scholarly journals The spectrophotometric determination of boron in tourmalines

2005 ◽  
Vol 70 (2) ◽  
pp. 255-260 ◽  
Author(s):  
Ljiljana Jaksic

A procedure for the spectrophotometric determination of macro amounts of boron in tourmaline with azomethine H is described. The used tourmaline concentrate was obtained by magnetic separation and heavy-liquids purification of the schorl zone of pegmatite or granite aplite. The samples of tourmaline were decomposed by fusion with anhydrous sodium carbonate and taken up in dilute hydrochloric acid. The interfering effects of iron and aluminium were eliminated by masking with an EDTA - NTA solution. After pH adjustment, the boron was reacted with azomethine H and the absorbance of the obtained coloured complex was measured at 415 nm. The results are compared with those obtained by other procedures. The relative error of the determination was less than 3 %.

2011 ◽  
Vol 8 (1) ◽  
pp. 110-117 ◽  
Author(s):  
Baghdad Science Journal

A simple, accurate and sensitive spectrophotometric method for the determinaion of epinephrine is described . The method is based on the coordination of Pr (III) with epinephrine at pH 6. Absorbance of the resulting orange yellow complex is measured at 482 nm . A graph of absorbance versus concentrations shows that beer 's low is obeyed over the concentration range (1-50)mg.ml-1 of epinephrine with molar absorpitivity of ( 2.180x103 L.mol-1.cm-1 ), a sandell sensitivity of (0.084 mg.cm-2 ), a relative error of (-2.83%) , a corrolation coffecient (r= 0.9989) and recovery % ( 97.03 ± 0.75 ) depending on the concentration.This method is applied to analyse EP in several commercially available pharmaceutical preparations using direct methods .All statistical calculations are implemented via a Minitab software version 11.


1953 ◽  
Vol 25 (12) ◽  
pp. 1807-1809 ◽  
Author(s):  
J. H. Kanzelmeyer ◽  
Harry Freund

2014 ◽  
Vol 675-677 ◽  
pp. 1429-1432
Author(s):  
Xing Xin Chen ◽  
Kui Liu ◽  
Li Fang Kuang ◽  
Hua Long

Determination of lanthanum in the raffinate by spectrophotometry was studied, using tribromoarsenazo as chromogenic reagent. The addition of ascorbic acid can mask the interference of other metal cations in the solution. Under the conditions of ascorbic acid (10g·L-1) 5 mL, hydrochloric acid 0.04 mol·L-1 and tribromoarsenazo (0.5g·L-1) 2 mL, Beer’s law is obeyed in the range of 0-10 μg·(25mL)-1 for lanthanum, with correlation coefficient higher than 0.99. Beer’s law can be applicable for the wavelength range of 580-660 nm. There is no linear relation at too high or too low acidic environment.


1990 ◽  
Vol 55 (7) ◽  
pp. 1686-1690 ◽  
Author(s):  
José Aznarez ◽  
Juan Carlos Vidal ◽  
Cecilia Vaquero

A method for tantalum(V) spectrophotometric determination in a non-aqueous phase is proposed. Tantalum(V) is extracted with N-phenylbenzohydroxamic acid into toluene from a 5M hydrochloric acid solution. The colour is then developed by addition of 4-(2-pyridylazo)-resorcinol (PAR) solution in N,N-dimethylformamide and pyridine to an aliquot of the extracted phase. The Ta(V)-PAR complex gives an absorption maximum at 547 nm with a molar absorptivity of 3.88 ± 0.04 . 104 l mol-1 cm-1. The method has been applied to the selective determination of tantalum in ores with good accuracy and precision.


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