GC-MS analysis of e-liquids taken from e-cigarettes and e-liquids

(e-juice) before use in e-cigarettes

John H. Lauterbach, Ph.D., DABT Lauterbach & Associates, LLC, Macon, GA 31210-4708 USA

Deborah A. Grimm, Ph.D. Coordinated Instrumentation Facility

Tulane University, New Orleans, LA 70118-5698 USA

2013

_ST

05_L

aute

rbac

h.pd

fS

SP

T20

13 -

Doc

umen

t not

pee

r-re

view

ed b

y C

OR

ES

TA

Objectives for this presentation • Identify major and minor species in e-liquids

using traditional GC-MS analytical techniques – Main aerosol-forming species (PG, VG) – Flavorful components – Unexpected components

• Determine if published ingredient information was consistent with analytical findings

• Attempt to identify compounds present that might account for the cytotoxicity reported in some e-liquids (Bahl et al., Reproductive Toxicology 2012 34:529-37)

2 L&ALLC ST05_CORESTA_2013

2013

_ST

05_L

aute

rbac

h.pd

fS

SP

T20

13 -

Doc

umen

t not

pee

r-re

view

ed b

y C

OR

ES

TA

Analytical approach • Capillary column gas chromatography – mass

spectrometry (GC-MS) has been main tool for analyses of flavors for more than three decades – Ability to separate and identify volatiles and semi-

volatile components of complex mixtures – Long history of use in tobacco industry for analyses

of flavor concentrates, finished flavors, and flavors applied to tobacco products

– Tobacco flavors and flavor concentrates often formulated in propylene glycol (PG)

• These factors make GC-MS the ideal tool for the analyses of e-liquids and their components

