Die Quantitative Organische Mikroanalyse

Pregl, Fritz; Roth, Hubert

doi:10.1007/978-3-662-02170-5

Cited by 95 publications

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“…Si evita cosl quella zona di aeidit~ alla quale si avrebbe anche la riduzione deli'acido molibdico non combinato con l'acido fosforico. 1 Le concentrazioni dei vari reattivi usati, sopratutto del solfito di sodio, devono essere tall da ottenere un pH finale osciliante fra 2,5 e 2,9 (determinato con l'elettrodo ad antimonio), a cui la stabilit~ del colore massima. Per il procedimento pratico sara detto in seguito.…”

Section: B) Riduzione Del Complesso ~Os]omolibdieo Con Svil~ppo Del Cunclassified

I fondamenti chimici e chimico-fisici della microdeterminazione colorimetrica dell'acido fosforico mediante l'azzurro di molibdeno

Zambotti

1939

Mikrochim Acta

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I f o n d a m e n t i chimici e ehimieo-fisiei della m i e r o d e t e r m i n a z i o n e c o l o r i m e t r i c a d e l r a c i d o fosforieo m e d i a n t e r a z z u r r o di molibdeno.* I. Metodi di dosagglo delrione foslorieo. Di Y. Zambotti, (Eingelang~ am 8. Augus~ 1938.) Numerosi sono i metodi di determinazione dell'ione fosforico in materiale biologico elaborati nell'ultimo ventennio. Li possiamo suddividere in quattro gruppi: metodi gravimetriei, vohmetriei, nefelometrici e colorimetrici.A. Metodi g r a v i m e t r i c i . II metodo fondamentale ~ quello originario di Pre~l.Lieb(1), che consiste essenziahnente nella precipitazione dell'lone fosforico come complesso fosfomolibdico e ne] pesare quest'ultimo, dopo opportuno tra~ta-mento. Tutte le successive modificazioni riguardano sopratutto il trattamento del materiale, sul quale si esegue la determinazione.Kuhn (2) ha potuto determinate con esso quantit~ di tosforo fino a rag. 0,03. Holtz (3) ha modificato il procedlmento in modo da renderlo pih sensibile. Embden (4) precipita l'ione fosforico sotto forma di un complesso di fosfomolibdato e stricnina. Con quest'ultimo metodo Myrbdcb (5) ha dosato quantit/~ di fosforo variabili da 0,2 a 0,05 rag. Poster. nacb (6) scioglie il precipitato di fosfomolibdato in ammoniaca e 1o ripreeipita sotto iorma di sale di bario per aumentarne il peso, mediante trattamento con cloruro di bario.Anzicch~ sotto forma di iosiomolibdato ammonico l'aeido fosforico da qualche Autore fu dosato gravimetricamente sotto forma di fosfato ammonico magnesiaco senza per5 aleun vantaggio.I metodi gravimetrici ebbero scarsa applicazione in bioehimica, perch~ presentano varie cause d'errore dovute sopratutto alla precipitazione e ai successivi lavaggi de] precipitato. * Diese Arbeit wurde noch yon der friiheren Schriftleitung der ,,Mikrochemie" redigiert.Mlkrochemie, Bd. XXVI/1 2. 8

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Section: B) Riduzione Del Complesso ~Os]omolibdieo Con Svil~ppo Del Cunclassified

I fondamenti chimici e chimico-fisici della microdeterminazione colorimetrica dell'acido fosforico mediante l'azzurro di molibdeno

Zambotti

1939

Mikrochim Acta

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“…Various groups of workers (RICH and HAMILTON, 1940;MACHELLA and MAGUIRE, 1941; SPELLBURG, KEETON and GINSBERG, 1942; MACDONALD, 1955; and MACDONALD and THOMAS, 1956) have employed dietary methods to induce a fibrous tissue reaction of a similar nature in the liver of animals. In view of the widespread belief that the low protein content of the diet is the major aetiological factor in the production of kwashiorkor, and that protein deficiency, inter alia, is also a feature in children who show the clinical picture of marasmus only, studies of the protein metabolism should prove to be of interest.…”

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confidence: 96%

“…The volume, total nitrogen, sodium and potassium content were determined. Total nitrogen was measured by a modified Pregl microKjeldahl technique (PREGL, 1923), and sodium and potassium levels were determined by means of an Eel photoelectric flame photometer.Paper chromatography was employed as a means of studying the urinary amino acids. 8 ml.…”

