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
Website: @unf

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Classification: Environmental -> soil -> water

Citations 6

"Determination Of Simazine In Water Samples By Waveguide Surface Plasmon Resonance"
Anal. Chim. Acta 1997 Volume 338, Issue 1-2 Pages 109-117
C. Mouveta,*, R. D. Harris, C. Maciag, B. J. Luff, J. S. Wilkinson, J. Piehler, A. Brecht, G. Gauglitz, R. Abuknesha and G. Ismail

Abstract: A waveguide surface plasmon resonance biosensor, equipped with low-index glass waveguides and a 10 mW He-Ne laser (632.8 nm), was evaluated for determining simazine in natural waters. The interaction length (3 mm) of the biosensor was coated with a Au film (53±3 mm thickness) and a triazine derivative, 4-chloro-6-(isopropylamino)-1,3,5-triazine-2-(6'-amino)caproic acid. The biosensor was incorporated into a FIA system and PBS of pH 7.4 was used as the carrier stream. The assays were carried out by incubating the buffered sample with simazine antibodies for 5 min. A portion (100 µL) of the solution was injected into the FIA system and the carrier stream flow was stopped for 8 min when the sample plug reacted the detector cell to allow the free antibodies to react with the immobilized triazine derivative. After recording the signal the biosensor was regenerated by pumping 2 g/l pepsin in PBS of pH 1.9 and 1% propionic acid in aqueous 50% acetonitrile. The system was calibrated for up to 100 µg/l simazine, the detection limit was 0.2 µg/l and the day-to-day RSD (n = 5) were The cross reactivities of atrazine and terbutylazine were 61% and 62%, respectively. The method was applied to surface and ground water samples and the results were confirmed by chromatographic analysis. The method was not suitable for analyzing soil water samples due to the strong non-selective polyanion-polycation binding to the transducer surface.
Simazine Sensor Sensor Interferences Stopped-flow Immobilized reagent

"Procedures For The Storage And Digestion Of Natural Waters For The Determination Of Filterable Reactive Phosphorus, Total Filterable Phosphorus And Total Phosphorus"
Anal. Chim. Acta 1998 Volume 375, Issue 1-2 Pages 5-47
W. Maher* and L. Woo

Abstract: A review, with 150 references, is given. An overview of the forms of P species likely to be encountered in natural waters and the implications for the measurement of filterable and total P is given. Procedures reported in the literature for the storage and digestion of water samples for filterable reactive P (FRP), total filterable P (TFP) and total P (TP) measurements are summarized and the advantages and limitations of methods discussed. Water samples for FRP and TFP measurements need to be filtered immediately on collection as exchange on and off particles may occur in the sample container. Slow freezing of filtered or turbid water samples in acid washed low density polyethylene bottles appears to be satisfactory for the long term storage (years) of a variety of water sample types. Storage of water samples at room temperature or refrigeration (1-5°C) with a preservative is suitable only for short term storage (days-months). If water samples contain <20 µg P/L, adsorption to containers may be significant. Batch digestion of samples with alkaline or acid peroxodisulfate using autoclave or microwave heating offers the advantages of ease, simplicity and precision. Good recoveries of P from a range of P compounds containing P-O-P, C-O-P and C-P bonds expected in natural waters have been reported. If turbid samples are to be analyzed, caution must be exercised to ensure that the C or suspended solids concentration. does not exceed the capacity of the digestion procedure to oxidize the C present and release occluded P from particulate materials. Better recoveries of P from turbid water samples are achieved using microwave heating with closed vessels, probably because of the higher temps. and pressures generated. The use of online heating (microwave, thermal induced) coupled with flow injection analysis and using peroxodisulfate or an oxidizing acid mixture should also allow the automation of TFP and TP measurements. Reliable procedures for the removal of unwanted particulate material prior to or after the digestion step need to be developed.
Phosphorus Sample preparation Review

"Techniques For Preserving And Determining Aluminium Fractions In Soil Solution From Podzolic Forest Soils"
Chemosphere 1998 Volume 36, Issue 4-5 Pages 1143-1148
Kirsti Derome, John Derome and Antti-Jussi Lindroos

