Fluorometric Determination of Urinary Metanephrine and Normetanephrine

Brunjes, Shannon; Wybenga, Donald R.; Johns, Varner J.

doi:10.1093/clinchem/10.1.1

Cited by 20 publications

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“…The fluorescence yields from normetanephrine and acetyl-normetanephrine by this procedure were, however, poor. Alternative methods of estimation, whereby acetyl-metanephrine and acetyl-normetanephrine were converted to, fluorescent lutine derivatives (Brunjes et al, 1964) proved satisfactory. According to Welsh (1955), acetylation of the catecholamines occurs on the phenolic hydroxyls and the amino nitrogen, the formed ester groups being more readily hydrolysed than the amide linkage.…”

Section: Discussionmentioning

confidence: 99%

“…Blanks prepared from a strip of paper to which nothing was applied and which was chromatographed in parallel with the sample strips were considered satisfactory for the following reasons: (i) The fluorescence from a "'faded " blank (Brunjes, Wybenga & Johns, 1964) prepared from a brain chromatogram eluate known to contain acetyl-normetanephrine was the same as the fluorescence from the corresponding paper blank. (ii) Under normal conditions, adrenaline and metanephrine are not detectable in rat brain.…”

Section: Blanks For Fluorimetric Estimationsmentioning

confidence: 99%

“…Estimation of acetyl-normetanephrine An adaptation of the method of Brunjes et al (1964) was used. 1P00 ml.…”

Section: Estimation Of Acetylated Derivatives Of Adrenaline Noradrenmentioning

confidence: 99%

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A method for the estimation of the catecholamines and their metabolites in brain tissue

Crawford

Yates

1970

British J Pharmacology

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A method is described whereby the catecholamines, their precursors and metabolites may be estimated in the same brain sample. The method, outlined below, was rigorously tested in pure solution before being applied to the estimation of the catechol and methoxyamines in extracts of rat brain. (i) The brain tissue was homogenized in perchloric acid and the perchloric acid removed as its insoluble potassium salt. (ii) The acid metabolites of the amines were extracted from the acidified extract into ethyl acetate. (iii) After extraction with ethyl acetate, the aqueous extract was treated with acetic anhydride and sodium hydrogen carbonate and the acetylated derivatives of the amines extracted into dichloromethane. (iv) The aqueous solution remaining after extraction with dichloromethane contains the acetylated amino‐acids. Acetyl‐dopa could be extracted into dichloromethane only after acidification of this aqueous solution. The acetyl‐dopa in this dichloromethane extract could be estimated fluorimetrically. (v) The dichloromethane extract containing the acetylated amines was chromatographed on paper in the organic phase of a mixture of toluene: ethyl acetate: methanol: water, 10: 1: 5: 5. (vi) The acetylated amines were eluted and estimated fluorimetrically. A new method was developed for the estimation of 3‐methoxytyramine and its acetylated derivative. The reproducibility of the method was demonstrated by the consistent estimates obtained for the concentrations of noradrenaline, dopamine and 3‐methoxytyramine in whole rat brain. Adrenaline and metanephrine were not detected. The concentration of normetanephrine in rat brain was at the limit of detection of the method. Although the estimation for the levels of endogenous amines in whole rat brain were consistent, the recoveries of exogenous amines taken through the procedure were low and very variable. Control experiments demonstrated that the exogenous amines were lost at the perchloric acid extraction stage of the procedure.

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Section: Discussionmentioning

confidence: 99%

Section: Blanks For Fluorimetric Estimationsmentioning

confidence: 99%

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A method for the estimation of the catecholamines and their metabolites in brain tissue

Crawford

Yates

1970

British J Pharmacology

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“…Metanephrine and normetanephrine (the 3-methoxy derivatives which are metabolites of the parent substances) were reported not to interfere in a trihydroxyindole fluorometric procedure for the latter (280). The two types of substances can be separated by adsorp- tion on a cation exchange resin (71,423); the catecholamine can be eluted selectively with boric acid, followed by elution of the methoxy derivatives with dilute sulfuric acid (281) and fluorometric determination of all four compounds. Studies have been made of possible interferences due to the presence of dopa (3,4-dihydroxyphenylalnine) (280, 302), 6-methyldopa (375), and dopamine (139).…”

Section: Organic and Biologicalmentioning

confidence: 99%

Fluorometric Analysis

White¹,

Weissler²

1966

Anal. Chem.

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This review coversthe two-year period from approximately December 1963 {465) to December 1965. Bozhevol'nov {56) has published a review on the luminescence of inorganic substances with 172 references and on fluorescence analysis for the determination of inorganic trace impurities in high purity substances {57).Shcherbov {388) has published a 259page book with 681 references on the use of fluorometry in the chemical analysis of mineral raw materials. Topics included are: general considerations, basic laws, apparatus, reagents

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“…The stability of the fluorophores appears to depend on the pH of the final solution. If this is near neutrality the fluorescence is stable for 1 h (Smith & Weil-Malherbe, 1962;Weil-Malherbe & Smith, 1966), but if it becomes unduly alkaline the fluorescence becomes unstable (Brunjes, Wybenga & Johns, 1964; Weil-Malherbe & Smith, 1966).…”

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confidence: 99%

A study of the formation of fluorescent derivatives of 4-hydroxyphenethylamine (tyramine), 4-hydroxy-3-methoxyphenethylamine (3-methoxytyramine) and related compounds by reaction with hydrazine in the presence of nitrous acid

Scott¹

1971

Biochemical Journal

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A reaction is described that allows the preparation of fluorescent derivatives of a group of related compounds with the basic 4-hydroxyphenethylamine structure. Examination of the reaction shows that it takes place in two stages, which can be considered separately. (1) Reaction of hydrazine with nitrous acid: this is instantaneous at room temperature and involves the reaction of 1 mol of hydrazine with 2 mol of nitrous acid. (2) Reaction with 4-hydroxyphenethylamine compounds: this occurs slowly at room temperature but the rate of reaction is significantly increased at higher temperatures. Ammonium sulphamate is added to remove excess of nitrous acid, found to be detrimental to the reaction. Examination of reagent concentrations necessary for maximum fluoresence yield demonstrated the need for a 40-fold molar excess of the reagent formed in the first stage. The derivatives fluoresce in alkaline solution, the fluorescence of derivatives of 4-hydroxy compounds being stable for over 1h at room temperature, those of 4-hydroxy-3-methoxy compounds being slightly less stable. The derivatives were distinguishable from their parent compounds by t.l.c.

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Fluorometric Determination of Urinary Metanephrine and Normetanephrine

Cited by 20 publications

References 0 publications

A method for the estimation of the catecholamines and their metabolites in brain tissue

A method for the estimation of the catecholamines and their metabolites in brain tissue

Fluorometric Analysis

A study of the formation of fluorescent derivatives of 4-hydroxyphenethylamine (tyramine), 4-hydroxy-3-methoxyphenethylamine (3-methoxytyramine) and related compounds by reaction with hydrazine in the presence of nitrous acid

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