HT2800T_en_c.doc Page 229 of 275
8.19.2.2 Contamination or ghost peak issue
Possible causes
Solutions
Vial cap septum dissolution in
solvent (small fragments of
septum were dissolved in the
sample).
Inject several blanks to check for ghost peaks persistence or elimination.
Check that: the syringe needle hasn't burrs that can cause septum
cutting ; septum resistance to the solvent in use; the septum is flat (see
paragraph 3.7.2).
Contamination in sample vials Try to use new or clean vials. Store new vials in a contaminant-free place
Sample instability Check the stability of the samples,and ensure they are not sensitive to
light or heat. Ensure they are stored correctly.
8.19.2.3 Peak size issue
Possible causes
Solutions
Leak in the GC system
Replace the septum and check the fitting to verify leak presence. If the
septum had experienced less than 100 injections, check the following
elements to avoid premature septum problems: the syringe needle is not
straight; the septum retainer nut is too tight; the syringe has not been
installed in the correct way.
Sample instability Check the stability of the samples, and ensure they are not sensitive to
light or heat. Ensure they are stored correctly.
The vials are not closed
properly
Check the caps of the vials. Loose caps may cause volatile solvents to
evaporate and change the sample concentration over time (see
paragraph 3.7.2).
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