THE ISOLATION OF CALCIUM OXALATE FROM FRESH SPINACH**
Oxalic acid is a highly soluble and naturally occurring diacid found in a variety of vegetables including spinach, rhubarb and parsley. The oxalate anion, however, forms insoluble salts with metal cations, such as magnesium and calcium, (Ksp for Calcium Oxalate = 2.3 x 10-9). These insoluble salts are a significant component of most kidney stones. The focus of our investigation is the isolation of calcium oxalate from fresh spinach. After shredding spinach in a blender and centrifuging the resulting pulp, treatment with calcium hydroxide resulted in the formation of calcium oxalate. A laboratory experiment for general chemistry students incorporating the principles of natural product isolation, acid-base chemistry and solubility is proposed based on the results of this investigation.
Falk*, Shannon A. and Cooper, Jeremy T. Ph. D.
"THE ISOLATION OF CALCIUM OXALATE FROM FRESH SPINACH**,"
Georgia Journal of Science, Vol. 77, No. 1, Article 25.
Available at: https://digitalcommons.gaacademy.org/gjs/vol77/iss1/25