I was previously working in a lab preparing lots of samples for gas chromatography that exclusively used glass pipettes and was able to get really high precision between replicates. Now I'm working on my own project doing a lot of liquid dilutions that need to be very accurate with an older pipette that I am looking to potentially replace for better results. I'm specifically looking at 1 mL volumes.

Tolerances for glass syringes seem to be about +/-1% (not as much info), where pipettes are +/-0.6% accuracy and +/-0.2% precision. There were definitely some other reasons to use syringes vs pipettes at my old lab, but are syringes really always outclassed by pipettes? Can an experienced syringe operator beat a pipette?

I realize tip choice, needle, calibration, and ambient temperature controls probably have larger effects than these differences (though seemingly favor syringes), so I am wondering more about the relative optimal performance of each.

  • $\begingroup$ If evaporation is not a significant influence (depending on solvent's boiling temperature / concentration / exposed liquid area, temperature around, etc.) you might consider to determine the $\Delta{}m$ of tare of the syringe and filled syringe to substitute volume by mass and gravity. $\endgroup$
    – Buttonwood
    Jul 8 '20 at 21:10
  • $\begingroup$ Always? It is difficult to use a pipette to inject into a port for a GC, or GC/MS. $\endgroup$
    – MaxW
    Jul 8 '20 at 21:18

Glass syringes and glass pipettes are high precision and high accuracy tools of an analytical chemist. Like any tool at home, such as a cloth cutting scissor and a plant pruning clipper do the same job of cutting but their applications are different.

As an analytical chemist, I have not seen anyone using microsyringes for standard preparations in volumetric flasks. One uses a class A pipette for volumetric transfers and to make different standards.

Now you wish inject known microliter or nanoliter volumes in a GC injection port or an HPLC rheodyne, can we use glass pipettes? You would choose a glass syringe to pierce the GC septum.

The tip is that you would use the highest quality glass pipette (class A) and highest quality syringes in each case. class A 1 mL pipettes are commercially available.

If you really wish to compare, you would have to do a calibration yourself on a analytical balance under tightly controlled conditions.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.