Methods of test for starch and its derivatives and by-products. Determination of nitrogen conteny by the Kjeldahl method ( spectrophotometric method)

1979 ◽  
Keyword(s):  
Spectrophotometric Method ◽  
Kjeldahl Method ◽  
By Products

Manual Salicylate-Hypochlorite Procedure for Determination of Ammonia in Kjeldahl Digests

1982 ◽  
Vol 65 (5) ◽  
pp. 1076-1079
Author(s):  
Helen E Fukumoto ◽  
George W Chang
Keyword(s):  
Correlation Coefficient ◽  
Spectrophotometric Method ◽  
Coefficient Of Variation ◽  
Precise Timing ◽  
Coefficients Of Variation ◽  
Moderate Volume ◽  
Kjeldahl Method

Abstract The determination of nitrogen in Kjeldahl digests of urine and feces has been simplified by using a manual spectrophotometric method with salicylate and hypochlorite. It neither involves the hazards of the phenol-hypochlorite method, nor requires an automated analyzer. We determined the conditions which minimize the need for precise timing and neutralization of acidic digests and obtained coefficients of variation of about 0.8%. Agreement between the spectrophotometric method and the conventional micro-Kjeldahl method was excellent; a correlation coefficient of 0.9992 and a coefficient of variation of the estimate of 2.1% were obtained. This method is well suited for a laboratory with a moderate volume of samples. We could process at least 200 digests per day, in contrast with the 60 per day which we had previously done by the Kjeldahl distillation and titration.

Spectrophotometric Method for Microdetermination of Nitrogen in Kjeldahl Digest

1989 ◽  
Vol 72 (6) ◽  
pp. 953-956 ◽  
Author(s):  
Muljibhai B Devani ◽  
Chamanlal J Shishoo ◽  
Shailesh A Shah ◽  
Bhanubhai N Suhagia
Keyword(s):  
Standard Deviation ◽  
Nitrogen Content ◽  
Spectrophotometric Method ◽  
Acidic Medium ◽  
Molar Absorptivity ◽  
Nitrogen Compounds ◽  
Relative Standard ◽  
Kjeldahl Method ◽  
Aoac Method

Abstract A new spectrophotometric method for the determination of nitrogen in Kjeldahl digest has been developed. The method is based on the reaction of ammonia with acetylacetone-formaldehyde reagent in aqueous medium to yield yellow 3,5-diacetyl- 1,4-dihydrolutidine with a characteristic absorption maxima at 412 nm. The effect of several experimental variables on the determination of nitrogen was studied. The method was suitable for determination of nitrogen in acidic medium without interference from the usual catalysts employed for the digestion in Kjeldahl method. Lambert-Beer’s law is obeyed in the concentration range of 0.5-6.0 ng nitrogen/mL in the reaction mixture. The molar absorptivity in terms of nitrogen was 1.4 X 103L mol-1 cm-1. The standard deviation and relative standard deviation were ±0.0447 and ±0.896% (n = 10), respectively. The method is simple, rapid, and precise. A variety of carbocyclic and heterocyclic nitrogen compounds have been analyzed for nitrogen content. The results are comparable with those obtained by AOAC method, 47.021.

Extractive Spectrophotometric Method for the Determination of Glibenclamide by Ion-Pair Complex in Pure Form and Pharmaceutical Formulation

2019 ◽  
Vol 9 (o3) ◽  
Author(s):  
RUAA MUAYAD MAHMOOD ◽  
HAMSA MUNAM YASSEN ◽  
SAMAR , NAJWA ISSAC ABDULLA AHMED DARWEESH ◽  
NAJWA ISSAC ABDULLA
Keyword(s):  
Spectrophotometric Method ◽  
Molar Absorptivity ◽  
Ion Pair ◽  
Pharmaceutical Formulation ◽  
Ratio Method ◽  
Colored Complex ◽  
Colored Product ◽  
Method Of Continuous Variation ◽  
Job's Method

Simple, rapid and sensitive extractive spectrophotometric method is presented for the determination of glibenclamide (Glb) based on the formation of ion-pair complex between the Glb and anionic dye, methyl orange (MO) at pH 4. The yellow colored complex formed was quantitatively extracted into dichloromethane and measured at 426 nm. The colored product obeyed Beer’s law in the concentration range of (0.5-40) μg.ml-1. The value of molar absorptivity obtained from Beer’s data was found to be 31122 L.mol-1.cm-1, Sandell’s sensitivity value was calculated to be 0.0159 μg.cm-2, while the limits of detection (LOD) and quantification (LOQ) were found to be 0.1086 and 0.3292 μg.ml-1, respectively. The stoichiometry of the complex created between the Glb and MO was 1:1 as determined via Job’s method of continuous variation and mole ratio method. The method was successfully applied for the analysis of pharmaceutical formulation.

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