Spectrophotometric Determination of Phosphorus in Form of Its Molybdophosphoric Acid Ion Associate with Basic Blue K in Solid Phase of K-KY-2×8 E.E. Kostenko*†, E.N. Butenko†, E.V. Maksimenko†
	* Corresponding authors † National University of Food Technologies. 68 Vladimirskaya St., Kiev, Ukraine, 01601 E-mail: Kostenkoelizaveta@ukr.net
	Methods Objects Chem. Anal., 2015, 10(3), p. 135-142 https://doi.org/10.17721/moca.2015.135-142
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Abstract

The optimum conditions for formation of ion associate (IA) of molybdophosphoric heteropolyacid (GPА) with basic blue K (OCK) in water solution and in solid phase of KY-2×8 were studied. It is determined that optimal conditions for IA formation in the solution are next: C(HNO₃) = 0.4 mol/L, C(Na₂MoO₄) = 9.6∙10^-4 mol/L, Cock = 2∙10^-3%. The Beer's law is obeyed in CP = (0.8-3.2)∙10^-5 mol/L with Cmin(P) = 8.06∙10^-6 mol/L. It is demonstrated that OCK adsorption isotherm on KY-2×8 has L-type with a_max=1.67∙10^-5 mol/g and adsorption constant K(ock) = 2.55∙10⁵ L/mol. Maximum capacity (a_max = 0.32·10^-5 mol/g) of OCK-KY-2×8 towards GPA is reached at the same acidity as it is in solution, but at much lower (9.6∙10–5 mol/L). Adsorption isotherm of GPА is L- type. For phosphorus adsorption from 50–1000 ml solution on 0.3 g of adsorbent, the distribution coefficient is Dmax = 3.83∙104 ml/g. Cmin(P) = 8.06∙10^-7 mol/L. The Beer‘s law is obeyed in interval CP = (0.08-6.45)∙10^-5 mol/L. For determination of 25 μg of phosphorus in solution 103-fold of K, Na, Ca, Mg, Cu, Zn, Co, Ni, Cd, Pl, Al, Tl, In, Ga, Ge, Nb, Ta, V, B ions has do influence. The influence of silicon is diminished by regulation of acidity.

Keywords: solid-phase spectrophotometry, phosphorus, the immobilized dyes, base blue K, food-stuffs

Article language: Rus