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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David Betteridge

Abbrev:
Betteridge, D.
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BP Research Centre, Chertsey Road, Sunbury-on-Thames, Middlesex, England
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Citations 17

"Reflections On The Modified Simplex - 1"
Talanta 1985 Volume 32, Issue 8 Pages 709-722
D. Betteridge* and A. P. Wade, A. G. Howard

Abstract: The modified simplex method is a well-known method of optimization. In this study several changes have been made to it. These include an adaptive weighted centroid and a Lagrange interpolation procedure. The latter is used to get a better value of the reflected point when a contraction succeeds or an expansion fails. The new method, called the composite modified simplex method (CMS) has been rigorously evaluated by means of mathematical functions, maps and chemical experimentation. The effect of the starting point and the size of the simplex have been investigated in detail. For flow-injection analysis it has proved possible to optimize 2-12 variables. The method has proved most suitable for rapid and effective optimization of polarography, flow-injection analysis and chemical synthesis. This paper describes the evaluation procedures and reviews the results obtained.
Optimization Modified simplex

"Two-point Kinetic Simultaneous Determination Of Cobalt(II) And Nickel(II) In Aqueous Solution Using Flow Injection Analysis"
Fresenius J. Anal. Chem. 1983 Volume 314, Issue 4 Pages 386-390
D. Betteridge and Bernard Fields

Abstract: The different rates of the dissociation of the citrate complexes of cobalt(II) and nickel(II) at pH 9.25 are used as a basis for the two point kinetic assay of these ions at ppm levels in a flow injection analysis sytem. The reactions are followed by measuring the absorbance of complexes of the metal ions with 4-(2-pyridylazo)resorcinol (PAR) which are formed in a subsequent rapid reaction. EDTA is added to prevent interference from copper(II), manganese(II), zinc(II), chromium(III), lead(II) and vanadium(V) at 10 ppm. Determinations are made with errors of < 10% and at the rate of 30 samples per hour. The precision compares well with results for similar methods by other workers. These results and results by other workers show that this type of method suffers from poor precision in one analyte if the other analyte has a much higher concentration. It is however cheaper than others and has a greater sample throughput.
Cobalt(II) Nickel(II) Water Spectrophotometry Kinetic Simultaneous analysis

"Flow Injection Analysis In The Teaching Laboratory"
Fresenius J. Anal. Chem. 1982 Volume 312, Issue 5 Pages 441-443
D. Betteridge

Abstract: Experiences in the teaching laboratory with a very simple form of flow injection analysis, in which a constant head is used to propel the carrier stream and the detector is made by a combination of light emitting diode and phototransistor, are described and discussed.
Copper Cobalt Iron Lead Manganese Nickel Education Review

"Analytical Chemistry - The Numbers Game"
Chem. Br. 1980 Volume 16, Issue 12 Pages 646-650
Betteridge, D.

Abstract: The development of data handling systems for use in chemical anal. to achieve high sample throughput is discussed. (SFS)
Review

"Simulation And Modeling In Chemical Analysis"
Anal. Proc. 1984 Volume 21, Issue 4 Pages 139-140
D. Betteridge

Abstract: A short review, with 4 references, is presented of computer simulation and modeling in the optimization of an auto-analyzer., in the application of queuing theory to the analysis of sample throughput and in simulation of flow injection analysis.
Computer Modeling Optimization Review Simulation

"Flow Injection Techniques. Analytical Chemistry At The Interface"
Anal. Proc. 1981 Volume 18, Issue 1 Pages 26-31
D. Betteridge, E. L. Dagless, B. Fields, P. Sweet and D. R. Deans

Abstract: In our work we have been concerned exclusively with exploiting the chemical and physical changes that take place across the interfacial region. Insofar as we are dealing with fast reactions in flow systems, two practical problems arise in pursuing this investigation. The first is an instrumental one, resulting from the need to measure concentration profiles across the sample and to process the data obtained. This problem requires the development of sensitive flow detectors that are compatible with digital computers. The second problem is in sorting out and taking advantage of the chemistry that occurs in the few seconds which elapse between the points of injection and detection. This paper presents a progress report of this long-term study.
Copper Manganese Refractometry Diffusion coefficients Gradient technique Theory

"Control Of Dispersion And Variation Of Reaction Coil Length In Flow Injection Analyzers By Flow Reversals"
Anal. Chem. 1987 Volume 59, Issue 8 Pages 1236-1238
D. Betteridge, P. B. Oates, and Adrian P. Wade

Abstract: Procedures (diagrams given) were adopted to study the control of dispersion and of variations in reaction coil length, by flow reversal: single reversal without reactions, single reversal with reaction and multiple reversals without reaction. These allow the plug to be moved effectively any distance. Results from the three experiments showed that flow reversal optimized automated flow injection analysis.
Dispersion Flow reversal Mixing coil Optimization Review Theory

"Versatile Automatic Development System For Flow Injection Analysis"
Anal. Chem. 1986 Volume 58, Issue 11 Pages 2258-2265
D. Betteridge, Timothy J. Sly, Adrian P. Wade, and Derrick G. Porter

