Product codeM011 Murexide
Chemical namePurpuric acid, ammonium salt
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Product Description of Murexide and MX
MX is a 1:250 mixture of Murexide and potassium sulfate. Murexide is a metal indicator for Ca, Co, Cu, Ni, Th, and rare earth metals; it is also a colorimetric reagent for calcium and rare earth metals. Murexide is slightly soluble in water, alcohol, and ether. Murexide is unstable in aqueous solution. Its proton dissociation constants are reported to be pKa1=0, pKa2=9.2 and pKa3=10.5. The solution is yellow in strong acidic conditions, reddish-purple in weak acidic conditions, and bluepurple in alkaline conditions. Detection conditions for calcium are pH 11.3, maximum wavelength 506 nm and detection range 0.2-1.2 ppm.
1) H. Gordon and G. Norwitz, "Spectrophotometric Determination of Calcium in Zirconium Powder by Use of Murexide", Talanta, 1972, 19, 7.
2) K. S. Balaji, S. D. Kumar and P. Gupta-Bhaya, "Stability Constants of Calcium and Lanthanide Ions with Murexide", Anal. Chem., 1978, 50, 1972.
Handling and storage condition
|Appearance：||Reddish to dark reddish purple powder|
|Solubility in water：||To pass test (clear, reddish purple)|
|Absorbance：||≧ 0.200 (around 525 nm)|
|Sensitivity：||To pass test|
|Sulfated ash：||≦ 0.20 %|