By wt% ethanolamine it should be meant: (mass of pure ethanolamine / mass of sol.)·100%. For volumetric measurement, the density of ethanolamine should be considered. You may take it as 1.012 g/cm3 at 25 °C (*). You may also refer to either the label or other technical-commercial information possibly available from the supplier, besides reliable published data. Density is rather close to that of water. That is also the case for a dilute aq. sol.. Hence, sol. density data does not seems to be strictly necessary for volumetric preparing the intended aq. sol. (**). The mentioned purity assay may have been given as a minimum. You may possibly better refer to the batch analysis certificate, if available from the supplier; or titrate either the product or its prepared aq. solution with previously standardized HCl aq.. Solvent is probably to be understood as water, if not otherwise specified. Please note that ethanolamine is hygroscopic, and readly absorbs CO2 from the atmosphere.
(*) valid for product nº E9508 from Sigma-Aldrich (≥98 %).
(**) You may, nevertheless, refer to: R.E. Reitmeier, V. Sivertz, H.V. Tartar, "Some properties of monoethanolamine and its aqueous solutions", J. Am. Chem. Soc., 62(8) 1940, 1943–1944.
Hi Sondos,you want 3%wt,first look what you have 99% wt or vol.then do calculation to find out mass of ethanolamine per ml, then take amount that contains 3 grams add to it solvent that you want (most likely it will be water because already 99% is in water) to make it 100 grams Good luck