Extraction Technologies for Medicinal and Aromatic ... - Capacity4Dev

EXTRACTION TECHNOLOGIES FOR MEDICINAL AND AROMATIC PLANTS
9 Solid Phase Micro-extraction and
Headspace Trapping Extraction
Abstract
R. Harlalka
Solid phase micro-extraction (SPME) is a technique used in the quantitative analysis of
analytes in aqueous and gaseous phases. This novel technology captures aroma molecules
surrounding fl ower petals without touching the fl ower or other part of the plant.
SPME has gained widespread acceptance as the technique of choice in many fi elds
of application, including forensics, toxicology, and the analysis of fl avors, fragrances,
and environmental and biological matrices. SPME is ideal for fi eld monitoring. SPME
sampling can be performed in three basic modes: direct extraction, headspace trapping
and extraction with membrane protection. Headspace trapping is essentially a
gas extraction technique permitting the direct analysis of volatile compounds present
in a non-volatile matrix. This technique is needed because the aromas of living plant
materials are different from those of the extracted oil. Headspace trapping permits
getting closer to the natural aroma of the living plant, and gives a clearer view of the
differences in volatile constituents between the living plant and the extracted phase.
There are two types of headspace trapping: static and dynamic, which is also called
the purge-and-trap method. A few examples of headspace trapping of well known aromatic
fl owers, fruits and leaves, in comparison to the analyses of the extracted oil, are
presented in this paper. Some classical perfumes are also discussed.
9.1 Introduction
Solid phase micro-extraction (SPME) was developed in the
1990s by Professor J. Pawliszyn to provide a quick and solventless technique
for the isolation of analytes from a sample matrix. The traditional
methods by which the analytes of interest were isolated are typically timeand
labor-intensive and involve multistep procedures, which could reduce
sensitivity. Also, the use of solvents can be hazardous to the operators’
health and can damage the environment.
SPME was developed from the technique of solid phase extraction,
but the sorbing material is permanently attached to the fi ber, allowing
reuse of the extracting phase. SPME uses a small volume of sorbent, typically
dispersed on the surface of small fi bers, to isolate and concentrate
analytes from the sample matrix. After contact with the sample, analytes are
absorbed or adsorbed by the fi ber phase (depending on the nature of the
coating). After the extraction step, the fi bers are transferred, with a syringelike
handling device, to the analytical instrument, for separation and quantifi
cation of the analytes. This technique integrates sampling, extraction and
sample introduction, and is a simple way of performing on-site monitoring.
Applications of this technique include environmental monitoring, fragrance
drug analysis, and in-laboratory and on-site analyses.
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