Analysis of Terpenes
in Cannabis Using the
Agilent7697A/7890B/5977B
Headspace GC-MSD System
Faster Analysis Time = Greater Productivity
Application Note
Authors
Ronald Honnold, Robert Kubas, and
Anthony Macherone
AgilentTechnologies, Inc.
2850 Centerville Rd
Wilmington, DE 19808
Cannabis, Food
Abstract
Terpenes and terpenoids are naturally occurring volatile isoprenes constructed
from a (C
5
H
8
)
n
building block where n is the number of isoprene units linked
to form linear or ring molecules. In marijuana (Cannabis sativa), terpenes are
biosynthesized in the flower along with other compounds such as psychoactive
∆
9
-tetrahydrocannabinol (THC) and other nonpsychoactive cannabinoids [1].
Each strain of marijuana is characterized by its unique terpene profile, that
creates the distinctive aroma and flavor [2]. This application note describes
the analysis of 22 terpenes common to marijuana in under 6 minutes using the
Agilent7697A/7890B/5977B headspace-gas chromatography-mass selective
detection (HSS-GC-MSD) system with concomitant flame ionization detector (FID)
detection using integrated Capillary Flow Technology to split the column effluent
in a controllable and precise manner to the two detectors.
2
Introduction
The concentration of individual terpenes in the C. sativa
plant varies by strain, harvest time, and drying and storage
conditions. Depending on these conditions, the relative
terpene concentrations decrease over time – for example,
after three months of storage, levels can decrease by more
than half [3,4]. Analysis of terpenes in C. sativa strains
is typically performed using HSS-GC/MSD, using the
AgilentResidual Solvent Analyzer hardware configuration
to provide an optimum linear range of detection and mass
spectral speciation.
Experimental
Hardware and consumables
• Agilent 7697A Headspace Sampler, Agilent 7890B GC with
FID, and Agilent 5977B MSD (Residual Solvent Analyzer)
• Split/Splitless Inlet
• Purged Two-Way Splitter: split 3:1 FID:MSD
• Agilent Headspace liner, Ultra Inert, splitless, straight
1mm (p/n5190-4047)
• Agilent 10 mL Headspace vials (p/n5190-2285)
• Agilent Headspace vial caps (p/n8010-0116)
• Agilent VF-35 column, 30 m × 0.25 mm, 0.25 µm
(p/nCP8877)
• MSD Restrictor - Deactivated Fused Silica
1.7 m × 150µm × 0 µm
• FID Restrictor - Deactivated Fused Silica
0.7 m × 250µm × 0 µm
Certified terpene reference standards 34095-DGEQ and
34096-DGEQ were obtained from Restek (Bellefonte, PA).
Agilent7697 Headspace parameters
Parameter Value
Instrument settings
Vial pressurization gas Helium
Loop size 1 mL
Keyboard lock OFF
Transfer line type DB-ProSteel
Transfer line diameter 0.53 mm
System configuration
Carrier control GC Instrument
Oven temperature 120 °C
Loop temperature 120 ��C
Transfer line temperature 140 °C
Vial equilibration 10.00 minutes
Injection duration 0.50 minutes
GC cycle time 10 minutes
Vial size 10 mL
Vial shaking Level 1
Fill mode Default
Fill pressure 15 psi
Loop fill mode Custom
Loop ramp rate 40 psi/min
Loop final pressure 13 psi
Loop equilibration time 0.05 minutes
Carrier control mode GC controls carrier
Extraction mode Single extraction
Vent after extraction ON
Post injection purge 100 mL/min for 3 minutes
Acceptable leak check Default, 0.2 mL/min
Agilent 7890B GC conditions
GC oven temperature 60 °C
Hold time 0.5 minutes
Oven program 45 °C/min to 150 °C, hold 0 minutes
then 35 °C/min to 250 °C, hold 0.5 minutes
Equilibration time 1 minute
Max temperature 260 °C
Column flow 3.0 mL/min
Front S/SL inlet He mode Split
Heater 220 °C
Pressure 29.45 psi
Total flow 303 mL/min
Septum purge flow Off
Gas saver 30 mL/min at 15 minutes
Split ratio 100:1
MSD Transfer line 260 °C