Dear Micro pipette is being mostly used for exact volume. Please use sucker for taking volume. after poring must touch pipette's end with the surface of flask in this way you may completely transfer sample from pipette to flask.

thank you

Dear, Chau Phuong Bui,

Your problem may be dissolved by this recomendations: https://www.hamiltoncompany.com/automated-liquid-handling/everything-you-need-to-know-about-liquid-handling/tips-to-accurately-pipette-volatile-liquids

But as for me, the best solution is to change MeOH on DMSO.

You may need an electronic pipette to improve precision:

https://lab.plygenind.com/manual-vs-electronic-pipette-a-comprehensive-guide

The advice on getting the best out of a pipette on the Hamilton link above is excellent but using a pipette with volatile solvents is problematic and generally not recommended for the reasons that are clear in the Hamilton link. With volatile solvents an analytical syringe is a much better way to go and to achieve the ultimate precision and accuracy a motorised analytical syringe is by far the best. Using these devices 0.1%RSD or better can routinely be achieved for volumes between 50uL and 10mL, and even at 100nL volumes 0.5% RSD is achieved if you have a good enough method for making the measurement. There are two handheld motorised syringe solutions available, the eVOL and the digiVOL (www.digvol.com.au).

Why not using a balance instead a micropipette ?

The density of methanol is 792, if you need for example 50 ml, you have to weight 39,6 g.

Use 0 5, 1, 2, 4, 5mL and 10mL bulb glass pipette (Emil, Grade A) to take an exact volume

https://shop.brand.de/en/bulb-pipettes-usp-blaubrandr-class-as-1-mark-ar-glasr-blue-printed-scale-de-m-p336.html

Or

▪️use glass dropper or 200uL Electric pipette and electronics balance to deliver accurate volume of methanol (density of methanol is 0.7513 g/mL)

Hi,

Methanol has a low viscosity and vapor pressure. This makes it unique in pipetting with an automatic pipette (like most organic solvents). It takes a lot of experience to do it repeatedly. The most important thing is to pre-wet the pipette tip by aspirating and dispensing the pipetted liquid once. You can practice with analytical balance. You can also ask the supplier what type of tip he recommends for methanol (he will probably tell you that none). A better solution is an automatic micro-syringe. I have such a syringe and I think it is the best tool for microdosing. Unfortunately, I heard that the manufacturer wants to withdraw this product. But im not sure. https://www.fishersci.se/shop/products/sge-evol-handheld-automated-analytical-syringe-6/12927596

• Michal, I am pleased that the eVOL works so well for you. It is a device I developed with my team at SGE. It is disappointing that it has apparently been discontinued but the same team that developed the eVOL have since developed at ePrep a far more capable automatic syringe which I mentioned above. https://www.digivol.com.au

▪️1. Use 0 5, 1, 2, 4, 5mL and 10mL bulb glass pipette (Emil, Grade A) to take an exact volume...

▪️2. use glass dropper or 200uL Electric pipette and...

▪️Agree with Michał Książkiewicz because Methanol has a low viscosity and vapor pressure

▪️1 and 2 are the cheapest👍 way to carry in the laboratories

www.digivol.com.au

▪️very High analytical cost for using

digiVOL in SPE our laboratory will use the conventional SPE method instead

Time=cost. You have to calculate what it is more efficinet for You.

Regards