| phthalein | <chemistry> One of a series of artificial organic dyes made as condensation products of the phenols with phthalic acid, and well represented by phenol phthalein. Their alkaline solutions are fluorescent. Phenol phthalein, a white or yellowish white crystalline substance made from phthalic acid and phenol. Its solution in alkalies is brilliant red, but is decolourized by acids, and as this reaction is exceedingly delicate it is used as an indicator. See: Phthalic. Source: Websters Dictionary (01 Mar 1998) |
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| phthalein dyes | Coloured condensation products of phenols with phthalic anhydride; some are used in dye dilution methods to determine kidney or liver function; others are used as pH indicators in chemistry; phenolphthalein is an effective mild cathartic. (12 Dec 1998) |
| phthalein test | An obsolete test for renal function; after the patient has drunk a glass or two of water, 1 ml of a 0.6% solution of dye is injected hypodermically; the time between this injection and the appearance of a pink tinge in the urine as it falls into an alkaline solution is noted; the amount excreted in each of the next 2 hours is then estimated colourimetrically. Synonym: Geraghty's test, phthalein test, red test, Rowntree and Geraghty test. (05 Mar 2000) |