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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Adrian P. Wade

Abbrev:
Wade, A.P.
Other Names:
Adrian Paul Wade
Address:
30 11551 Kingfisher Dr, Richmond, BC V7E 3N5 Canada
Phone:
+1-604-275-3952
Fax:
NA

Citations 12

"Spectrophotometric Method For Determination Of Sulfide With Iron(III) And Nitrilotriacetic Acid By Flow Injection"
Talanta 1992 Volume 39, Issue 3 Pages 299-312
Michael D. Kester, Paul M. Shiundu and Adrian P. Wade*,

Abstract: The manual colorimetric method described previously (Anal. Chim. Acta, 1990, 237, 361) has been adapted to flow injection analysis. The calibration graph was rectilinear from 20 to 100 ppm of S2-, with coefficient of variation (n = 10) 1.2% (0.37% at 60 ppm). The method was applied to pulp liquors and wash waters, with coefficient of variation (n = 10) from 0.46 to 1.77%. A manual colorimetric method for determination of sulfide was adapted to flow injection, systematically optimized, and more fully characterized. Its intended application was for measurement of Na sulfide reagent strength in pulp process streams, and sulfide contamination in effluent from Kraft pulp mills. In the flow injection method developed, a sample solution containing sulfide was reacted with a mixture of iron(III) and NTA under ammoniacal conditions. The absorbance of the intensely colored green product of this reaction was measured at 636 nm. Excess sulfite was present as a color stabilizer. A linear dynamic range of 20-100 ppm sulfide was readily achieved; the relative standard deviation was <1.2% (n = 10) throughout this range, and 0.37% (n = 10) midrange at 60 ppm. The usable dynamic range was 8-250 ppm sulfide. Long-term stability of the method was ensured by periodically performing an automatic cleaning cycle using HCl wash solution This prevented tube discoloration and removed any ppts. formed under strongly alkaline conditions. The sample throughput rate was 30/h, given alternate acid wash cycles.
Sulfide Pulp Process liquor Spectrophotometry Optimization Linear dynamic range

"Spectrophotometric Determination Of Palladium With Sulfochlorophenolazorhodanine By Flow Injection"
Talanta 1990 Volume 37, Issue 3 Pages 329-336
Paul M. Shiundu, Peter D. Wentzell and Adrian P. Wade*

Abstract: A computer-controlled flow injection system (Betteridge et al., Anal. Chem., 1986, 58, 2258) with 70 µL injection loop, peristaltic pumping and a 30 µL 1-cm pathlength detection cell is used with diode-array detection at 488 nm for determination of Pd at pH 5. The sample injection medium was 1 mM HCl, the reagent stream contained the Na salt of the cited reagent at 0.94 mM buffered with pH 2 Universal buffer and 0.2 M NaOH and the carrier stream was aqueous solution The rectilinear calibration range was from 0.045 to 30 µg mL-1. Interference studies are reported for 19 metal ions.
Palladium Spectrophotometry Computer pH Buffer Calibration Interferences

"Spectrophotometric Determination Of Peroxydisulfate With O-dianisidine By Flow Injection"
Can. J. Chem. 1990 Volume 68, Issue 10 Pages 1750-1756
Paul M. Shiundu, Adrian P. Wade, and S.B. Jonnalagadda

Abstract: The method is based on the Cu(II)-catalyzed oxidation of o-dianisidine (I) by S2O82- (II) in the flow injection system of Wentzell et al. (J. Autom. Chem., 1989, 11, 227) to give a product with λmax = 450 nm. The sample (e.g., 100 µL) was injected into a stream of 0.5 mM Cu(II) (1.5 mL min-1) and mixed with a stream of 10 mM I (0.5 mL min-1) in aqueous 40% acetone in a 50-cm coil before being mixed with a stream of 0.1 M 3,3-dimethylglutaric acid (0.5 mL min-1) in 1 M NaCl (pH adjusted to 7.0 with NaOH) in a further 50-cm coil. The manifold was constructed from PTFE tubing (i.d. 0.5 mm). Calibration graphs based on the absorbance at λmax were rectilinear for 25 to 750 µM-II; the detection limit was 0.5 µM. In the determination of 25 µM-II the coefficient of variation was 1.5% (n = 10). There was little interference from 2.5 M methanol, 1.0 M ethanol or 0.25 M prop-2-en-1-ol, some interference from 0.25 M prop-2-enyl acetate and 0.5 M ethyl acetate and serious interference from formaldehyde.
Peroxydisulfate Polymer Spectrophotometry Catalysis pH Interferences

