User`s guide

Introduction
13
Introduction
IMPORTANT: Throughout this manual. TD refers to the
manual single-tube Thermal Desorber instrument. ATD refers to
the automated 50 tube Thermal Desorber Instrument.
Thermal desorption is a technique that extracts volatiles from a non-
volatile matrix by heating the matrix/sample in a stream of inert gas.
The extracted volatiles are subsequently refocused onto a cold trap
from which they are transferred in a narrow band to a gas
chromatographic column for analysis.
The sample is contained in a small capped tube. The ATD takes a
sample tube, uncaps it and seals it in the carrier stream. A leak test is
automatically performed to ensure that the tube has been sealed
correctly and to ensure that the rest of the system is leak-tight. The
tube is then purged with carrier gas at ambient temperature to
remove oxygen and moisture. The sample is subsequently heated
with a flow of inert gas to extract the volatiles. The volatiles are
concentrated on a low thermal mass, electrically cooled cold trap
prior to transfer to the gas chromatographic column through a heated
transfer line.
Heating the cold trap rapidly ensures that the analytes are transferred
to the gas chromatograph quickly. This sample transfer method is
fully compatible with high-resolution capillary chromatography.
The ATD is an automatic thermal desorption system that can handle
up to 50 samples. The automation system can be programmed to run
a series of tubes according to preset methods. The ATD also comes
standard with BCD output capability, which is optional on the TD.
The TD performs the same automated sampling as the ATD, but
handles one tube at a time. It provides cost-effective analysis of a
single tube. Standard PerkinElmer tubes can be loaded into the
instrument. You can upgrade the TD to an ATD if your application
changes.
Five different PerkinElmer® TurboMatrix™ Thermal Desorber
(TD) models are available: