Spectrophotometric Determination of Calcium with Chlorophosphonazo III in the Presence of Yttrium and Aluminum O.V. Gаyduk*
	* Corresponding authors State Scientific Institution “Institute for Single Crystals” of NAS of Ukraine, Nauky ave. 60, Kharkiv, 61001, Ukraine, *e-mail: ogayduk@isc.kh.ua
	Methods Objects Chem. Anal., 2017, 12(3), p. 135-139 https://doi.org/10.17721/moca.2017.135-139
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Abstract

The conditions for the complexation of calcium, yttrium and aluminum with chlorophosphonazo III and EDTA were studied for the purpose of developing a method for Ca determination in the presence of predominant amounts of Y and Al. EDTA was used as the masking agent. Optimal conditions for masking of yttrium and aluminum and for calcium determination were determined. It has been experimentally established that a 15-fold excess of EDTA is sufficient to complete masking of Al(III), and no less than 65-fold excess EDTA is necessary for the masking of Y(III) at an optimum pH of 3.05–3.25. The sensitivity of the calcium determination in the presence of a more than 100- fold molar excess of yttrium and aluminum is 0.08 μg/ml. The concentration of Y(III) and Al(III) ions in the analyzed solution should not exceed 5∙10-4 mol/l. The relative standard deviation at the calcium determination in Cr,Ca-doped yttrium aluminum garnet ceramic does not exceed 0.1.

Keywords: spectrophotometry, calcium, chlorophosphonazo III, yttrium aluminum garnet

Article language: Rus