代做APH402 Homework 2代做留学生SQL语言

APH402 Homework 2

Due on Monday, December 23, 2024

Question 1. Give your understanding on the following:

1)  Mass Spectrometry. [10 marks]

2)  Major components of Mass Spectrometers and their functions. [10 marks]

3)  The working principles of EI, ESI, MALDI, QQQ, and ToF. [50 marks]

4)  Applications, advantages and disadvantages of Mass Spectrometry. [30 marks]

Question 2. Read the reference paper attached (L. Qu et al. Fitoterapia 78 (2007) 200–204.) and answer the following questions (Caution,there maybe some typo in the paper!):

1)  Draw the chemical structures of the six isoflavones from Dandouchi; [6 marks]

2)  Explain why the crude extract can be separated into two fractions by varying the concentration of ethanol in the mobile phase; [10 marks]

3)  Explain difference of mobile phases used for the analysis of Fraction 1 and 2;  [6 marks]

4)  Explain the retention order of the compounds in the two fractions; [12 marks]

5)  What is the function of 2% AcOH in the mobile phases?              [8 marks]

Question 3. An unknown compound, C13H18O2, has only one strong IR absorption peaks at 1741 cm-1. The 1H and 13C{1H} NMR, COSY, HSQC, and HMBC spectra of the compound recorded in CDCl3 at 298 K and 500 MHz are given below.

1) Derive the structure of the compound by using the data provided. For each 2D spectrum, indicate which correlation gives rise to each cross-peak by placing an appropriate label in the box provided (e.g. H1  → H2, H1  → C1) on the diagrams and  submit the diagrams together with your answer booklet. [30 marks]

2) List 3 important peaks that would show in the mass spectrum of the compound. [6 marks]

1H NMR spectrum (CDCl3, 500 MHz)

13C{1H} NMR spectrum (CDCl3, 125 MHz)

1H–1H COSY spectrum (CDCl3, 500 MHz)

1H-13C HSQC spectrum (CDCl3, 500 MHz)

1H-13C HMBC spectrum (CDCl3, 500 MHz)

Question 4. An unknown compound, C10H12O3, has only one strong IR absorption peaks at 1720 cm-1. The 1H and 13C{1H} NMR, COSY, HSQC, and HMBC spectra of the compound recorded in CDCl3 at 298 K and 500 MHz are given below. Derive the structure of the compound by using the data provided. For each 2D spectrum, indicate which correlation gives rise to each cross-peak by placing an appropriate label in the box provided (e.g. H1  → H2, H1  → C1) on the diagrams and submit the diagrams together with your answer booklet. [30 marks]

1H NMR spectrum (CDCl3, 500 MHz)

13C{1H} NMR spectrum (CDCl3, 125 MHz)

1H-1H COSY spectrum (CDCl3, 500 MHz)

1H-13C HSQC spectrum (CDCl3, 500 MHz)

1H-13C HMBC spectrum (CDCl3, 500 MHz)