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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Citations 28

"Flow Injection Analyzer For Students, Teaching And Research. Spectrophotometric Methods"
Anal. Chim. Acta 1982 Volume 134, Issue 1 Pages 55-71
J. Rika, E. H. Hansen and A. U. Ramsing

Abstract: The flow streams in simple manifolds are propelled by controlled gas pressure; ancillary equipment consists of a small spectrophotometer or colorimeter and a chart recorder. The analytical result is available in less than 20 s after sample injection, with a reproducibility better than 1%, using microlitre volumes of sample and less than millilitre volumes of reagent per assay. These are the performance data of a simple, robust and inexpensive flow injection analyzer designed for use with a wide range of detectors. The application spectrophotometry is illustrated by five exercises aimed at teaching instrumental analysis and intended for those who wish to introduce flow injection analysis in their laboratories.
Calcium Chloride Chromium(VI) Fluorescence Luminescence Potentiometry Spectrophotometry

"Sandwich Techniques In Flow Injection Analysis. 1. Continuous Recalibration Techniques For Process Control"
Anal. Chim. Acta 1987 Volume 199, Issue 1 Pages 191-196
J. Alonso, J. Bartrolí, M. Del Valle, M. Escalada and R. Barber

Abstract: The technique of sample insertion between two different standard solution used as carrier streams is described. The proposed re-calibration technique enables the construction of simple, reliable and cheap automatic monitors for process control; relatively frequent re-calibration is required for quantitative measurements. Spectrophotometric and ion-selective electrode monitoring procedures are outlined.
Electrode Potentiometry Spectrophotometry

"Plant Tissue-based Amperometric Electrode For Eliminating Ascorbic Acid Interferences"
Anal. Chim. Acta 1990 Volume 234, Issue 2 Pages 315-320
Joseph Wang, Najih Naser and Mehmet Ozsoz

Abstract: Ground courgette tissue (0.4 g) was mixed into a slurry with graphite powder (0.9 g) and mineral oil (0.7 g). A portion of the paste was packed into one end of a 2 mm i.d. glass tube for voltammetry or into the electrode cavity of a thin-layer detector for flow experiments. The presence of ascorbic acid oxidase in the tissue eliminated interference by ascorbic acid. The electrode was applied in the analysis of dopamine and norepinephrine. Uricase-containing pastes were prepared in the same way and co-immobilized to obtain simultaneous elimination of uric acid interferences. The effects of various experimental variables were studied using pulse voltammetry, chronoamperometry and flow injection amperometry. Compared with enzyme-based ascorbic acid oxidase electrodes, the tissue electrode offers high biocatalytic stability and activity at very low cost.
Dopamine Norepinephrine Voltammetry Electrode Amperometry

"Double Injection Enzymatic Flow Analysis Of Glucose Using Amperometric Detection And An Oxygen-permeable Reaction Coil"
Anal. Chim. Acta 1991 Volume 249, Issue 2 Pages 451-460
Xiaowen Wen, H. Kipton, J. Powell, Gary D. Christian and Jaromir Ruzicka

