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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Pavel Mikuska

Abbrev:
Mikuska, P.
Other Names:
Address:
Institute of Analytical Chemistry, Academy of Sciences of the Czech Republic, Brno, Czech Republic
Phone:
+420-532290167
Fax:
+420-541212113

Citations 6

"Flow-injection Chemiluminescence Determination Of Formaldehyde In Water"
Talanta 2007 Volume 71, Issue 2 Pages 900-905
Kamil Motyka, Antonije Onjia, Pavel Mikuška, Corresponding Author Contact Information, E-mail The Corresponding Author and Zbyněk Večeřa

Abstract: A modification of the Trautz-Schorigin reaction into a flow-injection analysis configuration is described. Different approaches were used at the optimization of chemiluminescence determination of formaldehyde in water based on the reaction of formaldehyde, gallic acid and hydrogen peroxide in an alkaline solution. Detection system with a 218 µL chemiluminescence cell was optimized by both a one-variable-at-a-time method, and a modified simplex method. A calibration graph is linear in the concentration range 4 x 10^-8 to 1 x 10^-5 M HCHO. The detection limit of formaldehyde for a signal-to-noise ratio of 3 is 4 x 10^-8 M. The relative standard deviations for 15 repeated measurements of 1 x 10^-6 and 5 x 10^-6 mol L-1 HCHO are 4.32 and 3.33%, respectively. The analysis time is 1.5 min. The method was applied to the determination of formaldehyde in urban rainwater. A comparison of results found by proposed method with those obtained by fluorimetric reference method provided a good agreement. © 2006 Elsevier B.V. All rights reserved.

"Continuous Determination Of Trace Concentrations Of Ammonia In Air"
Chem. Listy 2003 Volume 97, Issue 3 Pages 166-170
M. Dobsik, P. Mikuska, and Z. Vecera

Abstract: A method for continuous determination of trace concentrations of ammonia in ambient air is described. The method is based on ammonia pre-concentration in a wet cylindrical diffusion denuder and subsequent on-line effluent analysis with conductometric detection. The method provides fast, sensitive and selective determination of ambient ammonia. The detection limit of ammonia in air is 100 ppt for flow injection analysis and 20 ppt for continuous analysis of ammonia in denuder effluent.

"Chemiluminescent Flow Determination Of Nitrates In Water"
Chem. Listy 2002 Volume 96, Issue 9 Pages 748-750
Pavel Mikuska and Zbynek Vecera

Abstract: A fast and simple flow-injection method for sensitive automated determination of nitrates in various water samples is described. The method is based on the on-line photolytic conversion of nitrate in a quartz capillary to nitrite, which is determined by a chemiluminescent reaction. The photolytic conversion provides ecological detection of nitrate as compared with nitrate reduction at copperized cadmium. The detection limit is 2 10^-7 M nitrate, the calibration curve is linear to 1 10^-5 mol.l-1. The efficiency of conversion of nitrate to nitrite is 63 %. The method is usable for the simultaneous determination of nitrate and nitrite in water.

"Simultaneous Determination Of Nitrite And Nitrate In Water By Chemiluminescent Flow-injection Analysis"
Anal. Chim. Acta 2003 Volume 495, Issue 1-2 Pages 225-232
Pavel Mikuska and Zbynek Vecera

Abstract: A sensitive and fully automated flow-injection system for the simultaneous determination of nitrite and nitrate in water is described. The method combines online photolytic conversion of nitrate to nitrite and the chemiluminescent detection of nitrite. Nitrite initially present in the sample is directly determined after oxidation to peroxynitrous acid by the chemiluminescent reaction with luminol. Nitrate in another portion of sample is photolytically reduced to nitrite by absorption of UV light at quartz capillaries and the sum of original and reduced nitrite is detected in the parallel detection system via the same way. Nitrate content is determined from the difference. The detection limit of nitrite (S/N=3) is 2 x 10^-9 mol/l and the calibration graph is linear in the concentration range 8 x 10^-9 to 1 x 10^-5 M NO2-. The relative standard deviation is 1.8% for 1 x 10^-6 M and 2.9% for 3 x 10^-8 M NO2-, respectively. The detection limit of nitrate (S/N=3) is 4 x 10^-9 mol/l and the calibration graph is linear in the range 8 x 10^-9 to 1 x 10^-5 M NO3-. The relative standard deviation is 2.1% for 1 x 10^-6 M and 3.6% for 1 x 10^-7 M NO3-, respectively. The interferences of cations are eliminated passing the sample through a cation-exchange column. Common anions do not interfere. Analysis time is 2.5 min. The concentrations of nitrites and nitrates found by presented method in different water samples were in a good agreement with those obtained by spectrophotometric or chromatographic method, respectively.

"Chemiluminescent Flow Injection Analysis Of Nitrates In Water Using On-line Ultraviolet Photolysis"
Anal. Chim. Acta 2002 Volume 474, Issue 1-2 Pages 99-105
Pavel Mikuska and Zbynek Vecera

Abstract: A sensitive, fast and non-toxic flow injection method for the chemiluminescent determination of trace amounts of nitrate in water is presented. Nitrate is on-line reduced to nitrite due to absorption of UV light at quartz capillaries and formed nitrite is instantly determined as peroxynitrite by the chemiluminescent reaction with luminol. An UV photo-reductor consisting of a high-pressure mercury lamp and two quartz capillaries provides an effective reduction of nitrate even though only deionized water as a carrier is employed. Efficiency of nitrate conversion to nitrite is 56±3%. The detection limit of nitrate is 4 x 10^-9 M (0.248 µg/l). Linear range of the method is 8 x 10^-9 to 1 X 10^-5 mol/l of nitrate. Cations and common anions do not interfere. Analysis time is 6 min. The method was applied to the determination of nitrate in various real water samples. The results are in a good agreement with a reference chromatographic method. (C) 2002 Elsevier Science B.V. All rights reserved.
Photochemistry

"Flow Injection Chemiluminescence Determination Of Ultra Low Concentrations Of Nitrite In Water"
Anal. Chim. Acta 1995 Volume 316, Issue 2 Pages 261-268
Pavel Mikuska*, Zbynk Veea and Zbynk Zdrhal

Abstract: A new flow chemiluminescence method for the determination of ultra low concentrations of nitrite in water is presented. Nitrite reacts with H-2O-2 in acid medium to form peroxynitrous acid that is subsequently detected as peroxynitrite by the chemiluminescence reaction with alkaline solution of luminol. The detection limit of nitrite is 1 times 10^-9 mol L-1 (for 50 µl samples) and the calibration graph is linear up to 1 times 10^-5 M NO-2-. The relative standard deviations for 1 times 10^-6 M and 3 times 10^-8 M NO-2- are 1.8% and 5.4%, respectively. The interferences of cations are eliminated by passing the sample through a cation-exchange column. Common anions do not interfere. Analysis time is 3 minutes. The results are in good agreement with a standard spectrophotometric method. (39 References)
Nitrite Water Chemiluminescence Interferences Method comparison