Abstract: The purpose of the study was 1) to determine techniques for minimizing the effects of transportation and storage on the concentrations of different Al fractions in soil solution samples, and 2) to determine a suitable method for analyzing monomeric Al concentrations in water samples from humus-rich podzolic soils. Aluminium fractionation was performed on a cation exchange column and the fractions were analyzed by ICP/AES and FIA. A time lag of a few hours to two days between sampling and pretreatment appeared to have no effect on total Al concentrations, even though the samples were not preserved with acid. Freezing the samples was not an appropriate storage technique because it resulted in a strong decrease in total Al concentrations. Storage (+4°C) had a detrimental effect on the proportion of exchangeable monomeric Al, but this problem was overcome by fractionating the samples immediately on arrival at the laboratory. Adjustment of sample pH to <3.7 permitted storage of the fraction for at least 2 weeks before analysis by ICP/AES or FIA. Either of these two techniques can be used for determining exchangeable monomeric Al, but if the non-exchangeable reactive Al fraction (i.e. organically complexed Al) is required then analysis by FIA is necessary.
Aluminum, labile Sample preparation

"A Field-based Spectrophotometric Flow Injection System For Automatic Determination Of Chloride In Soil Water"
Environ. Monit. Assess. 1995 Volume 36, Issue 3 Pages 217-228
Nicholas M. Holden, John F. Dowd, Andrew G. Williams and David Scholefield

Abstract: A field-based method for analysis of chloride in soil water samples relies on a low-cost spectrophotometric detector. A personal computer links and controls three sub-systems: a custom sampling scheme composed of ceramic cup suction samplers and sample traps; a sample routing sub-system; and a sample analysis network using flow injection for analysis by photo-diode detector. Field trials demonstrated the utility of the approach for chloride determination.
Chloride Spectrophotometry Computer Photodiode Portable

"A Modified FIA System For The Determination Of High Levels Of Quickly Reacting Aluminum In Aqueous Solutions"
Int. J. Environ. Anal. Chem. 1996 Volume 62, Issue 2 Pages 115-128
D. Berggren; A. Spar&eacute;n

Abstract: We have modified Clarke et al.'s (1992) flow injection system for determining 'quickly reacting Al' (Alqr) in natural waters, to make it applicable also to solutions having high (>1 mM) aluminium concentrations. By decreasing the flow rate of the carrier stream, thus diluting the sample on-line, and using a very small injection volume (12 µL), the upper end of the linear range has been increased from 2 mg Al/l to at least 30 mg/L. Good repeatability (RSD ≈1-3%, n = 4) was obtained, both for standard solutions and for natural waters. The quantification limit was about 100 µg/L and the sample throughput ~120 injections/h. Validation with synthetic model systems (Al plus F and Al plus citrate) showed that the modified set-up gave a fractionation similar to the one of Clarke et al.'s original system. The modified set-up was also tested on soil solutions, having Al qr concentrations in the range of 0.1 to 1.5 mM. The sensitivity to iron interference was largely reduced by the modification. However, determining Alqr in samples from real rat stomachs, having both high Fe(III) and protein concentrations, caused an interference from Fe(III) at concentrations lower than for standard solutions.
Aluminum Spectrophotometry Dilution

"Study On The Systematic Analysis Of Squeezed Water From Soil By Flow Injection Analysis"
Yankuang Ceshi 1991 Volume 10, Issue 3 Pages 166-170
Lin, S.L.;Shuai, Q.;Qiu, H.O.

Abstract: Sample (2 to 5 ml) was systematically analyzed in the sequence of (i) conductivity, (ii) pH value, (iii) HCO3- by flow injection analysis (FIA) - gas diffusion method, (iv) K+, Na+, Ca2+ and Mg2+ by FIA - AAS, (v) Cl- by FIA - photometry and (vi) SO42- by FIA - turbidimetry. All required procedures were described (details illustrated) for the complete scheme and for the three FIA systems. These methods were time saving and highly reproducible. Results agreed well with calculated values of synthetic samples.
Water Conductometry Spectrophotometry Turbidimetry Gas diffusion pH