HNB
Metal Indicator
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Product codeH007 HNB
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CAS No.63451-35-4
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Chemical name2-Hydroxy-1-(2-hydroxy-4-sulfo-1-naphthylazo)-3,6-naphthalenedisulfonic acid, trisodium salt
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MWC20H11N2Na3O11S3=620.48
| Unit size | -- | |
|---|---|---|
| 1 g | Please inquire distributors about price. | |
Description
HNB is a metal indicator for calcium, and a colorimetric reagent for alkaline earth metal ions, rare earth metal ions, and uranium ions. HNB is readily soluble in water and alcohol. Aqueous solution of HNB is blue at pH 7-12, red above pH 13, and pink in the presence of calcium at pH 10. The detection range of alkaline earth metal ions and rare earth metal ions are 1-600 ppm and 1-300 ppm, respectively. The maximum wavelength of the complex is 650 nm. HNB is also used for UO2(II) detection. The proton dissociation constants of HNB are reported to be pKa4=6.44 and pKa5=12.91(μ=0.1, 24ºC).
Chemical Structure
References
1. A. Itoh, et al., Evaluation of 2-Hydroxy-1-(2-Hydroxy-4-Sulpho-1-Naphthylazo)-3-Naphthoic Acid and Hydroxynaphthol Blue as Metallochromic Indicators in the EDTA Titration of Calcium. Analyst. 1970;95:583-589.
2. M. Sugawara, et al., Catalytic Decomposition of the Excess Reagent in the Spectrophotometric Determination of Copper(II) with O,O EDihydroxyazo Compounds. Bull Chem Soc Jpn. 1977;50:3206-3208.
3. M. M. Ferris, et al., Examination of Metallochromic Indicators and Water-soluble Reagents for Metals by Planar Electrophoresis. Analyst. 1986;111:351-354.
Handling and storage condition
| Appearance： | Black purple powder |
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| Solubility in water： | To pass test (clear, red or deep reddish purple) |
| Absorbance： | ≧ 0.600 (around 647 nm) |
| Absorbance (Calcium complex)： | ≧ 0.310 (around 562 nm) |
| Sulfated ash： | ≦ 35.0 % |
| Sensitivity： | To pass test |
| IR spectrum： | Authentic |
| Ambient temperature |