Abstract: A flow injection system for the enzymatic assay of glucose is described. It utilizes double injection of sample and enzyme (glucose oxidase (GOD), ~500 U mL-1) or mixed enzyme (GOD, ~500 U mL-1; horseradish peroxidase (POD), ~220 U mL-1) into an air-saturated phosphate carrier stream (pH 7.0). The reaction products(s) were monitored amperometrically in a three-electrode wall-jet microflow cell (4 µl). Product hydrogen peroxide analysis by pulsed amperometric detection was compared with analysis using the electrode mediators 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and potassium hexacyanoferrate(II). The last method was favored, coupled with oxygen supplementation achieved by use of a gas-permeable silicone-rubber tube reaction coil. This provides a useful curvilinear response to gt 14 mM glucose, with a linear response to ~7 mM; the relative standard deviations for 3.0 and 0.3 mM glucose were 1.3% and 1.8%, respectively, and the detection limit was 0.01 mM glucose using stopped-flow. Both sensitivity and linearity were improved significantly by the use of stopped-flow techniques. Double injection of the sample and enzyme [glucose oxidase (500 U mL-1) alone or mixed with horseradish peroxidase (220 U mL-1)] was made into the carrier stream (0.58 mL min-1) of 0.1 M phosphate buffer, pH 7.0). The solution was mixed with 10 or 50 mM K4[Fe(CN)6] (0.58 mL min-1) as mediator. The H2O2 produced was monitored by its reduction of the mediator at 0.0 V vs. Ag - AgCl. The calibration graph was rectilinear up to 7 mM followed by a curvature to 16 mM. The coefficient of variation (n = 10) were 1.3 and 1.8% for 3 and 0.3 mM, respectively. The consumption of enzyme is greatly lowered, and thus the economic costs of analysis
Glucose Amperometry

"Low-budget Flow Injection Device For Teaching. A $10 Six-port Valve"
Anal. Chim. Acta 1998 Volume 366, Issue 1-3 Pages 217-221
Olaf Elsholz*

Abstract: A novel sample introduction valve, based on the tubing clamp operation principle, is described for teaching flow injection analysis It was developed to overcome the shortage of instrumentation in elementary instruction courses in anal. chemical at Fachhochschule Hamburg. The materials for one valve, which can be easily build-up by the students, is <10.

"Determination Of Aqueous Ozone For Potable Water Treatment Applications By Chemiluminescence Flow Injection Analysis. A Feasibility Study"
Talanta 1992 Volume 39, Issue 6 Pages 593-598
Hyung-Keun Chung, Harvey S. Bellamy and Purnendu K. Dasgupta*,

Abstract: An inexpensive method of generating O3 at concentration. suitable for drinking-water sterilization is presented, together with the use of flow injection chemiluminescence analysis for selective determination of O3. The system comprised a multi-channel peristaltic pump, a dual-loop sample-injection value (electropneumatically actuated) and a laboratory-built flow-through reaction cell positioned in front of a photomultiplier tube. All tubing (0.5 mm diameter) was of PTFE. A number of fluorescing organic compounds was evaluated for the determination of aqueous O3. The limit of detection by using indigotrisulfonate was 2 µg l-1, but chromotropic acid, Rhodamine B (C. I. Basic Violet 10) and eosin Y may be more sensitive. The feasibility of determining aqueous O3 by chemiluminescence (CL) flow injection analysis was studied for application in potable water treatment. The ozonated water sample is injected into a pure water carrier and mixed with a dye reagent in front of a photodetector. Many reagents undergo fast CL reactions with aqueous ozone. Most of these reactions display considerable selectivity for O3 over other oxidants of importance in water treatment. Even when there is steady-state response to another oxidant, significant discrimination against the interferents is possible by taking advantage of the much faster kinetics of the CL reaction with O3. The design of an O3 generator and preparation of standard O3 solutions are described.
Ozone Water Chemiluminescence

"On The Spectrophotometric Flow Injection Determination Of Chromium(VI) In Natural Waters After Online Preconcentration On Activated Alumina"
Talanta 1995 Volume 42, Issue 11 Pages 1609-1617
Mauricio C. Pannain and Ricardo E. Santelli*

