19 - modern analytical techniques

Question 1

high resolution mass spectrometry

Answer 1

HRMS - type of mass spec that can produce Mr values with several decimal places, usually 4 or more

Question 2

nuclear magnetic resonance spectroscopy

Answer 2

technique used to find the structures of organic compounds. it depends on the ability of nuclei to resonate in a magnetic field

Question 3

chemical shift

Answer 3

chemical shift of proton (or group of protons) is a number (in ppm) that indicates its behaviour in a magnetic field relative to tetramethylsilane. it can be used to identify the chemical environment of the carbon atoms or the hydrogen atoms (protons) attached to it

Question 4

chemical environments

Answer 4

of carbon atoms in a molecule are related to whether the carbon atoms are identically or differently positioned within a molecule

Question 5

peak

Answer 5

in an H NMR spectrum shows the presence of hydrogen atoms (protons) in a specific chemical environment

Question 6

integration trace

Answer 6

shows the relative numbers of equivalent protons (i.e. in the same chemical environment)

Question 7

equivalent protons

Answer 7

hydrogen atoms in the same chemical environment

Question 8

splitting pattern

Answer 8

the appearance of a peak as a small number of small sub-peaks very close together

Question 9

multiplets

Answer 9

the different splitting patterns observed (singlets, doublets, triplets, quartets)

Question 10

stationary phase

Answer 10

in paper chromatography is the liquid or solid that does not move

Question 11

mobile phase

Answer 11

the liquid that moves through the stationary phase and transports the components