) IR can monitor the dye concentration over time using Beer's Law.
20. A patient with kidney stones is prescribed a citrate-rich drink to help reduce calcium oxalate precipitation in the urinary tract. Considering the solubility of calcium oxalate ($\mathrm{CaC_2O_4}$), which of the following statements are NOT true regarding how pH affects its solubility and the equilibrium involved? (A) Lowering the pH increases the solubility of calcium oxalate by protonating the oxalate ion ($\mathrm{C_2O_4^{2-}}$). (B) The solubility equilibrium includes both the Ksp expression and the acid-base equilibrium of oxalate. (C) Raising the pH causes calcium oxalate to dissolve more readily due to increased $\mathrm{OH}^-$ concentration. (D) Adding EDTA can shift the dissolution equilibrium toward more dissolved ions. (E) The mass balance expression: $$ [\mathrm{Ca^{2+}}] = [\mathrm{C_2O_4^{2-}}] - [\mathrm{HC_2O_4^-}] + [\mathrm{H_2C_2O_4}] = \text{solubility} $$
21. Which of the following normal modes of ethylene are NOT active in the infrared? (A) (B) (C)(D) (E)
22. Which of the following statements about Surface-Enhanced Raman Scattering (SERS) are correct? (A) SERS significantly enhances Raman signals by using nanostructured non-metal surfaces, typically silica (B) The enhancement in SERS arises mainly from two mechanisms: electromagnetic enhancement and chemical enhancement. (C) SERS requires that the analyte molecule has a permanent dipole moment to exhibit enhancement. (D) The electromagnetic enhancement in SERS is primarily due to surface plasmon resonance in nanostructures. (E) SERS enables detection of very low concentrations of analytes.
23. Which of the following statements correctly describe features and processes represented in a Jablonski energy diagram? (A) Phosphorescence violates Kasha's Rule because it originates from the triplet state rather than the singlet state. (B) Phosphorescence is a radiative transition from a triplet state to the ground singlet state, typically slower than fluorescence. (C) According to Kasha's Rule, vibrational relaxation happens much faster than fluorescence. (D) Kasha's Rule states that fluorescence typically occurs from the lowest excited singlet state $(\mathrm{S}_1)$, regardless of which higher singlet state was initially excited. (E) Fluorescent dyes usually exhibit the Stokes shift as compared to their absorption wavelengths.
24. Which of the following statements about the use of Fourier Transform in spectroscopy are correct? (A) Fourier Transform is not applicable to nuclear magnetic resonance (NMR) spectroscopy because NMR data is already in the frequency domain. (B) In FTIR spectroscopy, a moving mirror is used in a Michelson interferometer to generate an interferogram from the incoming light. (C) Fourier Transform Infrared (FTIR) spectroscopy uses an interferometer to collect time-domain (interferogram) data, which is then converted to a frequency-domain spectrum. (D) Fourier Transform allows simultaneous measurement of all wavelengths, improving signal-to-noise ratio. (E) The signal-to-noise ratio is irrelevant to the number of measurements.
25. Which of the following statements correctly describe the IR and vibrational Raman activity of the listed molecules based on vibrational selection rules? (A) CO₂ has both IR-active and Raman-active vibrational modes. (B) H₂O shows IR activity because its vibrations involve changes in dipole moment. (C) N₂ is IR active because it has a symmetric stretch that changes the molecule’s dipole moment. (D) CH₄ doesn’t exhibit Raman-active modes. (E) O₂ is Raman active but IR inactive.
26. Which of the following statements correctly describe the rotational spectral activity of the listed molecules in microwave and rotational Raman spectroscopy, based on selection rules? (A) CH₄ shows rotational P/R branches in microwave spectroscopy because of its symmetric tetrahedral structure. (B) O₂ is both microwave and rotational Raman active because its symmetric stretch changes. (C) HBr is active in microwave spectroscopy because it is a heteronuclear diatomic molecule. (D) N₂ is microwave inactive but rotational Raman active. (E) CO₂ can show rotational Raman spectra but is microwave inactive due to its linear and centrosymmetric structure.