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confidence: 99%

Urinary Amino Acid Excretion in an Experimental Nutritional Hepatic Fibrosis

Griffiths

1962

Journal of Tropical Pediatrics

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The changes in the livers of West African children suffering from kwashiorkor have been described in detail by WALTERS and WATERLOW (1954). Various groups of workers (RICH and HAMILTON, 1940;MACHELLA and MAGUIRE, 1941; SPELLBURG, KEETON and GINSBERG, 1942; MACDONALD, 1955; and MACDONALD and THOMAS, 1956) have employed dietary methods to induce a fibrous tissue reaction of a similar nature in the liver of animals. In view of the widespread belief that the low protein content of the diet is the major aetiological factor in the production of kwashiorkor, and that protein deficiency, inter alia, is also a feature in children who show the clinical picture of marasmus only, studies of the protein metabolism should prove to be of interest. In their study of an experimental nutritional hepatic fibrosis presenting many features comparable to kwashiorkor, MAC-DONALD and THOMAS (1956) found the same hepatic changes in rabbits whether they had been fed on a diet either high or low in content of protein provided there was an abundance of readily-available carbohydrate. The present work was undertaken to find out whether there was evidence of disorder of amino acid metabolism in response to these two diets and to what extent any changes in urinary amino acid output could be correlated with the hepatic changes. METHODSEight young adult rabbits'of similar weight but mixed breed were used in these experiments. The animals were divided into two groups, and studies were carried out initially with all the animals on a normal green food diet for a period of one to five months. Then one group was placed on a low protein diet while the other group received a high protein diet. Food and water were supplied freely and the quantity of food eaten was measured daily. Each animal was weighed weekly. Twenty-four hour collections of urine were made from each animal at fourteen day intervals, the animals being kept in metabolic cages. The volume, total nitrogen, sodium and potassium content were determined. Total nitrogen was measured by a modified Pregl microKjeldahl technique (PREGL, 1923), and sodium and potassium levels were determined by means of an Eel photoelectric flame photometer.Paper chromatography was employed as a means of studying the urinary amino acids. 8 ml. of the 24 hour urine was desalted by means of an ion-exchange resin (Zeo Karb. 225 H) contained in columns. The eluate from the columns was evaporated under reduced pressure and the amino acid residue was made up to 1 ml. with distilled water. Some of this concentrate was oxidized (DENT, 1952) and 20 [»l. of the non-oxidised concentrate and the equivalent of the oxidised concentrate were applied to 20 cm. square Whatman 3 MM papers 2 cm. from one corner. After an initial overnight run in a butanol-acetic acid mixture, a second run at right angles to the first was carried out in a phenol-ammonia mixture the following night. The papers were dried and the location of the amino acids was achieved by dipping the papers in 0.2 per cent, ninhydrin in acetone. The spots which ...

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“…It is the purpose of this paper to present data concerning the use of potassium sulfate as one of the reagents in the Parnas-Wagner (7) modification of the Pregl (8,9) modification of the Kjeldahl method. The Pregl-Parnas-Wagner modification is one of the most commonly used for the determination of nitrogen in biologicals, and the details usually followed are those given in the books of Pregl (8,9) or of Niederl and Niederl (6).…”

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confidence: 99%

“…The Pregl-Parnas-Wagner modification is one of the most commonly used for the determination of nitrogen in biologicals, and the details usually followed are those given in the books of Pregl (8,9) or of Niederl and Niederl (6). The descriptions in these texts, particularly with respect to the amount of potassium sulfate to be used, is not at all clear.…”

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confidence: 99%

Micro-Kjeldahl Method for Biologicals

Jacobs

1951

Journal of the American Pharmaceutical Association (Scientific

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Die Quantitative Organische Mikroanalyse

Cited by 95 publications

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I fondamenti chimici e chimico-fisici della microdeterminazione colorimetrica dell'acido fosforico mediante l'azzurro di molibdeno

I fondamenti chimici e chimico-fisici della microdeterminazione colorimetrica dell'acido fosforico mediante l'azzurro di molibdeno

Urinary Amino Acid Excretion in an Experimental Nutritional Hepatic Fibrosis

Micro-Kjeldahl Method for Biologicals

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