scholarly journals A spectrophotometric method for the direct determination of cysteine in the presence of other naturally occurring amino acids

1967 ◽  
Vol 104 (2) ◽  
pp. 627-633 ◽  
Author(s):  
MK Gaitonde
Keyword(s):  
Amino Acids ◽  
Spectrophotometric Method ◽  
Direct Determination ◽  
Naturally Occurring

Spectrophotometric Method for the Direct Determination of Available Phosphorus in Fertilizers: Use of Dry Ashing to Destroy Citrate

1965 ◽  
Vol 48 (4) ◽  
pp. 859-865
Author(s):  
Wallace S Brammell
Keyword(s):  
Spectrophotometric Method ◽  
Direct Determination ◽  
Available Phosphorus ◽  
Hot Plate ◽  
Erlenmeyer Flask ◽  
White Ash ◽  
Heat Stable ◽  
Dry Ashing ◽  
Acid Reagent

Abstract A simple, rapid spectrophotometry method has been developed for direct determination of available phosphorus in fertilizers. Citrate and other organic materials are destroyed by dry ashing. The combined water and citrate extracts are diluted, a 5 ml aliquot is pipetted into a 25 ml Erlenmeyer flask, and 2 ml of ashing reagent (dilute HNO3, sucrose, and MgO) is added. During evaporation to dryness on a hot plate, nonorthophosphates are hydrolyzed to orthophosphates which react with Mg to form heat-stable compounds. During the subsequent ashing, phosphorus remains in the ortho form. Due to sucrose, the dry residue has a very porous structure and can be converted to a white ash in about 30 minutes in a pre-heated 550°C muffle. Color is developed with vanadomolybdic acid reagent. Absorbance is read on a spectrophotometer at 400 mμ.

Spectrophotometric method for the direct determination of uranium in carbonate solution

1985 ◽  
Vol 86 (3-4) ◽  
pp. 187-193 ◽  
Author(s):  
I. Brčić ◽  
E. Polla ◽  
M. Radošević
Keyword(s):  
Spectrophotometric Method ◽  
Direct Determination ◽  
Carbonate Solution

Direct determination of amino acids in brewery worts produced by different processes by capillary zone electrophoresis

2018 ◽  
Vol 39 (13) ◽  
pp. 1613-1620 ◽  
Author(s):  
Renata Corrêa de Carvalho ◽  
Thiago Rocha dos Santos Mathias ◽  
Annibal Duarte Pereira Netto ◽  
Flávia Ferreira de Carvalho Marques
Keyword(s):  
Amino Acids ◽  
Capillary Zone Electrophoresis ◽  
Direct Determination ◽  
Zone Electrophoresis ◽  
Capillary Zone
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