Abstract: A minicolumn made of silicone rubber (2.5 cm x 1.6 mm i.d.) was packed with 50 µL activated alumina (Brockman grade 1, particle size range 63-100 µm; Merck, Germany). Sample solution containing Cr(VI) was injected into the column at 5.1 ml/min. The column with adsorbed Cr(VI) was inserted into the eluting stream (0.1 M NH4OH; 2.73 ml/min) and the displaced Cr(VI) was then mixed with 0.7 M HNO3 (0.92 ml/min). The sample was then merged with the reagent stream (0.05% 1,5-diphenylcarbazide; 0.76 ml/min), the color was developed in a reaction coil and the absorbance was measured at 540 nm. Calibration graphs were linear from 10^-50, 2-10 and 1-5 µg/l for 5, 25 and 50 mL sample volumes, respectively. Corresponding detection limits were 3, 0.3 and 0.2 µg/l, respectively. The effects of interferents are tabulated. RSD were 0.6-4.7%. The method was used to determine of Cr(VI) in potable water. The feasibility of chromium(VI) pre-concentration on to activated alumina in a continuous-flow system with spectrophotometric detection was investigated. Chemical and flow variables, and the influence of concomitant species were studied both with and without pre-concentration systems. The best results were obtained by using a 2.5 cm long, 1.6 mm i.d. alumina minicolumn, and selecting 1 x 10^-4 M nitric acid as the pre-concentrating medium and 0.1 M ammonium hydroxide as the eluent. The eluted chromium(VI) was mixed with diphenylcarbazide in acidic medium and the absorbance of the colored complex was measured at 540 nm. Linear calibrations for 5, 25 and 50 mi sample volumes were established over the concentration ranges 10^-50 µg L-1, 2-10 µg L-1 and 1-5 µg L-1 with sensitivity enhancements of 44, 196 and 392 and detection limits (3s) of 3.0 µg L-1, 0.3 µg L-1 and 0.2 µg L-1, respectively. The method is relatively fast and cheap. Natural waters were analyzed with use of the developed procedure. (40 references)
Chromium(VI) Water Environmental Ion exchange Spectrophotometry

"Online Determination Of Sulfide By The Methylene-blue Method With Diode-laser-based Fluorescence Detection"
Analyst 1997 Volume 122, Issue 12 Pages 1555-1557
Michelle A. Spaziani, James L. Davis, Manisha Tinani and Mary K. Carroll

Abstract: The application of an inexpensive, compact, solid-state, fluorescence-based detector for flow injection analysis to the determination of sulfide by the 'Methylene Blue Method', viz., production of Methylene Blue (MB) via the oxidative coupling of sulfide with N,N-dimethyl-p-phenylenediamine (DMPD) in the presence of iron(III), is described. The use of fluorescence-based detection allows the reaction to be performed online under less corrosive, albeit sub-optimum, reaction conditions. The detector uses a 670 nm diode laser as the excitation source and inexpensive photodiodes as detector elements; a color filter (used to block scattered laser light) is the only other optical component of the detector. The fluorescence signal resulting from the MB formed online is linear over the range 0.75-15.0 mg L-1 injected sulfide, with a limit of detection of 0.08 mg L-1 injected sulfide when 9.0 M H2SO4 is used in the DMPD carrier stream, and 1-2 mg L-1 when less acidic carrier streams are employed, Use of this method for analysis of sulfide unknowns in aqueous solution and in a simulated waste water matrix demonstrates that unknown sulfide samples can be analyzed reproducibly. 5 References
Sulfide Waste Fluorescence

"Performance Of A Modular Thermospray Interface For Signal Enhancement In Flame Atomic Absorption Spectrometry Coupled Online To Flow Injection [analysis] Or Liquid Chromatography"
J. Anal. At. Spectrom. 1993 Volume 8, Issue 4 Pages 659-664
Erik H. Larsen and Jean-Simon Blais

Abstract: A simple and inexpensive thermospray interface is described that was connected to a flame AAS system without modification of the nebulizer and burner assembly. Details are provided of its construction and performance characteristics. The interface provided improved signal-noise and signal enhancement in a flow injection - AAS system with rectilinear calibration and detection limits of 1.9 ng of Cd, 8.5 ng of Cu and 27 ng of Pb. The use of the interface to couple HPLC to AAS was demonstrated for the determination of metallothioneins in biological samples.
Cadmium Copper Lead Biological Spectrophotometry

