Addendum to PAL User Manual Installation and ... - PAL System

E. PAL ITEX-2 Option Installation
1. General System Overview
Figure 1. PAL ITEX-2 Option.
Addendum to PAL System User Manual
PAL ITEX-2 Option
The PAL ITEX-2 Option is an add-on module for the PAL and PAL-xt Systems
to extend the range of headspace techniques. ITEX can be considered an
automated dynamic headspace technique. In classical headspace technique,
one sampling is done per vial. In this device, analytes are adsorbed (loaded)
on a sorbent trap contained within a side-hole needle attached to a gas-tight
syringe. Following this loading procedure, analytes are thermally desorbed
and led directly into the GC injection port, then analyzed by the required
technique, mainly using GC-MS detection.
Loading takes place by continuously moving the headspace syringe plunger
up and down, passing the headspace gas phase that exists above a sample
through the sorbent trap inside the needle numerous times.
Dynamic headspace extraction increases the concentration of analyte in order
to extend the range of detection as compared to conventional static
headspace techniques. Required levels of detection can be reached by
applying more pumping (up and down) cycles. To reach the detection limit in
the range of a ppm to ppb concentration, three to twenty strokes are typically
applied and, for the ppt-level of concentration, 40 to 60 pumping strokes may
be necessary.
The PAL ITEX-2 Option consists of a dedicated gas-tight syringe with an
adapter for a replaceable side-hole needle and a heated syringe cartridge.
The side-hole needle includes an integrated trap (standard trap material is
Tenax TA) and a trap/desorber heater.
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