Abstract: A computer-controlled automatic analyzer. for flow injection analysis is described and illustrated. It permits the variation of flow rates, pH and reagent concentration. in one or more sample or carrier streams. Detection is by a flow-through transducer. The system is optimized by the analysis of isoprenaline and coefficient of variation are 0.62 and 0.53% by manual and automated operations, respectively, with a flow cell of 1.0 mm path-length. The optimum flow rate, pH and reagent concentration. are 0.63 mL min-1, 7.4 and 7.36 mM, respectively. The system has been applied to the simultaneous determination of Co(II) and Mn(II).
Isoprenaline Spectrophotometry Computer Optimization Simplex

"Computer-assisted Optimization For Flow Injection Analysis Of Isoprenaline"
Anal. Chem. 1983 Volume 55, Issue 8 Pages 1292-1299
D. Betteridge, Timothy J. Sly, Adrian P. Wade, and John E. W. Tillman

Abstract: The spectrophotometric determination of isoprenaline with K3Fe(CN)6 has been adapted to flow the variables were flow rate, length of the reaction coil, reagent concentration, pH and, sometimes, sample size. The software was written in BASIC. When the first four and all five variables were considered, the proposed simplex method required 34 and 37 experiments and the univariate procedure 88 and 168 experiments, respectively. The optimized flow injection determination of isoprenaline at the ppm level is simpler than the manual spectrometric method; the best sensitivity is maintained at a throughput of 45 samples h-1.
Isoprenaline Spectrophotometry Computer Optimization Modified simplex

"Flow Injection Analysis"
Anal. Chem. 1978 Volume 50, Issue 9 Pages 832A-846A
D. Betteridge

Abstract: Flow injection analysis, a continuous-flow analysis technique in which the sample is injected directly into the carrier stream without air segmentation, is reviewed with 48 refs.
General Review Theory

"Construction Of PH Gradients In Flow Injection Analysis And Their Potential Use For Multielement Analysis In A Single Sample Bolus"
Anal. Chem. 1978 Volume 50, Issue 4 Pages 654-656
D. Betteridge and Bernard Fields

Abstract: The resoln. of absorbing species of the chelates of 4-(2-pyridylazo)resorcinol (PAR) with Pb(II) and V(V) was used to demonstrate the feasibility of multielement determination across a single sample bolus in flow injection analysis The separation of the resulting peaks is made possible by establishing a pH gradient across the sample carrier interfaces by arranging the pH values of the samples and carrier stream to be different. The nature of the flow and mixing processes which make this possible are discussed.
Lead(2+) Vanadium(V) Spectrophotometry Multielement Chelation pH gradient Injector Review Theory

"The Application Of PH Gradients In Flow Injection Analysis. Method For Simultaneous Determination Of Binary Mixtures Of Metal Ions In Solution"
Anal. Chim. Acta 1981 Volume 132, Issue 1 Pages 139-155
D. Betteridge and Bernard Fieldas

Abstract: Under static conditions, pH-absorbance curves are highly characteristic for a given metal ion-ligand combination. If the ligand is an unselective analytical reagent, such as 4-(2-pyridylazo)resorcinol, the pH-absorbance curve obtained by adding the reagent to a mixture of metal ions is similar to a multi-element polarogram. It can be used for the detection of components of the mixture and for their determination. The absence of air segmentation in flow-injection systems means that pH gradients form over the sample/ carrier interface when basic solutions are injected into acid carrier streams, or vice versa. Thus there is the possibility of obtaining pH-absorbance curves under the dynamic conditions of flow injection analysis (f.i.a.). Procedures for the creation of known and reproducible pH gradients are given and discussed. The pH-gradient flow-injection method is evaluated by determining with 4-(2-pyridylazo)resorcinol (PAR) binary mixtures of (a) cobalt(II) and manganese (II) and (b) nickel(II) and copper(II) in the presence of similar amounts of cobalt(II) in the ppm range. In the latter example cobalt is kinetically masked by virtue of the relatively slow dissociation of the Co(HPAR)+ complex. Wide or narrow pH changes may be used, the choice being dependent on the critical pH range for complexation. The procedure is simple and accurate, and may be suitable for the rapid determination of a range of mixtures.
Manganese(II) Nickel(II) Copper(II) Cobalt(II) Spectrophotometry Simultaneous analysis pH gradient Photodiode

"Development Of A Flow Injection Analyzer For The Post-column Detection Of Sugars Separated By High Performance Liquid Chromatography"
Analyst 1984 Volume 109, Issue 1 Pages 91-93
D. Betteridge, N. G. Courtney, T. J. Sly and D. G. Porter