"Optimization Of Conditions For Flow Injection Analysis"
Anal. Proc. 1984 Volume 21, Issue 10 Pages 373-374
A. P. Wade

Abstract: A short review is presented, with 20 references.
Computer Optimization Review

"Optimization Of Flow Injection Analysis And Polarography By The Modified Simplex Method"
Anal. Proc. 1983 Volume 20, Issue 10 Pages 523-527
A. P. Wade

Abstract: The modified Simplex method is outlined, and its application to the optimization of single-, two- and multiple-factor responses in flow injection and polarographic analyzes and in ninhydrin amino-acid analysis, respectively, is reviewed. The method allows efficient optimization of several variables simultaneously, and is usually faster and more reliable than univariate methods. (13 references)
Amino Acids Polarography Computer Optimization Review Modified simplex Theory Review

"Computer Assisted Optimization Of Chemical Systems, In Particular Flow Injection Analysis"
Anal. Proc. 1983 Volume 20, Issue 3 Pages 108-109
A. P. Wade

Abstract: A modified simplex method (cf. Betteridge et al., Anal. Chem., 1983, 55, 1292) is used to optimize experimental conditions for multi-variable chemical systems, e.g., the determination of isoprenaline by flow injection analysis, the sensitivity of the catalytic polarographic wave for the uranyl ion - nitrate system and the reaction between 4-(2-pyridylazo)resorcinol and KMnO4
Isoprenaline Spectrophotometry Computer Optimization Simplex Theory Review

"Generalized Fourier Smoothing Of Flow Injection Analysis Data"
Anal. Chem. 1994 Volume 66, Issue 24 Pages 4507-4513
Oliver Lee, Adrian P. Wade, and Guy A. Dumont

Abstract: The Fourier transform is widely used for smoothing data such as those from flow injection analysis (FIA). The effectiveness of this method can be enhanced if, in addition to the standard complex exponential functions, the Fourier transform is generalized to use other sets of complete, orthogonal functions such as the Gram or Meixner polynomials as its basis functions. The choice of which set of basis functions to use depends on its efficiency on a given peak. Using simulated noisy FIA peaks differing in degree of skewness, it was found that the standard complex exponential set is best-suited for symmetric or nearly symmetric peaks, and the Meixner set, for moderate to greatly skewed peaks. The Gram set weakly favors skewed peaks, but it is not more effective than both the complex exponential and Meixner sets over any portion of the skewness range studied. The problem of determining the optimal spectral cutoff point was cast in terms of hierarchical model selection, and a generalized Akaike information-theoretic criterion (GAIC) was evaluated for its ability to find the best filter order. Use of an efficient basis minimizes the chance of selecting a non-optimal filter order. The combination of generalized Fourier filtering and the GAIC provides an attractive means to filter FIA data automatically.
Fourier transform

"Analysis Of Flow Injection Peaks With Orthogonal Polynomials"
Anal. Chem. 1994 Volume 66, Issue 7 Pages 971-982
O. Lee, G. A. Dumont, P. Tournier, and A. P. Wade

Abstract: Representation of the response curves of FIA by a generalized Fourier expansion in discrete orthogonal polynomials is described. Both Gram and Meixner (Laguerre) polynomials were evaluated for the purpose. The theory of each approach is presented, and each was used to simulate peaks of various types and to process the data from the reaction between Fe(II) and 1,10-phenanthroline at different flow rates and pH values monitored at 508 nm. Principal components analysis was used for pattern recognition and the program MATLAB (MathWorks, Natick, MA, USA) was used for the Fourier analysis. The Laguerre spectrum required optimization of a time scale parameter, for which a method is given. A balance between peak discrimination ability and insensitivity to noise was provided by 20-25 Gram coefficients or 7-10 Laguerre coefficients, and peaks of abnormal shape were readily identified.
Iron(2+) Spectrophotometry Optimization

"Development Of Catalytic Photometric Flow Injection Methods For The Determination Of Selenium"
Anal. Chem. 1991 Volume 63, Issue 7 Pages 692-699
aul M. Shiundu and Adrian P. Wade

