3 25 Marks A 20 Marks A Perfume Is A Dilute Solution Of Volatile Fragrant Organic Compounds Dissolved In An Ethan 1 (43.48 KiB) Viewed 97 times
3. (25 marks) a) (20 marks) A perfume is a dilute solution of volatile, fragrant organic compounds dissolved in an ethanol/water mix. A researcher wishes to analyse two perfumes A and B by gas chromatography-mass spectrometry. The perfumes are of unknown composition but smell very similar, so the researcher wishes to determine exactly how similar they are. Design an appropriate analysis for this application using ONE of the alternatives given in each part 1)-ix). For each of 1)-ix), clearly state your choice of the alternatives, justify/explain why your choice is appropriate for this analysis and how the other choice may not be. Parts i)-viii) are worth 2 marks each and part ix) is worth 4 marks. i) neat liquid injection OR headspace analysis ii) split OR splitless injection iii) an initial column temperature of 50°C OR an initial column temperature of 100°C iv) isothermal chromatography OR use of a temperature gradient v) hydrogen as carrier gas OR helium as carrier gas vi) carrier gas flow rate of 0.8 mL/minute OR carrier gas flow rate of 9 mL/minute vii) SIM detection OR TIC detection viii) benzoin (molecular weight 212, common fixative in perfume) as an internal standard OR fluorobenzene (molecular weight 96, not found in perfume) as an internal standard. ix) additional detection by a thermal conductivity detector OR an electron capture detector (also indicate the appropriate sequence of your chosen detector with the mass spectrometer)
b) (5 marks) The two molecules given below are components of some perfumes. Explain in detail how you might distinguish between them on GCMS, using both their retention times and mass spectral parameters. HO A B
Join a community of subject matter experts. Register for FREE to view solutions, replies, and use search function. Request answer by replying!