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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Process Control and Quality

  • Publisher:
  • FAD Code: PCQU
  • CODEN: PCQUEJ
  • ISSN: 0924-3089
  • Abbreviation: Process Control Qual.
  • DOI Prefix: 10.1163/1568566
  • Language: English
  • Comments: Fulltext V11 only

Citations 16

"Analytical Options For Control Of Acids And Bases In Hydrometallurgical Processes"
Process Control Qual. 1999 Volume 11, Issue 4 Pages 289-300
Fernando Albertús, Isel Cortés, L.-G. Danielsson and Folke Ingman

Abstract: The most common procedures for the determination of acids and bases in hydrometallurgical process liquors are reviewed and compared. Automated batch titrations, performed by stepwise addition of titrant and using Gran plots for evaluation are reliable but slow compared to flow techniques. Continuous flow titrations are grouped into three classes: Flow Injection Titration, Single Point Flow Injection Titration, and Triangle-programmed Flow Titrations. Furthermore, Sequential Injection Analysis is also considered for process applications. Each one of these methods has advantages and drawbacks. An overview of the most common application problems, and the way they are solved with each methodology, is given. The analytical characteristics of the described procedures are given as well as a guide for the choice of technique for a given application.
Industrial Titrations Sequential injection Review Method comparison

"Determination Of Total Ammonia And Carbon Dioxide In Liquors From The Caron Process For Nickel Extraction"
Process Control Qual. 1996 Volume 8, Issue 4 Pages 185-192
F. Albertús, I. Cortés, L.-G, Danielsson and F. Ingman

Abstract: A 110 µL sample is injected into a carrier stream of water (2.32 ml/min) that then merges with the reagent stream (0.57 ml/min) before passage through a reaction coil (60 cm x 0.5 mm i.d.) and spectrophotometric detection. For the measurement of total alkalinity (NH3 + CO2), the reagent is 0.5 M acetic acid/0.5 M NaNO3/40 µM-bromophenol blue and the absorbance is measured at 592 nm; for the measurement of strong alkalinity (NH3), the reagent is 0.45-0.5 M H3BO3/40 µM-cresol red containing also NaNO3 with measurement at 572 nm. Calibration was effected by non-linear regression. The RSD were 3 and 2.
Ammonia Carbon dioxide Industrial Spectrophotometry Sample preparation Extraction Non-linear regression

"Process Monitoring During Electrochemical Production Of Polysulfides By Online FIA Using A Capillary Flow-through Cell"
Process Control Qual. 1996 Volume 8, Issue 4 Pages 159-166
X.-S. Chai and L.-G. Danielsson

Abstract: We have developed an online flow injection analysis (FIA) method for monitoring sulfur species during electrochemical production of polysulfides. By using a capillary flow-through cell, we can reduce the dilution of the sample and the influence from oxygen dissolved in the diluent can be minimised. 11 References Diagrams are presented of the FIA manifold, showing the way in which it is connected to the electrolysis unit, of the modified Rheodyne 7040 injector (sample volume 1 µl), and of the capillary cell for the spectrophotometric detector. Use of this system minimizes dilution of the sample and the effects of dissolved O2. The absorbance of polysulfides in the region 340-400 nm increases with chain length. By detection at 360 nm it was possible to detect the secondary formation of long-chain polysulfide in a side-reaction.
Sulfur compounds Spectrophotometry Process monitoring Flowcell Interferences

"Direct Analysis Of Organic-compounds In Water By Membrane Introduction Mass-spectrometry Advances In Selectivity And Interfaces"
Process Control Qual. 1995 Volume 7, Issue 3-4 Pages 117-131
J.S. Patrick, P. Wong, C. Xu, M. Soni, N. Kasthurikrishnan, N. Srinivasan and R.G. Cooks

Abstract: An overview of recent advances in membrane introduction mass spectrometry (MIMS) is presented. Particular attention is given to developments in interfaces, improvements in sensitivity and enhancements in selectivity. A new interface is employed which uses pneumatically assisted transport of the analyte to a jet separator interfaced to a benchtop ion trap mass spectrometer. Affinity MIMS, a new experiment which allows selective trapping of analytes (here benzaldehydes) at a chemically modified membrane, is described. Extended loading times followed by release using a chemical agent yields a limit of detection of 10 ppb for benzaldehyde. Notched broad-band excitation using stored waveform inverse Fourier transform (SWIFT) experiments on a benchtop ion trap is also used to enhance selectivity by permitting injection or retention of selected ions within the ion trap. The combination of SWIFT, signal averaging and extended ionization times has allowed the detection of trans-dichloroethene and toluene at 500 parts-per-quadrillion levels in water with no sample pre-concentration. Tandem mass spectrometry of analytes, introduced by MIMS, is also performed using SWIFT on the benchtop ion trap instrument. Both unimolecular dissociations and ion/molecule reactions can be used to characterize analytes. Trace level(10 ppb) analysis of volatile organics in a seawater matrix is described using flow injection sample handling; the matrix causes no changes in permeation rate or detector response relative to an aqueous solution. Methods are discussed for the detection of glycerol and 5-hydroxymethylfurfuraldehyde, a dehydration product of glucose, using MIMS. Finally, information acquired by MIMS is used to provide feedback control of a yeast fermentation. Each of these advances in MIMS finds application in online monitoring of chemical process streams. (52 references)
Organic compounds Fermentation broth Sea Mass spectrometry Interface Membrane Process control Fourier transform Review PPQ Preconcentration

