Application of Solid Phase

Microextraction -Gas

Chromatography - Mass

Spectrometry in Flavor Research

David B. Min

Department of Food Science and

Technology

The Ohio State University

Columbus, Ohio USA

Isolation, Separation and

Identification of Flavor

Compounds of Edible Oil

Solid Phase Microextraction-Gas

Chromatography-Mass Spectrometry

Principle of Solid Phase Micro

Extraction

Equilibrium partitioning of the
flavor compounds between the
fiber and the headspace of
sample bottle.

A technique that uses a short, thin,
solid rod of fused silica, coated with
absorbent polymer for extraction of
volatile compounds.

The short, thin, solid rod of fused
silica, coated with absorbent
polymer is called fiber.

Solid Phase Micro Extraction for

Headspace Flavor Compounds

Isolation

SPME Principles for Headspace

Flavor Compounds Isolation

K

fh

V

f

V

s

C

o

K

fh

+

V

f

+

K

hs

V

h

+

V

s

n

f=

n

f

:

The

# of flavor compounds on

the fiber

K

: Partition coefficient

K

fh

=

V

f

,

V

s

,

V

h

:

Volume of fiber coating,

solution, and headspace,
respectively

C

o

:

Initial flavor concentration in

sample

Flavor concentration on
fiber

Flavor concentration in headspace

Fibers on the Volatile Compounds

Extraction

• CB/PDMS:
Carboxen/Polydimethylsiloxane

• PDMS:

Polydimethylsiloxane

• CW/DVB:
Carbowax/Divinylbenzene

• PA:

Polyacrylate.

Plunger

Barrel

Water bath

Coated fiber

Volatile Compounds Isolation by

SPME

Gas Chromatography-Mass

Spectrometry

Filters/Traps

A

ir

H

y

d

ro

g

e

n

G

a

s

C

a

rr

ie

r

Column

Gas Liquid

Chromatography

• gas system
• inlet
• column
• detector
• data system

Data system

Syringe/Sampler

Inlets

Detectors

Regulators

H

RESET

Principle of Gas Liquid

Chromatography

Partition of compounds between gas
mobile phase and liquid stationary
phase.

The compound which has high affinity
to the liquid stationary phase takes
longer to pass through the column than
the compound with less affinity to the
stationary phase of column.

Schematic Diagram of Gas

Chromatograph

Liquid Stationary Phases

1. Separation of mixture of polar

compounds

2. Separation of mixtures of non-polar

compounds

Flame Ionization Detector

High temperature of hydrogen flame (H

2

+O

2

+ N

2

) ionizes the separated

compounds eluted from column into
flame.

The ions are collected on collector and
detected as gas chromatographic peak.

Diagram of Flame Ionization

Detector

Exhaust

Flavor compounds from Column

Collector Electrode

Plunger

Barrel

Adjustable depth

gauge

Water bath

Coatedfiber

Volatile Compounds Isolation by

SPME

Effect of G.C.Injection Temperature on

Corn Oil Volatile Compounds Isolated by

SPME

230 °C

250 °C

Chromatograms of Corn Oil

Volatile Compounds Isolated by

SPME

Effect of Isolation Temperature on Corn

Oil Volatile Compounds by SPME

25°C

45°C

60°C

35°C

Isolation Time Effect on Corn Oil

Volatile Compounds by SPME

40

Isolation Time (min)

R

e

la

ti

v

e

P

e

a

k

S

iz

e

0

10

20

30

0

30

60

90

120

150

60

45

35

°C

°C

°C

Chromatograms of Soybean Oil and

Corn Oil

Soybean Oil

Corn Oil

Improving the Sensitivity of

Solid Phase Microextraction

•

Fiber Thickness

• Extraction Temperature and Time
• Selection of Proper Fiber
• Saturation of Sample with Proper Salts
• Maximum Ratio of Sample to

Headspace Volume
• Large Sampling Vial

Gas Chromatogram of Corn Oil Volatile

Compounds Isolated by Solid Phase

Microextraction

Gas Chromatography-Mass

Spectrometry

Principle of Mass Spectrometry

A mass spectrometer bombards a compound with an

electron

beam and quantitatively records the result as a spectrum of

positive ion fragments.

A mass spectrum is a presentation of the masses of the

positively charged fragments vs. their relative

concentration.

Gas Chromatogram of Corn Oil Volatile

Compounds Isolated by Solid Phase

Microextraction

Quadruple Mass Spectrometer

Fragmentations of 2-

Methylpentane by Electron

Bombardment

CH

3

CH

2

CH

2

CHCH

3

CH

3

m/z 86

+

•

Facile

Facile

More
difficult

CH

3

CH

2

CH

2

CHCH

3

CH

3

+

•

+

m/z
43

CH

3

CH

3

CH

2

CH

2

CH

CH

3

m/z
71

+

•

+

CH

3

CH

2

CH

2

CHCH

3

CH

3

+

•

+

m/z
57

Quadruple Analyzer for the

Separation of Positive Ion Fragments

Mass Spectrum of 2-

Methylpentane

In

te

n

si

t

y

m/z

20

40

60

80

100

10

20

30

40

50

60

70

80

90

43

57

71

86,
M

+

CH

3

CH

2

CH

2

CHCH

3

CH

3

Gas Chromatogram of Corn Oil Volatile

Compounds Isolated by Solid Phase

Microextraction

Corn Oil Volatile Compounds by SPME-

GC-MS

Pentane

1.29

13.03
Pentanal

1.88

5.52
Hexanal

3.62

5.39
Heptanal

5.36

1.83

2-Heptenal

6.21

29.52

2-Pentylfuran

8.59

2.53

2,4-Heptadienal

10.88

7.69
t-2-Octenal

11.51

18.07

Nonanal

13.88

6.27
t-2-Nonenal

14.23

1.33

2-Decenal

18.61

4.93

t,t-2,4-Decadienal

20.20

1.17

t,c-2,4-Decadienal

20.70

2.71

Compoun
ds

Retention Time

(min)

Relative
(%)

SPME - GC - MS