Summary - Unit 19 - Modern Analytical Techniques II

MODERN ANALYTICAL TECHNIQUES #


HIGH RESOLUTION MASS SPECTROMETRY
↳ measure relative mass to several decimal places



Mr > Mr
e .
g (H3CH0-44 0302 Mr
whole
.
.


whole no
. no

3348-44 0624 Mr
Mr 10 dp)
.

=
same .




SPECTROMET I
NMR
A odd no . of protons and neutrons 'M : I proton , Oneutron
CH3
>
-


gives good sign
↳ small mount




13C NMR High Res H NMR nuclear
13
C : G proton 7 neutron inert
I
.
,

spin isotope
↓ ↓ non-toxic




⑳
how carbon atoms volatile H
hydrogen atoms
, -Si-CH
are are
how
amanged arranged
-
easy to remove
↳ Hy
FACTORS AFFECTING NMR age

field
magnetic tetramethylsilane (TMS
shielding from surrounding e-
&
-




neighbouring atoms affect shielding
I
-




↑




·
Ot will reduce
shielding of 28 + MAG FORCE
2 .


.
g NO EXTERNAL FORCE EXTERNAL .
energy
full chain NMR
X
NOT just immediately ↑ fires ↓ ↓ ↓ ↓ ↓ ↓
bonded ↓ + X
r a d i owave s

=>
-I
4 Bo n un 44 F
444 Nuclei spin in random
111 more

H -
c - c -
c -
H -
c -
c -
c -
Bon - C c - -
Br Br - c -
C -
Br
directions
aligned with
MF So


I i
move is absorbing

i in in i in radio waves
nuclei Spin either :


in direction of the magnetic field
↓
-




field
what's
·
against direction of the magnetic
this is
2 carbon 3 carbon 2 1 measured
environments
hydrogen hydroges
environments enviroments environment




CARBON NMR SPECTROMETRY

This table will be provided :

H H
13
CNMR but
peal at 190 is a
carbonyl group
chemical Shif 6/ppm
I I puseaway
bite samea field could be :




/
3 40 C C
C C
-

H c
-

- - -




I I
-




↳highera 10-70 R-C-C)
O
(orBu) -

aldehyde
↳6 lower
20-50 -
net one
I H
L XTMS R- -
8
chemical
shift
25 -
60 R -
C - N peal at 60 is a C-O group but
208 ISO 100 so o 208
could be :
50-90




#
C -
O
A chem
alcohol
90 C C
-


-

150 =
-

ester
110-125 R-CEN
13
CNMR -
ether
110-168 n
ro
V
160-185 carboxylic acid
r -
- /ester
g
190-220 11
aldenyde/
OXTMS R C -



netune
-




200 ISO 100 So




ELEMENTAL ANALYSIS


HYDROGEN NMR SPECTROMETRY
n
>
-
determines %
composition
mass of elements that make a compound
integration trace : -

'H NMR 3 helps show the
> determines
H molecular/empirical
-



vario of formula




/
are a

I
G peaus ↳
x3 height for structure can be determined
T
H -
c -
C sometimes called
- ~ decimals
I O -
H
H -
1
THIN LAYER CHROMATOGRAPHY
5 CHRO
Oxims
-
of




in
20 IS 10




>
so



Mixin spots dissolve

C - more once the some -




-
is

Yu
near the top
H NMR singlet peal
~


Oh neighbouring the solvent level
allow to
dry
>
-




doublet pean-
I I
triplet peak-
1 h neighboringaa
n - c -
c -
O -
H quartet -
peau 3 I neighbouring
11

un
GAS CHROMATOGRAPHY
20 Is 10 s O

eator