DMI: Difficult Matrix Introduction
GC analysis of dirty sample extracts and even row samples is now
possible with Difficult Matrix Introduction. No expensive and
time consuming cleanup is required with this technique.
DMI is based on the patented Direct Sample Introduction (DSI) technique*. It
enables sample introduction into GC column to be performed from a disposable
container (microvial) placed inside the injection liner. This has a great advantage
over traditional injection because large volumes (up to 30 µl) of dirty sample extracts
or even row samples can be introduced directly into GC or GC/MS. Using the principle
of selective exclusion, the volatiles and semi-volatiles are transferred onto the
column, while non-volatile residues are retained in the microvial, which is disposed
after analysis.
Ability to analyse sample by directly introducing the matrix or extract into the injector - little if any sample prep is involved
Liquid or dirty solid samples contained in a microvial which is inserted in an injector liner
Desorption from sample directly onto head of the GC capillary column - fewer steps involved, less opportunities for analyte losses
Solvents can be removed by venting under controlled conditions
Compounds of interest can be transferred onto the column using the lowest possible final temperature - limits pyrolyzing of matrix
Involatiles from the matrix are kept in the microvial which is disposed of after use - liner can be re-used
DMI steps:
*A. Amirav and S. Dagan, Eur. Mass Spectr., 1997, 3, 105-111.