Objective:

2

Headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to analyze the characteristic volatile compounds from 18 heat-clearing herbs.

Method:

2

HS-SPME was used to extract the volatile components from different heat-clearing herbs

and the chemical compositions were analyzed by GC-MS. The GC was performed at the injector temperature of 250℃

the high-purity helium was used as the carrier gas at a constant column flow of 1.0 mL·min

-1

with no split sampling. The solvent delay time was 3 min. Mass spectrum conditions included electron bombardment ion source

electron bombardment energy of 70 eV

ion source temperature of 230℃

quadrupoles temperature of 150℃

and scanning range of

m

/

z

29-370.The volatile components were confirmed according to NIST2013 database

and the relative content percentage of each component was calculated by peak area normalization method. PCA was used to detect clustering and discuss the characteristics of volatile compounds of 18 heat-clearing herbs.

Result:

2

A total of 328 volatile compounds were detected in 18 heat-clearing herbs

including alkanes

unsaturated hydrocarbon

alcohols

aldehyde

ketones

esters

furan and other unknown compounds. The number and relative content of volatile components in different heat-clearing herbs varied dramatically. Several important characteristic volatile compounds

such as

l

-camphor

torreyol

caryophyllene oxide

globulol and 2

4-cycloheptadien-1-one

2

6

6-trimethyl

were detected in the 18 heat-clearing herbs by principal component analysis.

Conclusion:

2

Heat-clearing herbs contains rich volatile components

which are the main contributors to the formation of unique aroma of herbs

as well as the main active substances.