University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Email: schalk@unf.edu
Website: @unf

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Joan G. March

Abbrev:
March, J.G.
Other Names:
Address:
Department of Chemistry, University of Balearic Islands, E-07071 Palma de Mallorca, Spain
Phone:
+34-971-172-504
Fax:
+34-971-173-426

Citations 5

"Determination Of Residual Chlorine In Greywater Using O-tolidine"
Talanta 2002 Volume 58, Issue 5 Pages 995-1001
J. G. March, M. Gual and B. M. Simonet

Abstract: The determination of chlorine with o-tolidine in greywater has been studied, and a batch method and a sequential injection method have been proposed. It was found that the reaction of o-tolidine with chlorine was slower in a greywater matrix. Grey water samples must be filtered before analysis, or alternatively, a blank of sample must be measured. The samples are very unstable, and after 2 h of storage in dark conditions at 4°C the chlorine concentration can diminish. The standard addition method, in some samples gave unsatisfactory results as a consequence of matrix effects. It was concluded that samples with a total organic carbon (TOC) higher than 60 mgC L-1 can not be accurately analyzed using these methods. However, samples with a TOC lower than 60 mg C L-1 gave 100±3% recoveries. The linear range of the methods was 0-3.0 and 0-5.0 mg Cl2 L-1, and the limit of quantification 0.2 and 0.5 mg Cl2 L-1, for the batch method and the sequential injection method, respectively. This is the first paper devoted to grey water from the analytical chemistry point of view.
Sequential injection Detector

"Determination Of Phosphate In Urine By Sequential Injection Analysis"
Fresenius J. Anal. Chem. 2001 Volume 369, Issue 1 Pages 96-102
B. M. Simonet, F. Grases, J. G. March

Abstract: Two simple turbidimetric methods for the determination of phosphate in urine are presented and compared. One method is based on the calcium phosphate crystallisation, and the other one on the inhibitory action of phosphate on the calcium carbonate crystallisation. The analytical features of both methods were: linear range 0.2-1.5 g L-1, LOD = 14 mg L-1 and RSD 1.1-2.0% for the calcium phosphate method, linear range = 0.1-1.8 mg L-1, LOD = 0.01 mg L-1 and RSD 0.97-1.90% for the inhibitory method. Urines with high calcium content (greater than or equal to 400 mg L-1) can interfere the method based on the crystallisation of calcium phosphate. This interference was solved using a cation exchange resin as a part of the manifold. Considering the low toxicity of used reagents, these methods can be considered as a contribution to Green Analytical Chemistry.

"Enzymatic Determination Of Pyrophosphate In Urine By Flow Methods"
Anal. Sci. 2003 Volume 19, Issue 7 Pages 1029-1032
Bartolomé M. Simonet, Félix Grases And Juan G. March

Abstract: Two flow methods for the enzymatic determination of pyrophosphate are described that are used to diminish the consumption of reagents. One method is based on the use of an open-close circuit with manual injection using a syringe. The other is a sequential injection method. The analytical features of both methods are: a linear range of 0.4 - 20 mg L-1, an LOD of 0.38 mg L-1, and a CV of 2.0% for the sequential injection method, and a linear range of 0.3 - 15 mg L-1, an LOD of 0.29 mg L-1, and CV of 2.2% for the open-close circuit method. The methods were applied to the determination of pyrophosphate in urine. The pyrophosphate concentration determined in urine samples varied from 1.26 to 6.67 mg L-1.

"O-Tolidine: A New Reagent For A Simple Nephelometric Determination Of Anionic Surfactants"
Anal. Chim. Acta 2005 Volume 539, Issue 1-2 Pages 305-310
J.G. MarchCorresponding Author Contact Information, E-mail The Corresponding Author, M. Gual and A.D. Frontera

Abstract: Simple light scattering methods (batch, flow injection, sequential injection) for the determination of anionic active matter in detergents based on a novel reaction are reported. The methods are based on formation of a solid phase by association of anionic surfactants and protonated o-tolidine. Measurements were carried out with a conventional spectrofluorimeter at 400 nm, and dodecylbenzene sulfonic acid (DBS) was selected as the reference anionic surfactant. Influence of the main parameters affecting the characteristics of the methods was studied by the univariate method. The optimized methods provided linear ranges from 1.6 to 300 mg L-1 DBS with a repeatability within the 1.2-2.6% range. Reaction time for the manual method is 45 s and sampling frequency for FIA and SIA were estimated as 68 and 20 h-1, respectively. The methods were applied to commercial samples and results successfully compared with a volumetric recommended method. The proposed methods are simple, fast and neither require sample preparation nor any organic solvent. © 2005 Elsevier B.V. All rights reserved.

"Kinetic-turbidimetric Determination Of Phytic Acid By Sequential Injection Analysis"
Anal. Chim. Acta 2000 Volume 409, Issue 1-2 Pages 9-16
J. G. March, B. M. Simonet and F. Grases

Abstract: A sequential injection analysis method with kinetic-turbidimetric detection for the determination of phytic acid is described. The method is based on the diminution of the calcium oxalate crystallisation reaction rate in the presence of phytic acid. Such a crystallisation rate has been evaluated from the increase of turbidity with time. A linear calibration graph was obtained from 0.05 to 0.6 mg L-1 phytic acid and the relative standard deviation (n=5) was 2.0% for a standard of 0.25 mg L-1 phytic acid. The method was applied to the determination of phytic acid in food samples (after purification by anion exchange chromatography) and compared with an indirect extraction-spectrophotometric determination based on the hydrolysis of phytic acid and determination of released phosphate.
Phytic acid Food Turbidimetry Kinetic Sequential injection Indirect Method comparison