Direct determination of nitrate in small volumes of natural surface waters using a simple spectrophotometric method

2012 ◽  
Vol 31 (3-4) ◽  
Author(s):  
Laura Bulgariu ◽  
Dumitru Bulgariu
Keyword(s):  
Surface Waters ◽  
Spectrophotometric Method ◽  
Direct Determination ◽  
Natural Surface

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

A Modification of the Spectrophotometric Determination of Carbon Monoxide in Blood Enabling Direct Determination of Per Cent Hemoglobin Saturation

1959 ◽  
Vol 5 (2) ◽  
pp. 127-134 ◽  
Author(s):  
Hans Berninger ◽  
Roger Smith
Keyword(s):  
Carbon Monoxide ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Experimental Error ◽  
Direct Determination ◽  
Hemoglobin Saturation

Abstract A modification of the spectrophotometric method for the determination of carbon monoxide in blood has been presented that enables direct determination of per cent hemoglobin saturation with an overall experimental error of 3 per cent.

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