Enzymic Determination of Peroxides in Non-aqueous Media

The Analyst ◽  
1997 ◽  
Vol 122 (12) ◽  
pp. 1543-1547 ◽  
Author(s):  
Gerardo Piñeiro Avila ◽  
Miguel de la Guardia
Keyword(s):  
Aqueous Media

Dissociation of imino proton(s) of a highly water-soluble metal-free phthalocyanine and determination of its pKa value in water

2013 ◽  
Vol 17 (06n07) ◽  
pp. 447-453 ◽  
Author(s):  
Hiroaki Isago ◽  
Harumi Fujita
Keyword(s):  
Aqueous Media ◽  
Thermal Reaction ◽  
Water Soluble ◽  
Acid Dissociation ◽  
Acid Dissociation Constant ◽  
Metal Free ◽  
Imino Proton ◽  
Pka Value ◽  
Triton X

Dissociation of imino proton(s) in the cavity of the macrocycle of a highly water-soluble, metal-free phthalocyanine ( H 2( H 4 tsppc ); where H 4 tsppc denotes tetrakis{(2′,6′-dimethyl-4′-sulfonic acid)phenoxy}phthalocyaninate) in ethanolic and aqueous solutions has spectrophotometrically been investigated. The spectral changes associated with reaction with NaOH have been found to involve one-proton transfer process in aqueous media while two-protons process in ethanolic media. The acid-dissociation constant of the first imino proton in water (in the presence of Triton X-100) has been determined to be 12.5 ± 0.2 (as pKa) at 25 °C. The doubly deprotonated species in EtOH has been easily converted to its corresponding cobalt(II) derivative by thermal reaction with anhydrous CoCl 2.

Extraction-atomic-absorption spectrophotometric determination of antimony by generation of its hydride in non-aqueous media

The Analyst ◽  
1984 ◽  
Vol 109 (2) ◽  
pp. 123-125 ◽  
Author(s):  
José Aznárez ◽  
Francisco Palacios ◽  
Maria S. Ortega ◽  
Juan Carlos Vidal
Keyword(s):  
Atomic Absorption ◽  
Spectrophotometric Determination ◽  
Aqueous Media

Two-photon excited fluorescent chemosensor for homogeneous determination of copper(ii) in aqueous media and complicated biological matrix

The Analyst ◽  
2011 ◽  
Vol 136 (10) ◽  
pp. 2139 ◽  
Author(s):  
Lingzhi Liu ◽  
Xiaohu Dong ◽  
Yan Xiao ◽  
Wenlong Lian ◽  
Zhihong Liu
Keyword(s):  
Aqueous Media ◽  
Fluorescent Chemosensor ◽  
Biological Matrix ◽  
Two Photon ◽  
Determination Of Copper

Free-base corroles: determination of deprotonation constants in non-aqueous media

2007 ◽  
Vol 11 (04) ◽  
pp. 269-276 ◽  
Author(s):  
Jing Shen ◽  
Zhongping Ou ◽  
Jianguo Shao ◽  
Michał Gałęzowski ◽  
Daniel T. Gryko ◽  
...  
Keyword(s):  
Equilibrium Constants ◽  
Aqueous Media ◽  
Free Base ◽  
Organic Base ◽  
Experimental Conditions ◽  
Spectral Changes ◽  
Base Analysis ◽  
Uv Visible ◽  
The Given

A series of free-base corroles with different electron-donating or electron-withdrawing substituents were reacted with piperidine, 4-aminopyridine, 2-methylimidazole, 2-aminopyridine or pyridine in PhCN and the UV-visible spectral changes monitored during conversion of ( Cor ) H 3 to [( Cor ) H 2]- as a function of the concentration and strength of the added organic base. Analysis of the UV-visible spectral changes as a function of the added base concentration enabled calculation of equilibrium constants ( logK ) for deprotonation of each corrole under the given experimental conditions. Relationships are examined between the experimentally measured logK values and previously published spectroscopic and structural properties of the compounds.

scholarly journals Automation of flow injection gas diffusion-ion chromatography for the nanomolar determination of methylamines and ammonia in seawater and atmospheric samples

1995 ◽  
Vol 17 (6) ◽  
pp. 205-212 ◽  
Author(s):  
Stuart W. Gibb ◽  
John W. Wood ◽  
R. Fauzi ◽  
C. Mantoura
Keyword(s):  
Ion Chromatography ◽  
Flow Injection ◽  
Aqueous Media ◽  
Control Unit ◽  
Gas Diffusion ◽  
Aqueous Sample ◽  
In Series ◽  
And Performance ◽  
Improved Design

The automation and improved design and performance of Flow Injection Gas Diffusion-Ion Chromatography (FIGD-IC), a novel technique for the simultaneous analysis of trace ammonia (NH3) and methylamines (MAs) in aqueous media, is presented. Automated Flow Injection Gas Diffusion (FIGD) promotes the selective transmembrane diffusion of MAs and NH3from aqueous sample under strongly alkaline (pH > 12, NaOH), chelated (EDTA) conditions into a recycled acidic acceptor stream. The acceptor is then injected onto an ion chromatograph where NH3and the MAs are fully resolved as their cations and detected conductimetrically. A versatile PC interfaced control unit and data capture unit (DCU) are employed in series to direct the selonoid valve switching sequence, IC operation and collection of data. Automation, together with other modifications improved both linearily (R2> 0.99 MAs 0-100 nM, NH30-1000 nM) and precision (<8%) of FIGD-IC at nanomolar concentrations, compared with the manual procedure. The system was successfully applied to the determination of MAs and NH3in seawater and in trapped particulate and gaseous atmospheric samples during an oceanographic research cruise.

Determination of total carbonyl compounds in aqueous media

1993 ◽  
Vol 70 (9) ◽  
pp. 881-884 ◽  
Author(s):  
Natsuko Yukawa ◽  
Hitoshi Takamura ◽  
Teruyoshi Matoba
Keyword(s):  
Carbonyl Compounds ◽  
Aqueous Media ◽  
Total Carbonyl
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