Abstract: A carrier stream of 0.1 M phenylhydrazine hydrochloride was merged with a flow of 0.5 M KClO3 to give a total flow rate of 1.0 mL min-1. The mixture was passed via an injection valve, where the Se(IV) sample was added to, a 50-cm reaction coil. Two other channels of 1.2 M HCl (0.5 mL min-1) and 0.02 M chromotropic acid (0 to 1 mL min-1) were merged before all the streams were passed through a 300-cm reaction coil at 60°C. The absorption of the red complex was measured at 360 nm using a diode-array spectrophotometer. The reaction followed pseudo-first-order kinetics. Interference studies showed that most metal ions could be tolerated at 100 ppm and others could be masked with EDTA. The performance of the optimized conventional flow injection manifold was compared with that of stopped-flow and flow-reversal configurations. The conventional manifold had a sample throughput rate of >60 h-1, a detection limit of 0.52 ppm of Se(IV) and a rectilinear range of 0 to 50 ppm. When the sample plug was stopped for 30 s, the sensitivity was increased by a factor of 2.5 while maintaining a throughput of 45 h-1. At this rate, the flow-reversal method gave improved sensitivity and a detection limit of 0.15 ppm. A reverse trend of conventional >stopped-flow >flow reversal was observed for the rectilinear dynamic range.
Selenium Spectrophotometry Catalysis EDTA Heated reaction Kinetic Interferences Optimization Reverse Stopped-flow

"A Random Walk Simulation Of Flow Injection Systems With Merging Zones"
Anal. Chim. Acta 1987 Volume 194, Issue 1 Pages 49-60
C. D. Crowe and H. W. Levin, D. Betteridge and A. P. Wade

Abstract: A flow-injection system with merging zones is simulated by using a random-walk stochastic (Markovian chain) model. Variables studied include reagent plug size and offset, reagent concentration and flow rate, injection delay time, reaction stoichiometry, rate constant, diffusion constants, viscosity, and temperature. The reaction of Ca(II) with o-cresolphthalein complexone was used to compare simulated and experimental results. In general, there was good agreement among computed and measured results.
Calcium Spectrophotometry Diffusion coefficients Merging zones Random walk Rate constants Simulation Stoichiometry Temperature Theory Viscosity

"A Random Walk Simulation Of Flow Injection Analysis"
Anal. Chim. Acta 1984 Volume 165, Issue 1 Pages 227-236
D. Betteridge, C. Z. Marczewski and A. P. Wade

Abstract: Dispersion and chemical reaction in a single-channel flow-injection system are modelled by a random walk (stochastic, Markovian chain) method using a microcomputer. The effects of various simulated physical variables are investigated. The model provides valuable insight into the mixing process in flow injection analysis.
Computer Theory Simulation Random walk

"The Spectrophotometric Determination Of Hydroxylamine Alone And In The Presence Of Hydrazine By Flow Injection Analysis"
Anal. Chim. Acta 1983 Volume 153, Issue 1 Pages 277-280
G. C. M. Bourke, G. Stedman and A. P. Wade

Abstract: The method is based on the manual procedure of Dias et al. (Anal. Abstr., 1979, 37, 2B143). The sample solution was mixed with a three fold volume of 10 mM ferrozine [3-(2-pyridyl)-5,6-bis-(4-sulfophenyl)-1,2,4-triazine (monosodium salt)], a 0.41 mL portion was injected into a carrier stream (1.19 mL min-1) of 0.3 M chloroacetic acid - 0.273 M NaOH - 3.1 mM Fe(III), and the absorbance was measured with use of the flow-through photo-transducer of Sly et al. (J. Autom. Chem., 1982, 4, 186), which incorporated a light-emitting diode (giving max. emission at 565 nm) and a phototransistor. Calibration graphs were rectilinear for 10 µM to 0.1 mM hydroxylamine in the sample solution, the limit of detection was 1 µM, and the repeatability of peak heights was 0.7%. A 20-fold excess of hydrazine can be tolerated; when larger amounts are known to be present, hydrazine can be determined separately and a correction applied.
Hydroxylamine Water Spectrophotometry Computer Optimization Light emitting diode Photodiode