Urine ferric chloride

The histidinemic urine is sometimes only weakly positive or negative on ferric chloride testing, which reflects either the instability of imidazole-pyruvic acid, the relation of its excretion to protein intake, immaturity of histidine transaminase, or a combination of these factors. Even after histidine loading, histidinemic neonates excrete much smaller quantities of imi-dazolepyruvic acid than do older children. In patients with urocanase deficiency, the levels of blood histidine and urine imidazolepyruvic acid are normal or slightly elevated. Therefore, it is necessary to do a quantitative analysis of blood histidine and urine ferric chloride test in order to overlook the patients with this condition. 

As has already been pointed out, the determination of salicylic acid is intricately interwoven with that of aspirin itself. There is the convenient color reaction with ferric chloride which was already used by Dreser1 to determine free salicylic acid in his own urine after the ingestion of aspirin. However, this reaction is not too specific and considerable work has gone in the development of interference free methods. 

Obermayer s reagent chem A 0.4% solution of ferric chloride in concentrated hydrochloric acid used to test for indican in urine, with a pale-blue or deep-violet color indicating positive. o-b3r,mT-3rz re,a- 3nt n-octadecane orgchem CigHjg Colorless liquid boiling at 318°C soluble in alcohol, acetone, ether, and petroleum, insoluble in water used as a solvent and chemical intermediate. en, ak-t3 de,kan ... 

Salicylates in the urine interact with urinary ketone determinations by the ferric chloride (Gerhardt) method producing a reddish color. 

Mix together 98 ml of 30% sulphuric acid and 2 ml oi ferric chloride solution, and add 1 ml of this reagent to 1 ml of urine. A pale pink colour deepening to blue indicates ingestion of thioridazine. Odier phenothiazines can give colours, but the test is more sensitive dian FPN reagent towards thioridazine. 

Identification of Salicylic Acid in Horse Urine No statutory limit is prescribed for salicylic acid, but it is normally present in horse urine it is important, therefore, to distinguish between normal concentrations and those arising from medication with aspirin or other salicylates such as topically applied methyl salicylate. Normal urine concentrations rarely exceed 10 LLg/ml, but therapeutic doses of aspirin may give concentrations as much as 500 times greater. Addition of 1 ml of freshly prepared ferric chloride solution to 5 ml of urine will give a detectable violet colour when the concentration of salicylic acid exceeds about 100 ig/ml. A positive result should be followed... 

A useful qualitative screening test for salicylic acid is performed by adding a few drops of glacial acetic acid or 0.1N hydrochloric acid to 1 ml of urine, followed by 3 drops of 10% ferric chloride solution. A burgundy red color appears and persists if salicylic acid is present (color may turn reddish brown in the presence of phenothiazines). A serum salicylate level can be obtained in most laboratories. Commerically available test strips may be used with urine as well as serum or plasma to determine the presence of salicylic acid. These tests react only with salicylic acid and therefore do not work on stomach contents or pills, but any salicylate is hydrolyzed in the body to salicylic acid and would be present as such in blood or urine (15). 

None of the commonly used methods for the detection and determination of ketone bodies in serum or urine reacts with ah three ketone bodies. Gerhardt s ferric chloride test reacts with acetoacetate only. Tests using nitroprusside are at least 10 times more sensitive to acetoacetate than to acetone, and give no reaction at all with P hydroxybutyrate. 

Nencki and Sieber (634) in 1882 described a beautiful red color obtained on adding concentrated hydrochloric acid to certain pathological urines. Much confusion exists in the older literature between this Nencki-Sieber reaction, the Salkowski reaction (417, 745) (a red color with hydrochloric acid and dilute ferric chloride), and the urorosein reaction (a red color with hydrochloric acid and nitrite), but the same chromogen is probably mainly... 

M20. Meulemans, O., The ferric chloride test for phenylpyruvic add in urine. Clin. Chim. Acta 6, 152 (1960). 