"Fundamentals Of Sinusoidal Flow Sequential Injection Spectrophotometry"
Anal. Chem. 1991 Volume 63, Issue 21 Pages 2407-2413
Thomas Guebeli, Gary D. Christian, and Jaromir Ruzicka

Abstract: A rational design of the sequential injection analyzer is based on description of the mutual penetration of sample and reagent zones, which are sequentially stacked into a tubular conduit and then injected into a reactor and transported toward the detector by means of a carrier stream, flowing at a preprogrammed rate. Variables governing zone penetration have been identified by a series of dispersion experiments, for sequential injection of two and three zones, thus outlining the conditions for performing single- and double-reagent- based assays. A parallel is drawn between conventional flow injection and corresponding sequential injection colorimetric determinations of chloride and phosphate, with the aim of suggesting guidelines for the development of spectrophotometric- and fluorescence-based sequential injection methods. An alternative to flow injection analysis is discussed. With use of a single sinusoidal-flow pump and a selector valve, wash solution, sample zone and reagent zone(s) are injected into a single empty tube. The reversal of flow between intake of these solution and their injection into the tube creates the conditions for mutual dispersion of the zones. The effect of the variables on the degree of dispersion is discussed. The amount of overlap of the zones can be controlled. The combined zones then pass through a reactor to the detector. With fast reactions, the overlapping zone can pass continuously through the detector; with kinetic methods, the flow can be stopped at the appropriate time and the evolution of the signal can be followed. The method is exemplified by the determination of Cl- with a single Hg(SCN)2 - Fe(NO3)3 reagent (fast reaction) and by the determination of phosphate with separate molybdate and ascorbic acid reagents (slow second-stage reaction). The technique may be of use in designing cheaper and more robust process analyzer.s than the flow injection method can provide.
Chloride Phosphate Fluorescence Spectrophotometry

"Flow Injection Analysis Using An Aquarium Air Pump"
Fresenius J. Anal. Chem. 1993 Volume 346, Issue 10-11 Pages 882-884
Kate Grudpan, Colin Taylor, Hans Sitter and Cornelius Keller

Abstract: Propelling systems for FIA that comprise an aquarium air pump in a pressure mode or a suction mode are described. Modifications to such a pump to facilitate rapid sample injection are illustrated. The determination of phosphate with (NH4)6Mo7O24 in the presence of ascorbic acid or ammonium with an FIA manifold in the suction mode and acid-base (HCl-NaOH) titrations in the pressure mode are outlined. The determination of Na, K and Ca by flow injection AES involving an aquarium air pump in the suction mode and a rapid injection valve is illustrated.
Sodium Potassium Calcium Phosphate Acidity Spectrophotometry

"Characterization Of Poly(estersulfonic Acid)-coated Micro-voltammetric Electrodes"
Electroanalysis 1990 Volume 2, Issue 3 Pages 253-256
Joseph Wang*, Meng Shan Lin

Abstract: The micro-electrode was fabricated by coating a glass micro-pipette packed with Dylon graphite paste with a poly(estersulfonic acid) film (details given). The electrode was characterized by voltammetry vs. Ag - AgCl and a Pt auxiliary electrode under flow injection conditions. The attractive permselective, ion-exchange, antifouling and dynamic properties of the polyester ionomer together with its low cost and strong adherence to surfaces could be very valuable for in vivo brain electrochemistry, and offers an effective alternative to Nafion coatings.
Electrode Voltammetry Ion exchange

"Flow Injection Method For The Determination Of Oxalate In Urine Based On A Promoting Effect"
J. Pharm. Biomed. Anal. 1992 Volume 10, Issue 1 Pages 95-98
J. A. Infantes, M. D. Luque de Castro* and M. Valc&aacute;rcel