3 L&ALLC ST05_CORESTA_2013

2013

_ST

05_L

aute

rbac

h.pd

fS

SP

T20

13 -

Doc

umen

t not

pee

r-re

view

ed b

y C

OR

ES

TA

Peppermint flavor 1.2% Nicotine

DB-5 MS column Lab 1

Glycerol

Nicotine

Triacetin

Monoacetin

Caryophyllene

Diacetin

ST05_CORESTA_2013 L&ALLC 4

Example chromatogram 1a

2013

_ST

05_L

aute

rbac

h.pd

fS

SP

T20

13 -

Doc

umen

t not

pee

r-re

view

ed b

y C

OR

ES

TA

ST05_CORESTA_2013 L&ALLC 5

Example chromatogram 1b Peppermint flavor – TMS

1.2% Nicotine DB-5 MS column

Lab 1 Glycerol

Nicotine

PG

Menthol Carvone

2013

_ST

05_L

aute

rbac

h.pd

fS

SP

T20

13 -

Doc

umen

t not

pee

r-re

view

ed b

y C

OR

ES

TA

ST05_CORESTA_2013 L&ALLC 6

Example chromatogram 1c Peppermint flavor

1.2% Nicotine SolGel-Wax column

Lab 2

Glycerol

Nicotine

PG Menthol

Monoacetin

Triacetin Diacetin

Carvone

2013

_ST

05_L

aute

rbac

h.pd

fS

SP

T20

13 -

Doc

umen

t not

pee

r-re

view

ed b

y C

OR

ES

TA

Peppermint e-liquid

Vendor’s web page

Compound Amount

Propylene glycol Very Large

Malic acid Medium

Vanillin Medium

Acetyl pyrazine Small

Menthol Small

Ethyl acetate Small

Aliphatic acid Very small

Common flavors Very small

Found by analysis

Compound Relative amount

Propylene glycol Very large

Glycerol Large

Monoacetins Large

Diacetins Medium

Triacetin Medium

Menthol Small

Menthone Small

Carvone Small

Pulegone Very small

Anethol Very small

Caryophyllene Very small

ST05_CORESTA_2013 L&ALLC 7

2013

_ST

05_L

aute

rbac

h.pd

fS

SP

T20

13 -

Doc

umen

t not

pee

r-re

view

ed b

y C

OR

ES

TA

Example chromatogram 2a

ST05_CORESTA_2013 L&ALLC 8

Chocolate flavor 1.2% Nicotine

DB-5 MS column Lab 1

Glycerol

Nicotine

2013

_ST

05_L

aute

rbac

h.pd

fS

SP

T20

13 -

Doc

umen

t not

pee

r-re

view

ed b

y C

OR

ES

TA

Example chromatogram 2b

ST05_CORESTA_2013 L&ALLC 9

Chocolate flavor – TMS 1.2% Nicotine

DB-5 MS column Lab 1

Glycerol

Nicotine

Hexitol

PG

Di-PG

2013

_ST

05_L

aute

rbac

h.pd

fS

SP

T20

13 -

Doc

umen

t not

pee

r-re

view

ed b

y C

OR

ES

TA

Example chromatogram 2c

ST05_CORESTA_2013 L&ALLC 10

Chocolate flavor 1.2% Nicotine

DB-Wax column Lab 2

ISTD

Chocolate flavor 1.2% Nicotine

SolGel-Wax column Lab 2

Glycerol

Nicotine

PG

Di-PG

2013

_ST

05_L

aute

rbac

h.pd

fS

SP

T20

13 -

Doc

umen

t not

pee

r-re

view

ed b

y C

OR

ES

TA

Chocolate e-liquid

Vendor’s web page

Compound Amount

Propylene glycol Very Large

Vanilla extract Large

Terpene alcohol Medium

Acetyl pyrazine Small

Alkyl pyrazine Small

C-5 aliphatic acid Small

Common flavors Small

Found by analysis

Compound Relative amount

Propylene glycol Very large

Glycerol Medium

C-6 sugar alcohol Very small

Dipropylene glycol Very small

ST05_CORESTA_2013 L&ALLC 11

2013

_ST

05_L

aute

rbac

h.pd

fS

SP

T20

13 -

Doc

umen

t not

pee

r-re

view

ed b

y C

OR

ES

TA

Example chromatogram 3

ST05_CORESTA_2013 L&ALLC 12

Tobacco flavor – PG Free 1.8% Nicotine

SolGel-Wax column Lab 2

Glycerol

Nicotine

Syringol

Vanillin

EtVanillin

EtMaltol

Maltol Cyclotene

PG

Menthol

Acetic acid

2013

_ST

05_L

aute

rbac

h.pd

fS

SP

T20

13 -

Doc

umen

t not

pee

r-re

view

ed b

y C

OR

ES

TA

Lagniappe • Most information reported to date on the

mainstream e-cigarette aerosol (MECA) has focused on nicotine content and/or known smoke toxicants

• However, the same techniques that are used for analyses of e-liquids should be useful for analyses of major components of MECA – Collect MECA on Cambridge pad – Health Canada Intensive smoking – 100 puffs (≈ 90 mg) – Extract pad with 2-propanol containing

heptadecane as the internal standard (ISTD)

13 L&ALLC ST05_CORESTA_2013

2013

_ST

05_L

aute

rbac

h.pd

fS

SP

T20

13 -

Doc

umen

t not

pee

r-re

view

ed b

y C

OR

ES

TA

Example chromatogram 4

ST05_CORESTA_2013 L&ALLC 14

Chocolate flavor MECA 1.2% Nicotine

SolGel-Wax column Lab 2

Glycerol

Nicotine

ISTD

PG

Di-PG C-14 HC

2013

_ST

05_L

aute

rbac

h.pd

fS

SP

T20

13 -

Doc

umen

t not

pee

r-re

view

ed b

y C

OR

ES

TA

Example chromatogram 5

ST05_CORESTA_2013 L&ALLC 15

Tobacco flavor – MECA 1.8% Nicotine

SolGel-Wax column Lab 2

Glycerol

ISTD

Nicotine

? EtMaltol

Syringol

2013

_ST

05_L

aute

rbac

h.pd

fS

SP

T20

13 -

Doc

umen

t not

pee

r-re

view

ed b

y C

OR

ES

TA

Concluding remarks • Traditional GC-MS techniques for analyses of

flavors and smoke can be applied to e-liquids and mainstream e-cigarette aerosols (MECA)

• There were differences in e-liquid composition between what was expected and what was found – Are users getting the hedonic properties expected

by the manufacturers of the e-liquids? – Do e-liquid vendors have accurate information on

the composition of the products they are selling? – However, nothing to support report of cytotoxicity

• Is there sufficient flavor transfer for superior consumer satisfaction?

16 L&ALLC ST05_CORESTA_2013

2013

_ST

05_L

aute

rbac

h.pd

fS

SP

T20

13 -

Doc

umen

t not

pee

r-re

view

ed b

y C

OR

ES

TA

Acknowledgement

• Some of the GC-MS analyses reported in this presentation were performed by Dr. Andrae Spencer of Global Laboratory Services of Wilson, NC. The author would like to thank Dr. Spencer very much for his excellent scientific work on the GC-MS analyses.

• The lead author of this presentation and Lauterbach & Associates, LLC, are totally responsible for the content of this presentation.

17 L&ALLC ST05_CORESTA_2013

2013

_ST

05_L

aute

rbac

h.pd

fS

SP

T20

13 -

Doc

umen

t not

pee

r-re

view

ed b

y C

OR

ES

TA