The determination of urea in soil extracts and related samples—a review

Soil Research ◽  
2004 ◽  
Vol 42 (7) ◽  
pp. 709 ◽  
Author(s):  
David F. Lambert ◽  
John E. Sherwood ◽  
Paul S. Francis
Keyword(s):  
Enzymatic Hydrolysis ◽  
Flow Injection Analysis ◽  
Acidic Solution ◽  
Clinical Applications ◽  
Urease Inhibitors ◽  
Viable Option ◽  
Soil Extracts ◽  
Diacetyl Monoxime ◽  
Hydrolysis Of

Although the dominant methods for the determination of urea in clinical applications incorporate selective enzymatic hydrolysis of urea, the determination of urea in soil extracts is complicated by the presence of urease inhibitors. The spectrophotometric determination of urea with an acidic solution diacetyl monoxime and semicarbazide is a viable option but traditional manual procedures are time-consuming. New variations on these procedures, based on microplates or flow-injection analysis methodologies, allow a far greater number of samples to be analysed with high precision and sensitivity.

A Potential Systematic Error in Using Lysivane as Inhibitor in the Measurement of Amniotic Fluid Acetylcholinesterase by the Ellman Method

1983 ◽  
Vol 20 (3) ◽  
pp. 159-162 ◽  
Author(s):  
B A Webb ◽  
S J Richardson ◽  
R Garry ◽  
J Atkins
Keyword(s):  
Enzymatic Hydrolysis ◽  
Amniotic Fluid ◽  
Systematic Error ◽  
Neural Tube ◽  
Neural Tube Defects ◽  
Acidic Solution ◽  
Rate Of Increase ◽  
Background Absorption ◽  
Low Levels ◽  
Hydrolysis Of

The measurement of low levels of cholinesterase or acetylcholinesterase by the Ellman method requires correction for a non-enzymatic increase in absorption at 412 mμ that is due both to non-enzymatic hydrolysis of the acetylthiocholine substrate and to modification of the colour reagent. The rate of increase in absorption is dependent on temperature and pH. Addition of an acidic solution of lysivane to the assay solution for selective measurement of amniotic fluid acetylcholinesterase gives rise to a shift in pH; the use of methanol is suggested as an easier method of dissolving the inhibitor and does not affect the pH of the assay, obviating any need to redetermine the background absorption. There is, however, no improvement in ability of the method to predict pregnancies associated with neural-tube defects.

scholarly journals Determination of inhibition in the enzymatic hydrolysis of cellobiose using hybrid neural modeling

2005 ◽  
Vol 22 (1) ◽  
pp. 19-29 ◽  
Author(s):  
F. C. Corazza ◽  
L. P. V. Calsavara ◽  
F. F. Moraes ◽  
G. M. Zanin ◽  
I. Neitzel
Keyword(s):  
Enzymatic Hydrolysis ◽  
Neural Modeling ◽  
Hydrolysis Of

A miniaturized microtiter plate protocol for the determination of selenomethionine in selenized yeast via enzymatic hydrolysis of protein-bound selenium

2011 ◽  
Vol 3 (3) ◽  
pp. 738 ◽  
Author(s):  
Michael Stiboller ◽  
Markus Damm ◽  
Allycia M. Barbera ◽  
Doris Kuehnelt ◽  
Kevin A. Francesconi ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Microtiter Plate ◽  
Hydrolysis Of ◽  
Selenized Yeast

Selecting the right blood glucose monitor for the determination of glucose during the enzymatic hydrolysis of corncob pretreated with different methods

2011 ◽  
Vol 102 (20) ◽  
pp. 9646-9652 ◽  
Author(s):  
Erinc Bahcegul ◽  
Emre Tatli ◽  
Nazife Isik Haykir ◽  
Serpil Apaydin ◽  
Ufuk Bakir
Keyword(s):  
Blood Glucose ◽  
Enzymatic Hydrolysis ◽  
Blood Glucose Monitor ◽  
The Right ◽  
Hydrolysis Of

Sequence Determination of an Antioxidant Peptide Obtained by Enzymatic Hydrolysis of Oyster Crassostrea madrasensis (Preston)

2016 ◽  
Vol 22 (3) ◽  
pp. 421-433 ◽  
Author(s):  
K. K. Asha ◽  
K. R. Remya Kumari ◽  
K. Ashok Kumar ◽  
Niladri S. Chatterjee ◽  
R. Anandan ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Sequence Determination ◽  
Antioxidant Peptide ◽  
Hydrolysis Of
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