Abstract: Urine (5 ml) was adjusted to pH 5 to 5.2 with 2 mL of CaCl2 (5 g l-1), the mixture was set aside for 12 h and the calcium oxalate ppt. formed was separated off by centrifugation for 30 min. The ppt. was washed with dilute NH4OH, dissolved in 1 mL of 1N-H2SO4 and a portion of the solution was injected into a flow injection manifold (diagram given) into a stream of 1.4 mM Cr(VI) in 0.53 M H2SO4 which merged with a stream of 0.33 mM ferroin. The mixture was passed through a reaction coil (330 cm long) before the absorbance was measured at 510 nm. The calibration graph was rectilinear from 0.8 to 18 µg mL-1 of oxalate with a coefficient of variation (n = 11) of 2.81%; sampling frequency was 40 h-1. A simple, inexpensive and convenient method for the determination of oxalate in urine was developed. It is based on its promoting effect on the oxidation of ferroin by Cr(VI). It provided a wide linear determination range and acceptable precision and recovery. Its sampling rate makes it suitable for small and medium-sized labs.
Oxalate Urine Spectrophotometry

"Investigation Into Low-cost Flow Injection Analysis"
Anal. Proc. 1989 Volume 26, Issue 2 Pages 48-49
J. F. Tyson

Abstract: An inexpensive detection system was contructed (details given) for spectrophotometric detection in flow injection analysis. A flow cell was designed that incorporated optical-fiber light guides and stainless-steel sample inlet tubes set in a Perspex block, and the detector consisted of a photodiode and a simple amplifier. The system was applied in the determination of Fe(III) with use of ferron, KSCN or Variamine blue RT salt (C. I. 37240). An inexpensive detection system was constructed (details given) for spectrophotometric detection in flow injection analysis. A flow cell was designed that incorporated optical-fiber light guides and stainless-steel sample inlet tubes set in a Perspex block, and the detector consisted of a photodiode and a simple amplifier. The system was applied in the determination of Fe(III) with use of ferron, KSCN or Variamine blue RT salt (C. I. 37240).
Iron(III) Spectrophotometry

"Spectrophotometric Flow Injection Techniques For Process Monitoring"
Anal. Proc. 1989 Volume 26, Issue 11 Pages 385-387
Richard L. Benson, Paul J. Worsfold, Frank W. Sweeting

Abstract: The robust, low-cost analyzer. described for automated water quality monitoring (described) incorporates a solid-state double-beam photometer with both sample and reference flow cells constructed from the same PTFE tubing (diameter 0.8 mm), as used in the rest of the flow manifold. Maximum sensitivity is achieved in the visible and near-IR regions; the red and green bands (635 and 565 nm, respectively) of the light-emitting diode sources are those most commonly used. A sampling unit and data transmission facilities are also included, as well as a supply of reagents for two week's unattended operation. The monitor was field-tested for the determination of NO3- by reduction (by copperized Cd) to NO2- and conventional azo-dye formation. The rectilinear range was 1.5 to 12.0 mg L-1 of nitrate-N, and the precis
Nitrate Environmental Spectrophotometry

"Progress In Water Quality Control: Methods In Continuous Micro-flow And Flow Injection Analysis"
Analusis 1991 Volume 19, Issue 2 Pages i27-i31
SERIZOT P.

Abstract: The cited methods are examined and compared, and their advantages and disadvantages are discussed. The methods allowed the quality control of waste water with minimum automation. The efficiency and cost-effectiveness of the techniques are demonstrated. The choice of technique varied according to specific needs, control conditions requested and priorities peculiar to each laboratory.
Waste

"Simple And Inexpensive Flow Injection Analysis For Determination Of Sucrose Using Invertase And Glucose Oxidase Immobilised On Glass Beads"
Biotechnol. Techniq. 1995 Volume 9, Issue 5 Pages 345-348
V. Leite, I. C. Le&atilde;o, G. F. V. de Vasconcelos, M. C. B. Pimentel, V. L. SIlva, E. H. M. Melo, and J. L. Lima Filho

