Ambient Electrosynthesis of Ammonia: Electrode Porosity and Composition Engineering

A method for the estimation of urea in milk using ammonia electrode is described. Urea is first degraded by urease enzyme into ammonium ion and carbon dioxide at neutral pH. The ammonium ion is then converted into ammonia at alkaline pH. A linear inverse relationship was observed between logarithmic concentration of ammonia or urea and electrode response. Repeatability, expressed as a coefficient of variation, was 1·77% at a level of 8·92 mm-urea in milk. The method was validated in milk samples spiked with between 2×10−3 and 10×10−3 m-urea and recovery of added urea was quantitative. Whereas, preservative sodium azide at 0·5 g/l or 2 g/l level did not affect results, lower values of urea concentration in presence of Bronopol at 0·5 g/l were observed. Urea levels in milk samples estimated by this method were comparable to standard enzymatic method. The method is simple, fast and is not prone to interference from other milk constituents.

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Urea analysis with the ammonia electrode.

Journal of Applied Physiology ◽

10.1152/jappl.1974.37.5.756 ◽

1974 ◽

Vol 37 (5) ◽

pp. 756-757 ◽

Cited By ~ 4

Author(s):

J L Renfro ◽

Y Patel

Keyword(s):

Ammonia Electrode

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Pore growth onn-InP in liquid ammonia: electrode potential and morphology evolution

physica status solidi (c) ◽

10.1002/pssc.200779427 ◽

2008 ◽

Vol 5 (11) ◽

pp. 3484-3487 ◽

Cited By ~ 4

Author(s):

A. Eb ◽

A.-M. Gonçalves ◽

L. Santinacci ◽

C. Mathieu ◽

A. Etcheberry

Keyword(s):

Electrode Potential ◽

Liquid Ammonia ◽

Morphology Evolution ◽

Pore Growth ◽

Ammonia Electrode

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Use of ammonia electrode for total nitrogen determination in plants

Communications in Soil Science and Plant Analysis ◽

10.1080/00103627609366658 ◽

1976 ◽

Vol 7 (5) ◽

pp. 477-481 ◽

Cited By ~ 24

Author(s):

E. F. Eastin

Keyword(s):

Total Nitrogen ◽

Nitrogen Determination ◽

Ammonia Electrode

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Determination of Nitrate and Exchangeable Ammonium in Soil Extracts by an Ammonia Electrode

Soil Science Society of America Journal ◽

10.2136/sssaj1980.03615995004400050013x ◽

1980 ◽

Vol 44 (5) ◽

pp. 943-947 ◽

Cited By ~ 13

Author(s):

R. S. Siegel

Keyword(s):

Soil Extracts ◽

Ammonia Electrode

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Use of an ammonia electrode to study bacterial deamination of amino acids with special reference tod-asparagine breakdown by campylobacters

Journal of Hygiene ◽

10.1017/s0022172400064706 ◽

1984 ◽

Vol 93 (2) ◽

pp. 189-196 ◽

Cited By ~ 5

Author(s):

M. A. Karmali ◽

A. Williams ◽

P. C. Fleming ◽

C. Krishnan ◽

M. M. Wood

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Special Reference ◽

Developmental Stage ◽

Campylobacter Jejuni ◽

Practical Approach ◽

Theoretical Possibility ◽

Asparaginase Activity ◽

Bacterial Groups ◽

Ammonia Electrode

SummaryA method using an ammonia electrode is being developed for investigating the deamination of amino acids and amides by bacteria. Application of this method toCampylobacter jejuniandC. colihas led to the demonstration ofd-asparaginase activity in some strains. This has allowed the subdivision of both species intod-asparaginase-positive and -negative biotypes. Even though the method is in the developmental stage, it was found to be generally reproducible and easy to perform. Areas for further improving the procedure have been identified. The ammonia electrode offers the theoretical possibility of investigating the breakdown of any amino acid by bacteria. It thus opens up a new and practical approach for separating species and strains, particularly in those bacterial groups that are difficult to subdivide by conventional means.

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