[Archilander]

I am having problems making a 20g/L azo-potato-galactan(pouder) suspention using a 100mM citrate buffer pH 4,5.

My problem is that the galactan lumps togeather and makes it imposseble to pipette into my assay as the lumps clots the pipette.

Does anyone have any experience with this or any tips?

[Furanone]

Have your 100 mM citrate buffer prepared in a glass beaker with minimum double the size empty space, then place a propeller-style high-shear mixer into buffer and turn on (I usually like 1500 rpm). Have your galactan powder weighed out in a plastic weighing dish, and then by clasping opposite corners of the weighing dish to fold it up, slowly sprinkle out the galactan powder into the quickly mixing vortex over a period of about 30 seconds to 1 minute. This should give you a good dispersion. If this does not do the trick, then take dispersed and heat in water bath and heat until dissolved. Place back in high shear mixer as needed. This is how I commonly dissolve tough-to-dissolve, super high MW hydrocolloids in water such as carrageenan, xanthan gum, guar gum, etc.

Examples of the mixers I commonly use:
https://www.google.ca/search?q=IKA+high+shear+propeller+mixer&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiwnqvep5bKAhWIOxoKHa75AAUQ_AUIBygB&biw=1920&bih=941#imgrc=_

[Archilander]

Thanks a lot for the tip,

Didn't have access to a propeller-style high-shear mixer so I used a normal heated magnetic stirrer putting 1/3 of the galactan in a little at a time then placed it in a ultrasound bath to disperse tiny lumps, I ended doing this 3 times, quite tedious but it worked.