Abstract: A Flow Injection Analysis (FIA) for sucrose using invertase ( E.C. 3.2.1.26), mutarotase (E.C.5.1.3.3) and glucose oxidase (E.C.1.1.3.4) was developed. The enzymes were immobility on glass beads using glutaraldehyde. The sucrose concentration was related to oxygen saturation. Fall in O-2 concentration, as a result of sucrose oxidation, was detected by a low cost, home-made O-2 electrode. The system was able to measure sucrose from 0.025 to 100 mM with a response time of 6 min using 200 µl of sample, with an apparent K-m of 42 mM of sucrose. The system has been operated satisfactorily for 50 days without loss any initial activity.
Sucrose Electrode

"Flow Injection Analyser For Chemical Oxygen Demand Using Potassium Permanganate"
Chem. Biomed. Environ. Instrum. 1980 Volume 10, Issue 3 Pages 273-288
Takashi Korenaga

Abstract: An apparatus for measuring chemical oxygen demand (COD) in industrial waste water, based on the principle of flow injection analysis (FIA), is described. The apparatus is simple and inexpensive and constructed by components, such as a double plangent pump, sampling valve, flow cell, spectrophotometer and recorder, commercially available for high performance liquid chromatography. Polytetrafluoroethylene (Teflon) tubing is used for mixing coils and transmission lines. The operating conditions are determined by using glucose as the standard COD substance. The peak heights obtained for various concentrations of aqueous glucose solutions correspond to their manual COD values obtained by the JIS (Japan Industrial Standard) method.
Chemical oxygen demand Waste Spectrophotometry

"Assessment Of The Automated Colorimetric And The High Performance Liquid Chromatographic Methods For Nicotine Intake By Urine Samples Of Smokers' Smoking Low- And Medium-yield Cigarettes"
Clin. Chim. Acta 1991 Volume 196, Issue 2-3 Pages 159-166
Sakari A. Kolonen* and Eino V. J. Puhakainen

Abstract: HPLC was essentially as described previously (Arch. Toxicol., Suppl., 1988, 12, 423), whilst the colorimetric barbituric acid (I) test with use of a continuous-flow analyzer. was as described by Puhakainen (Clin. Chim. Acta, 1987, 170, 255). HPLC determined only cotinine, and calibration graphs (treated urine samples) were rectilinear over the concentration. range 0.05 to 1.0 mg L-1 with coefficient of variation in the range 2.4 to 5.0%. The detection limit was 2 µg L-1 and the throughput was 50 per day. I could be used to detect most of the nicotine metabolites, and the calibration graph was rectilinear over the range 0 to 40 mg L-1 cotinine equivalents, with coefficient of variation in the range 2.2 to 4.2%. The subtraction of interference arising from the natural color of urine (cotinine equivalent of ~0.6 to 0.7 mg l-1) reduced the throughput of samples to 150 per day. It was concluded that use of I was an inexpensive and rapid alternative to HPLC for estimating the nicotine exposure of smokers.
Nicotine Urine HPLC Clinical analysis Spectrophotometry

"Flow Injection System Based On The Sandwich Technique For Saving Expensive Reagents"
Clin. Chim. Acta 1991 Volume 203, Issue 1 Pages 67-76
Alberto N. Araujo, Jos&eacute; L. F. C. Lima, Juli&aacute;n Alonso-Chamarro*, Jordi Bartrol&iacute; and Manel Poch

Abstract: We report the application of a sandwich technique in flow injection systems which afford low consumption of expensive reagents and two reagent recirculation systems. The potential applicability of the technique thus developed was assessed by determining glucose in serum samples by the enzymatic glucosidase/peroxidase method. It was possible to perform up to 450 determinations with the same amount of reagent used to perform 50 determinations by batch procedures. The sampling rate was 80 determinations per hour with a 0.9% relative standard deviation. Serum was subjected to flow injection analysis with mixing with phosphate buffer solution (pH 7.4) and 11 mM phenol - 0.8 mM 4-aminoantipyrine - peroxidase (900 iu l-1) - glucose oxidase (15,000 iu l-1) and detection at 520 nm. An eight-port injection valve (cf. Alonso et al., Anal. Chim. Acta, 1987, 199, 191) was used to reduce reagent consumption along with a recycling system for the enzyme reagent solution The within-batch coefficient of variation (n = 10) was 0.9%. The method was used to perform 450 determinations with the same amount of reagent used to perform 50 determinations by the batch procedure. The sampling rate was 80 determinations h-1. The results compared well with those obtained using a Hitachi 735 batch analyzer..
Glucose Serum Human Spectrophotometry Clinical analysis