Several methods have been reported for concentrating lead, cobalt, and nickel in blood, urine, brines, and water prior to final determination by atomic absorption. Sprague and Slavin (6) described a procedure for determining these elements plus copper, cadmium, iron, and manganese in concentrated potassium chloride solutions. The metals were chelated with ammonium pyrrolidine dithiocarbamate (APDC) and extracted with methyl isobutyl ketone (MIBK). It was reported that the optimum pH for the extraction was approximately 2.8. Berman (J) described a similar chelation-extraction procedure for determining lead in urine and blood. Burrell (2) developed a procedure for determining cobalt and nickel in natural waters by atomic absorption in which both metals are first coprecipitated with ferric chloride from ten liters of water. The separated precipitate is subsequently dissolved and made up to 100 ml. volume with hydrochloric acid and water so that the final pH of the solution is 2.5. The nickel and cobalt are then chelated with APDC and extracted with three 10 ml. volumes of MIBK. Three extractions are necessary to achieve complete recovery of the chelated cations. A detection limit of 0.3 fig. of nickel per liter and 0.15 fig. of cobalt per liter was found. 

In 1957, Willard Centerwall developed the diaper test in which elevation of phenylalanine was detected in the urine of affected individuals with PKU by applying a ferric chloride solution... 

The accumulating metabolite is metabolized through alternative pathways, mainly the transaminase reaction. Consequently, imidazole pyruvic acid accumulates in the urine. The imidazole pyruvic, like phenylpyruvic, acid reacts with ferric chloride to yield a blue compound. As a result, the diaper test does not distinguish between phenylketonuria and histidinemia. Yet the diagnosis is of considerable importance because histidinemia is a much more benign disease. Furthermore, histidinemia is not alleviated by withdrawal of phenylalanine from the diet. 

Table A,3, Ferric chloride test (urine). This test is used for detection of oxo-acids, and is useful for detection of PKU. Besides phenylpyruvic acid many other compounds react with ferric chloride by forming different color complexes ...

Bilirubin in urine can be detected by a diazotization reaction (e.g. the Ictotest marketed by Ames) or by its reaction with ferric chloride (Fouchet s test). 

A test for the detection of bilirubin in urine. It is based on the oxidation of bilirubin, by ferric chloride, to produce biliverdin, which can be seen as a green coloration. Various drugs, e.g. chlorpromazine, can interfere by producing a purple colour. 

A test for the detection of excess indican in urine which consists of adding ferric chloride in acid solution, and chloroform to the sample. A blue colour in the chloroform layer indicates in-dicanuria. 

Phenylpyruvic acid may be detected in the urine by Phenistix or by ferric chloride. 

Phenols and cresols or their metabolites may be detected in urine. Mixing 10 mi of urine with 1 mi of 20% ferric chloride will result in a purple color If phenols are present... 

Benzidine methods make use of the very low solubility of benzidine sulfate which can be isolated and titrated as an add as in the method of Rosenheim and Drummond (79), or determined by means of a color reaction such as that with hydrt en peroxide and ferric chloride (91), or sodium fi-naphthoquinone-4-sulfonate(59),orbydiazotizationandcoupling(33,55,72). The colorimetric methods are claimed to be very sensitive. The benzidine method provides a rapid method for estimating ethereal sulfate but since, like the Folin (43) method, it is a difference method it becomes less reliable as the inorganic. ethereal sulfate ratio increases. The precipitation of benzidine sulfate by the original method, especially from hydrolyzed urines, may occasionally be capricious, even to the extent that less benzidine sulfate is precipitated from hydrolyzed urine than from unhydrolyzed urine. This difficulty can be largely overcome by preliminary removal of phosphates and precipitation under conditions recommended by Fiske (42). Under experimental conditions dietary control may serve to ensure that the excretion of phosphate is so low as not to interfere with precipitation of benzidine sulfate (e. g.. Maw (63)). 

Iron Test for Acetoacetic Acid.— Add dilute (1 per cent.) ferric chloride drop by drop to 5 ml. of urine until the buff-coloured precipitate of ferric phosphate, which is given by all specimens of urine, ceases to form. Further addition of the ferric chloride now produces a brown-purple colour if the urine contains more than 0-07 per cent, acetoacetic acid. Urines after administration of salicylates, aspirin, and related drugs, give a violet colour on addition of ferric chloride, which may be mistaken for an acetoacetic acid reaction. 

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