Abstract: Reducing sugars were separated by HPLC on a column (25 cm x 4 mm) of Spherisorb S5-NH2 with aqueous 75% acetonitrile as mobile phase. Aliquots (12 µL) of the eluate were injected automatically at fixed intervals into the flow injection analysis system, where the reducing sugars reacted with 2,3,5-triphenyltetrazolium chloride under alkaline conditions (0.02 M NaOH) to form a formazan, the absorbance of which was measured at 564 nm; details of the post-column detection system are given (with a diagram). Calibration graphs were rectilinear from 1 to 10 g L-1 for monosaccharides and 1 to 20 g L-1 for disaccharides.
Carbohydrates Fructose Glucose Lactose Maltose HPLC Spectrophotometry Post-column derivatization

"Automated Viscometer Based On High-precision Flow Injection Analysis. 2. Measurement Of Viscosity And Diffusion Coefficients"
Analyst 1983 Volume 108, Issue 1282 Pages 17-32
D. Betteridge, W. C. Cheng, E. L. Dagless, P. David, T. B. Goad, D. R. Deans, D. A. Newton and T. B. Pierce

Abstract: The use of the apparatus described in Part I (Ibid, 108, 1983, 1) as a viscometer and for the measurement of diffusion coefficient has been evaluated. The effects of radius and length of the tube, sample volume and flow rate were studied. The viscosities of 15 solvents were measured. Diffusion coefficient for KMnO4 in water, ethanol and acetone were obtained.
Viscosimetry Computer Diffusion coefficients Titrations Viscosity

"Automated Viscometer Based On High-precision Flow Injection Analysis. 1. Apparatus For High-precision Flow, Injection Analysis"
Analyst 1983 Volume 108, Issue 1282 Pages 1-16
D. Betteridge, W. C. Cheng, E. L. Dagless, P. David, T. B. Goad, D. R. Deans, D. A. Newton and T. B. Pierce

Abstract: An automated viscometer was developed by modifying an Ostwald viscometer in which the sample (~50 µL) was injected into a carrier stream flowing along a narrow-bore tube. The time taken for the sample to travel a fixed distance was directly proportional to the viscosity. The measurement took ~30 s and gave a precision of 0.2 to 0.3% for viscosities ranging from 0.2 to 190 cP. The system could also be used for continuous monitoring of a carrier stream of unknown viscosity by injecting a sample of known viscosity. The use of refractometric, spectrophotometric, photometric, dielectric and conductometric detectors was evaluated and several microcomputer systems were investigated. The temperature had to be controlled to within 0.02°C
Conductometry Refractometry Spectrophotometry Viscosimetry Apparatus Computer Titrations Viscosity

"The Impact Of Microprocessors On Analytical Instrumentation. A Review"
Analyst 1981 Volume 106, Issue 1260 Pages 257-282
D. Betteridge and T. B. Goad

Abstract: In the last 6 years, microprocessors* have progressed from being a novel, exciting development of potential interest to analytical chemists into part of the everyday experience of the populace. Technical advances are still being made at a phenomenal rate, but it is possible now to survey the scene from the point of view of the analytical chemist to assess the impact of microprocessors on analytical instrumentation, to make some sense of the technical aspects and the jargon used to describe them, and to discuss approaches to the application of the microcomputer. It is therefore practical and economic to use them in small-scale inst rumentation such as titrators, polarographs and balances. Two years ago, it was less profitable to use microcomputers for large instruments such as mass spectrometers because of their relatively small memory and speed of operation. However, improvements have been so rapid that these considerations are now less relevant. In analytical instrumentation they can fulfil a control function, which may range from a simple replacement of mechanical or electromechanical parts with a chip, to execution of a program of sequential operations that comprise the total analytical determination. In addition, they may be used with advantage for data acquisition and for data processing, great advances having been made in respect of the latter over the last year. These aspects are discussed in detail in this paper, but first the development of microprocessors and the current availability of microcomputers will be reviewed.
Automation Computer Review

"A Highly Sensitive Flow-through Phototransducer For Unsegmented Continuous-flow Analysis Demonstrating High-speed Spectrophotometry At The Ppb Level And A New Method Of Refractometric Determinations"
Analyst 1978 Volume 103, Issue 1230 Pages 897-908
D. Betteridge, E. L. Dagless, B. Fields and N. F. Graves

Abstract: A simple photometric detector is described which, because of the high stability of the light source, permits determinations of metal ions at the parts per 109 level with 4-(2-pyridylazo)resorcinol as the spectrophotometric reagent. By virtue of the design of the transducer it also functions as a refractometer capable of determinations of solutions of organic and inorganic compounds down to a lower limit of approximately 0.01%m/m. The theory of this function is discussed.A gallium phosphide light-emitting diode and a silicon phototransistor act as light source and sensor, respectively. The output current from the phototransistor is converted into voltage by the current to voltage converter described.The transducer is designed as a flow-through cell which, when used in conjunction with standard unsegmented continuous-flow apparatus, is capable of sampling rates of up to 300 per hour with a relative standard deviation of the result of 1.5%. At slower flow-rates, with a sampling rate of 160 per hour, the relative standard deviation is less than 1%.
Cobalt Copper Spectrophotometry Refractometry Apparatus Detector Flowcell Light emitting diode Photodiode Refractive index PPB