"The $25 Flow Injection Analyzer - An Affordable Instrument For Every Laboratory"
J. Chem. Educ. 1993 Volume 70, Issue 6 Pages 511-513
Lawrence C. Davis

Abstract: A flow injection analyzer is only a little more difficult to construct than a simple colorimeter at about the same cost. It can yield highly sensitive analyzes with use of small volumes of analyte and 1-2 mL of reagent per sample, generally 5-10-fold less than required for test tube analyzes. Concern for disposal of hazardous substances is leading to miniaturization of many techniques. Use of flow injection analysis can reduce waste prodn. substantially. The design presented here is a minimal one. With an obsolete spectrophotometer as the detector, one could construct a much more versatile instrument having wavelength adjustment. However, a high degree of portability is a virtue of the present set-up, as discussed by Bauer et al. The instruments could be mass produced quite economically once the design is fixed for a particular set of applications.
Protein Spectrophotometry

"An Inexpensive Detector For Absorbance Measurements In Flow Injection Analysis"
J. Chem. Educ. 1996 Volume 73, Issue 2 Pages 191-192
Peter C. Hauser and Norman E. Cates

Abstract: A photometric transducer for peak detection in flow-injection analysis is described. It relies on a light-emitting diode as the light source and a photodiode as the detector. A logarithmic amplifier is used in order to emulate Beer-Lambert's Law and to directly obtain absorbance readings. The performance has been tested with two commonly employed flow-injection procedures, but the device should be suitable for most methods that may be used in the teaching lab.
Spectrophotometry

"Low-cost Flow Injection Analysis For Cadmium Using 2-(2-Benzothiazolylazo)-4,5-dimethylphenol"
J. Environ. Sci. Heal. 1991 Volume 26, Issue 1 Pages 63-74
Kate Grudpan & Chusri Palsaludomsil

Abstract: 2-(2-benzothlazolylazo)-4,5-dlmethylphenol (BTDMP) has been applied as a new color reagent to flow Injection analysis (FIA) for cadmium. The low-cost FIA system used was made and assembled using low-cost and easily available materials. Optimum conditions for the FIA system were Investigated, such as analytical wavelength, a solvent as a carrier, alkalinity of the carrier, concentrations of reagents used, flow-rate and mixing coil length. Using the optimum conditions, a calibration curve was obtained for a linear range of 0-10 ppm Cd. Interferences of some metal ions (Zn, Cu, Co, Nl and Hg) were studied.
Cadmium Spectrophotometry

"Adaptation Of The Bicinchoninic Acid Protein Assay To A Continuous-flow Autoanalyzer"
Lab. Rob. Autom. 1991 Volume 3, Issue 1 Pages 13-17
Hawkes, W.C.;Craig, K.A.

Abstract: The Pierce bicinchoninic acid protein assay method was adapted to a Technicon automated analyzer to give a response comparable to that of the manual procedure. The sampling rate was 30 h-1 and reagent cost was reduced to half that of commercial kits.

