The Determination of the Isoelectric Point.

1933 ◽  
Vol 37 (4) ◽  
pp. 417-424 ◽  
Author(s):  
Lyle Vernon Andrews ◽  
D. J. Brown
Keyword(s):  
Isoelectric Point

A novel reagent for spectroscopic determination of Mo(VI)

2012 ◽  
Vol 66 (1) ◽  
Author(s):  
Sülin Taşcıoğlu ◽  
Esra Kakı ◽  
Senay Taşcıoğlu
Keyword(s):  
Gallic Acid ◽  
Spectrophotometric Determination ◽  
Isoelectric Point ◽  
Hexadecyltrimethylammonium Bromide ◽  
Micellar Effects ◽  
Surface Active Agents ◽  
Binary Complexes ◽  
Molecular Charge ◽  
Surface Active

AbstractA new reagent for spectrophotometric determination of Mo(VI) was developed utilizing micellar effects. For this purpose, differences in the ultraviolet and visible spectral properties of Mo(VI), gallic acid, L-serine, and their binary and ternary solutions were studied in the presence and absence of cationic, anionic, and non-ionic surface active agents. L-serine was observed to form binary complexes and a ternary complex with Mo(VI) and gallic acid below its isoelectric point. The maximum Mo(VI) sensitivity was exerted by the Mo(VI) + gallic acid + L-serine + hexadecyltrimethylammonium bromide system at pH of 4.5. This system was proposed for use in the spectrophotometric determination of Mo(VI) as a superior alternative to the Mo(VI) + gallic acid + hexadecyltrimethylammonium bromide system and to most of the instrumental analysis methods referred to in the literature. The mechanism of micellar effects was discussed on the basis of the spectral data obtained above and below the isoelectric point of L-serine and explained in terms of the molecular charge of the substrates and the surfactants.

scholarly journals Photometric determination of aqueous cobalt (II), nickel (II), copper (II) and iron (III) with 1-nitroso-2-naphthol-3,6-disulfonic acid disodium salt in gelatin films

2012 ◽  
Vol 10 (5) ◽  
pp. 1617-1623 ◽  
Author(s):  
Elena Reshetnyak ◽  
Nataliia Ivchenko ◽  
Nataliya Nikitina
Keyword(s):  
Metal Complexes ◽  
Simultaneous Determination ◽  
Isoelectric Point ◽  
Electrostatic Interaction ◽  
Photometric Determination ◽  
Disodium Salt ◽  
Photographic Film ◽  
Disulfonic Acid ◽  
Gelatin Films

AbstractPhotometric determination of aqueous Co(II), Cu(II), Ni(II) and Fe(III) was performed using indicator films prepared by immobilization of 1-nitroso-2-naphthol-3,6-disulfonic acid disodium salt (NRS) into hardened photographic film. Immobilization was based on electrostatic interaction of reagent and metal complexes with the gelatin. The isoelectric point pH of hardened gelatin (4.46±0.04) was evaluated by viscometry. Co(II), Fe(III), Ni(II) form 1:3 complexes with NRS in gelatin at pH 2 and Cu(II) forms 1:2 complexes. Their log β′ values were: Co-6.7, Fe-8.6, Cu-8.0, and Ni-6.4. The absorption maxima were: 370nm for NRS, and 430nm, 470nm, 495nm and 720nm for complexes of Co(II), Ni(II), Cu(II) and Fe(III). An algorithm for their simultaneous determination using the indicator films was developed. The detection limits were: clim(Co2+) = 0.45×10−5 M, clim(Fe3+) = 0.50×10−5 M, clim(Cu2+) = 0.67×10−5 M, clim(Ni2+) = 0.75×10−5 M,; and their sum clim(ΣMn+) = 0.82×10−5 M.

Isoelectric point determination of human and camel β-endorphin, α-endorphin and enkephalins

1982 ◽  
Vol 104 (2) ◽  
pp. 577-582 ◽  
Author(s):  
Angela Santagostino ◽  
Gabriella Giagnoni ◽  
Pietro Fumagalli ◽  
Daniela Pavesi ◽  
Enrica Torretta
Keyword(s):  
Isoelectric Point ◽  
Point Determination

Isoelectric point determination of cardiac troponin I forms present in plasma from patients with myocardial infarction

2007 ◽  
Vol 377 (1-2) ◽  
pp. 243-247 ◽  
Author(s):  
Estelle Peronnet ◽  
Laurence Becquart ◽  
Jérôme Martinez ◽  
Jean-Philippe Charrier ◽  
Colette Jolivet-Reynaud
Keyword(s):  
Myocardial Infarction ◽  
Isoelectric Point ◽  
Cardiac Troponin ◽  
Troponin I ◽  
Cardiac Troponin I ◽  
Point Determination
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