On lead(II) glycocholate solubility

The solubility of lead(II) glycocholate was studied as a function of glycocholate ion concentration at 25 degrees C and in 0.100, 0.500 and 0.800 mol dm-3 N(CH3)4Cl as a constant ionic medium. For this purpose the total concentration of lead(II) was determined by means of atomic absorption spectrophotometry and polarography measurements in solution equilibrated with solid lead(II) glycocholate at known hydrogen ion concentration. The free concentration of lead(II) and hydrogen ions was determined by measuring the electromotive force(e.m.f.) of galvanic cells involving lead amalgam and glass electrode. The e.m.f. measurements were carried out both in clear solutions before precipitation and in the presence of the precipitate. The results of the solubility and e.m.f. measurements could be explained by assuming the presence of associated species between lead(II) and glycocholate. The solubility product and the association constants were determined for all the ionic medium concentrations.