"Simultaneous Determination Of Total Calcium And Phosphorus In Milk Using Flow Injection Analysis"
Lab. Rob. Autom. 1998 Volume 10, Issue 4 Pages 235-238
Telis Dimitrakopoulos, John R. Farrell, Peter J. Iles

Abstract: The design, development, and testing of a flow injection analysis (FIA) manifold for the simultaneous determination of two species in milk samples is reported. Calcium is determined potentiometrically, and, following online sample treatment, spectrophotometric anal. of phosphorus is performed. Results obtained are consistent with manufacturers' estimates and, in the case of calcium, with atomic spectrophotometric measurements. The combination FIA system is a rapid, low-cost, highly reproducible method that uses small sample volumes and could be used to provide on-site near-real-time measurements.
Calcium Phosphorus Cow Spectrophotometry

"Photodiode-based Detector For Monitoring Solution-phase Chemiluminescence"
Spectrosc. Eur. 1994 Volume 6, Issue 5 Pages 19-25
Gachanja, A.;Worsfold, P.J.

Abstract: The use of solid-state photodiode-based detection systems as a reliable low-cost and sensitive alternative to photomultiplier tube-based detection is discussed, with reference to flow injection and LC applications involving the peroxyoxalate chemiluminescence (CL) reaction. The analysis of aliphatic aldehydes and carboxylic acids in used engine oils by pre-column derivatization using fluorescent compounds followed by LC separation and peroxyoxalate CL detection is used to illustrate the efficacy of photodiode-based detectors for monitoring solution-phase CL.
Chemiluminescence LC

"Electrochemical Biosensors For Assays Of L-Malic And D-Lactic Acids In Wines"
Am. J. Enol. Vitic. 1996 Volume 47, Issue 1 Pages 11-16
M. Gilis, H. Durliat, and M. Comtat

Abstract: The knowledge of L-malic acid concentration is important for the follow-up of grape maturation and of malolactic fermentation; in the same way, D- lactic acid concentration gives information about the growth of lactic piqûre. A simple and inexpensive assay method is proposed with the use of amperometric biosensors developed for this specific application. The results are compared to those obtained with the enzymatic spectrophotometric method (Boehringer kit). The difference between the two measurement results shows that colored substances interfere with the compounds assayed in the case of red wine. To minimize this effect, two methods are proposed: a differential measurement or the addition of charcoal to the sample for the adsorption of colored substances. The short response time allows analysis of 100 samples every day, and the biosensor can work for one month with the same enzymatic solution.
l-Malic acid d-Lactic acid Wine Biotechnology Sensor Sensor Spectroelectrochemistry Electrode

"Comparative Study Of Atomic Fluorescence Spectroscopy And Inductively Coupled Plasma Mass Spectrometry For Mercury And Arsenic Multispeciation"
Anal. Bioanal. Chem. 2005 Volume 382, Issue 2 Pages 485-492
Jos&eacute; Luis G&oacute;mez-Ariza, Fernando Lorenzo, Tamara Garc&iacute;a-Barrera

Abstract: Mercury and arsenic are two elements of undoubted importance owing to their toxic character. Although speciation of these elements has been developed separately, in this work for the first time the speciation of As and Hg using two atomic fluorescence detectors in a sequential ensemble is presented. A coupling based on the combination of high-performance liquid chromatography (where mercury and arsenic species are separated) and two atomic fluorescence detectors in series, with several online treatments, including photooxidation (UV) and hydride generation, has allowed the determination of mercury and arsenic compounds simultaneously. The detection limits for this device were 16, 3, 17, 12 and 8 ng mL-1 for As(III), monomethylarsinic acid, As(V), Hg2+ and methylmercury, respectively. This coupling was compared with an analogous one based on inductively coupled plasma-mass spectrometry (ICP-MS) detection, with detection limits of 0.7, 0.5, 0.8, 0.9 and 1.1 ng mL-1, respectively. Multispeciation based on ICP-MS exhibits better sensitivity than the coupling based on tandem atomic fluorescence, but this second device is a very robust system and exhibits obvious advantages related to the low cost of acquisition and maintenance, as well as easy handling, which makes it a suitable system for routine laboratories.
Arsenic Mercury Arsenic(3+) Monomethylarsine Arsenic(5+) Mercury(II) Methylmercury ion Fluorescence HPLC Mass spectrometry