In addition, the temperature can influence the solubility of certain reagents. In aqueous solutions, the solubility of many compounds tends to increase with temperature, which may facilitate the availability of copper ions to react with the components of the yerba mate extract . Noubigh et al. studied the effects of temperature on the solubility of some phenolic compounds in water and found that solubility increases with increasing temperature. An increase of 25 ºC caused a 2.4fold increase in the solubility of vanillin .