I work in a laboratory where gas chromatography is used extensively. We handle phthalates. What are the possible wash solvent for autosampler syringe? I've been using acetone.

  • $\begingroup$ You could try use toluene a then ethyl acetate. $\endgroup$ Sep 4, 2019 at 12:46
  • $\begingroup$ Acetone is a remarkable solvent. Now if you use some phthalates which are either particularly polar or particularly non-polar, you may want to change the solvent. For really polar compounds, a mixture of methanol/water/acetonitrile may be great. For non-polar compounds, you may want to use dichloromethane. $\endgroup$
    – SteffX
    Nov 16, 2019 at 13:29
  • $\begingroup$ I think Waters used to suggest a magic mix of 1:1:1:1 MeOH:IPA:ACN:water with a few drops of ammonia as a good way of clearing pthalates from lines - the same likely applies to autosampler needles $\endgroup$
    – NotEvans.
    Nov 4, 2021 at 21:22

2 Answers 2


Well, since you have a GC, any volatile solvent for phthalates is good, it may show up as a peak on the chromatography.

If you are not analyzing for the solvent, it is all right. If one is, switch to another solvent!

Also make sure any cleaning solvent is compatible with the injector diaphragm, syringe, column, or any other parts of the instrument.

It would not hurt to make a few consecutive injections with your sample preparation solution only just to make sure before starting the analytical injection sequence.


Methanol is less expensive. Don’t know how well it would work in your particular situation. We do semi volatiles (EPA 624) . Methanol works fine for the GC autosampler syringe.


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