Spectrophotometric Determination of Calcium with 1-(2-Pyridylazo)-2-Napthol Sensitized By Tween 80 Application to Various Samples

International Conference on Materials Engineering and Science

Jamil, Lazgin A.^1 ; Rahim, Sameer A.^1

Department of Chemistry, Faculty of Science, University of Zakho, Kurdistan Region, Iraq^1

关键词: 1-(2-Pyridylazo)-2-naphthol;    Absorbance measurements;    Average recovery;    Concentration ranges;    Conditional stability constants;    Molar absorptivity;    Spectro-photometric method;    Spectrophotometric determination;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/454/1/012089/pdf
DOI  :  10.1088/1757-899X/454/1/012089

来源: IOP

【 摘 要 】

Spectrophotometric method for determination of Ca in aqueous solution using 1-(2-pyridylazo)-2-naphthol (PAN) as colour reagent has been developed. The method was based on the formation of Ca-PAN complex at pH 12 and measuring absorbance at 550nm, with molar absorptivity of 1.70×104 L.mol-1cm-1, average recovery is 101.72 and precision (RSD) is better than ±2.8% indicating that the method is relatively sensitive, accurate and precise. The binary system of Ca(PAN)2 and conditional stability constant of 1.467x1010 L2.mol-2 adherence of Beer's law over concentration range 0.08-2ppm. The method was applied for the determination of Ca in natural water, milk, yogurt, human serum, grip and tomato juice satisfactory. In presence of 1% tween 80 and composite masking agents of pH 11.5 the absorbance measurements were made at 540nm giving molar absorptivity of 2.7×104 L.mol-1 cm-1, average recovery of 101.2 and precision (RSD) better than ±3% indicating that the Ca(PAN)2 system is sensitive, accurate, and precise. In addition it is considered to be simple, rapid and do not need heating or solvent extraction steps, moreover it can be applied successfully for the assay of Ca in various samples over concentration range of 0.0008-0.8ppm.