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Modern analytical techniques
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- 1Give the 4 main stages of mass spectrometry-Vaporisation of the sample and insertion into Mass Spec.
-Ionisation of sample using high energy electron bombardment
-Seperation of molecules by m/z through time of flight
-Detection of molecules on -ive plate - 2What influences fragment abundanceThe stability of the fragment produced and the weakness of the bonds which bound the fragment to the molecule
- 3To what decimal place can High res mass spec measure RAM?4 decimal places
- 4How does IR spec produce a value?certain wavelengths of IR radiation are absorbed by specific bonds which is detected and projected onto a computer
- 5M is a compound that produces 2 products: M1 and M2 when its bombarded with electrons, what charges do these fragments have?[M1]+ [M2]. (free radical)
- 6Which of the products above are detected in the mass spec?[M1]+ only
- 7What does TMS stand for?Tetramethyl Saline
- 8What is TMS used for?A standard with which to compare other NMR values to
- 9What electromagnetic wave is used in NMR?Radiowaves
- 10What about the different chemical environments affects radio wave absorption?The amount of electron shielding provided by other atoms
- 11What is a chemical shift?The difference between the sample environment and the TMS value
- 12Give 2 reasons to do chromatography-To separate molecules in a mixture
-To identify individual molecules in a mixture - 13What is the mobile phase and what physical phase normally is it?The liquid or gas which transports the molecules
- 14What is the stationary phase and what physical phase normally is it?The solid phase which adheres/ absorbs the mixture preventing it from moving
- 15What does the retention time of the mixture depend onThe solubility of the mixture in the mobile phase and how well it binds to the stationary phase
- 16What is the equation for Rf?Distance travelled by spot
Rf=----------------------------------------------
Distance travelled by solvent - 17How can the Rf value be used for molecule identification?Rf value is constant for a specific molecule and solvent so comparison to data bank can identify molocule
- 18What does HPLC stand for>High-Performance Liquid Chromatography
- 19What is the stationary phase used in HPLCSilica or alumina beads
- 20What is the mobile phase used in HPLCA polar liquid
- 21How is HPLC conducted?Liquid mobile phase forced under pressure through collum containing silica beads. Sample injected and detected at the other end to find retention time
- 22How is Gas chromatography conducted?Sample injected into gaseous mobile phase and passed through heated coiled collum to a detector at the end.
- 23What is the stationary phase in GC?The solid/ Viscous oil which coats the coil which the sample binds to
- 24How can GC and mass spec be used together to identify a molecule?GC separates molecules in a sample and mass spec identifies them
- 25What does TLC stand for?Thin Layer Chromatography
- 26How is TLC conducted?Glass or plastic plate coated in silica or alumina acts as stationary phase and solvent carries molecules up the plate
- 27What biological molecule can be separated and identified through TLCAmino acids
- 28What is sprayed onto the TLC slide to identify the amino acids?Ninhydrin
- 29Why is Ninhydrin sprayed onto the slide?Amino acids are colourless. Ninhydrin identifies the amino acids
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- A-level (Modern analytical Techniques II) Chemistry Fichas sobre Modern analytical techniques, creado por Jack Rowe el 13/03/2021.
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- Jack Rowe
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