a Structure of Mass Spectrometer AVaporization Chamber BIonization

(a) Structure of Mass Spectrometer • • • A=Vaporization Chamber B=Ionization Chamber C=Accelerating Chamber D=Deflection Chamber E=Ions detector

(a) Functions for each parts of Mass Spectrometer • A=Vaporization Chamber • B=Ionization Chamber • C=Accelerating Chamber • D=Deflection Chamber • to vaporize the sample to be tested by heat • molecules are bombarded by alpha/beta rays to form cations • cations are accelerated by a strong electric field • cations are deflected by strong magnetic field according to their mass/charge ratio • E=Ions detector • amounts of ions are proportional to the electric current detected

(b) Give two reasons why such kind of mass spectrometer cannot be used to determine the molecular mass of biomolecules. • (1) Because biomolecules are thermal labile, they would decompose in the evaporation chamber under strong heating • (2) The biomolecules would be cracked by the bombardment with alpha/beta rays in the ionisation chamber

(b) Name the two parts in the traditional mass spectrometer which were replaced by electrospray ionization (ESI) technique. Explain why such a technique can be used to study biological macromolecules. • ESI technique can replace the vaporization chamber and ionization chamber. • As no heating and bombardment with high energy particles to the bio-macromolecules are required by using electrospray ionization technique, the bio -molecules would not decompose.

(d) Name the two parts in the traditional mass spectrometer which were replaced by soft laser desorption (SLD) technique. Explain why such a technique can be used to study biological macromolecules. • SLD technique can replace the vaporization chamber and ionization chamber. • As no heating and bombardment with high energy particles to the bio-macromolecules are required by using soft laser desorption technique, the biomolecules would not decompose.

(e) State two advantages of applying ESI and SLD techniques in Mass Spectrometer to study biological macromolecules. • The method is superior to other methods in the rapidity, sensitivity and identification of the actual interaction. • This analytical methods are relatively cheap, enabling them to spread quickly to laboratories all around the world. • By having a surface that cancer cells adhere to – and then analysing this with soft laser desorption – chemists can discover cancer faster than doctors can.