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US 6,599,748 B1Granted
Hardness indicator composition and method of water hardness analysis
AssigneesMiura Co., Ltd., Miura Institute of Research & Development Co., Ltd.
InventorsJunichi Nakajima, Keita Mizogami, Yuuji Ukena
Life of this patent
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Abstract
A hardness indicator composition, and a method of water hardness analysis, capable of measuring hardness even with higher-hardness water without requiring titration by a two-liquid system. The hardness indicator composition is formulated of a metal indicator with a desensitizer added thereto.
Claims4
A hardness indicator composition comprising a metal indicator which contains a dye represented by any one of general formulas (I)-(III):
- wherein R is any one H, OH, NO2, CH3, SO3H and COOH,
- where R is any one of H, OH, NO2, CH3, SO3H and COOH, and
- where R is any one of H, OH, NO2, CH3, SO3H and COOH, and a desensitizer, wherein the desensitizer has a Ca chelate stability constant ≦2.59.
Dependencies are inferred from the claim text.