"Automated Measurement Of Aqueous Ozone Concentration"
Process Control Qual. 1995 Volume 6, Issue 4 Pages 229-243
J.L. Darby, D.P.Y. Chang, P.S. Coggin, H.K. Chung and P.K. Dasgupta

Abstract: Three previously described systems (Dasgupta et al. Am. Water Works Assoc. Research Foundation Report, 1993) namely a FIA system, a gas permeation membrane-based device and a nebulizer-based system, for the automated measurement of aqueous ozone were evaluated in field tests. Total dissolved solids, oxidizable organic matter and suspended solids seriously affected the performance of the membrane and nebulizer-based systems. The dual detector FIA system was simple, fast and efficient with detection limits of 10^-20 µg/l. The effects of interferences are discussed.
Ozone Environmental Gas diffusion Membrane Interferences Dissolved solids

"Status Of Process Flow Injection Analysis And Current Trends"
Process Control Qual. 1994 Volume 6, Issue 2-3 Pages 91-95
E.D. Yalvac and R.A. Bredeweg

Abstract: The status of process FIA is presented and the maintenance issue is discussed. Miniaturization is reviewed, with an example application illustrating the determination of total alkalinity by flow-injection titration technique. (14 references).
Alkalinity, total Review Process control Miniaturization Titrations

"New Flow Injection Analyser For Monitoring Trace Hydrogen Cyanide In Process Gas Streams"
Process Control Qual. 1994 Volume 5, Issue 4 Pages 259-265
D.C. Olson, S.R. Bysouth, P.K. Dasgupta and V. Kuban

Abstract: The analyzer. is shown diagramatically. The FIA manifold is a three-stream configuration. The main stream comprising a caustic solution flowed through a gas-permeation unit (GPU) which acted as the sample loop. The HCN permeated the walls of the silicane tubing and was collected into the caustic solution The HCN concentrations became enriched before being flushed from the GPU and merging with a buffered chloramine-T stream and then with a buffered reagent mixture of isonicotinic acid and 3-methyl-1-phenyl-2-pyrazalin-5-one. The intensely colored purple product formed was measured at 630 nm in an optical cell. A pH cell downstream from the detector was used for pH monitoring as the system is pH sensitive with an optimum response in the pH range from 6.5-7.3. The flow rates are given. The system was capable of measuring from low ppb to high ppm levels of HCN in gas streams in the presence of at least 5000 ppm of H2S. The method may be used for other gases such as H2S, CO2, SO2 and NH3.
Hydrogen cyanide Gas Spectrophotometry Gas diffusion Optimization Process monitoring Silicone tubing

"Evaluation Of Direct Versus Competitive Binding Assays In Flow Injection Systems"
Process Control Qual. 1992 Volume 4, Issue 1 Pages 37-45
M. Nilsson, H. Håkanson and B. Mattiasson

Abstract: A small column of immobilized concanavalin A was place in a FIA system and used to carry out direct and indirect binding analyzes using horseradish peroxidase. In the latter type of assay, addition of a free carbohydrate, methyl αD-mannopyranoside, provided the competitive binding situation. The direct binding assays gave straight calibration curves and good fits in gradient experiments. The competitive assay gave more complex calibration curves with more complex data evaluation and less precision at higher concentrations. When suitable it is more straightforward to utilize a direct binding assay for process control in the production of enzymes.
Immobilized enzyme Gradient technique Process control

"Operational Parameters Affecting Zone Penetration In Sequential Injection Analysis"
Process Control Qual. 1992 Volume 3, Issue 1-4 Pages 251-261
G.D. Marshall and J.F. van Staden

Abstract: An introductory outline to sequential injection analysis (SIA) is presented. Design factors affecting the optimum performance of SIA systems are investigated. Four factors are considered: tube diameter, reaction coil geometry, pump speed and selection order. By using solutions of bromothymol blue dye and sodium tetraborate carrier it was shown that: (i) when a tube diameter of 0.8 mm or 1.5 mm was used, improved precision was attained without an excessive decrease in zone penetration; (ii) straight reaction coils allowed greater zone penetration; (iii) faster pump speeds allowed shorter analysis times; (iv) greater dispersion was observed in the first zone selected.
Bromothymol blue Spectrophotometry Sequential injection Zone penetrating Theory

"Determination Of Cyanide Using A Simple And Versatile Process Analyser"
Process Control Qual. 1992 Volume 3, Issue 1-4 Pages 173-183
M.J.C. Taylor, D.E. Barnes, G.D. Marshall, D.R. Groot and S.J.S. Williams

Abstract: The monitoring of available cyanide in the leaching and adsorption circuits of Au extraction plants is important to reduce cyanide consumption while ensuring efficient Au recovery. The development of a robust and compact process cyanide analyzer. from a bulky laboratory version is described. The detector cell consisted of a cyanide-selective AgI - Ag2S electrode and a miniaturized Ag - AgCl reference electrode and was used in conjunction with a sequential injection manifold. Filtered sample solution and carrier solution (19 mM sodium carbonate - 5 mM sodium hydrogen borate - 22 µM-ethylenediamine - 2.5 mg L-1 CN-) were drawn into a holding tube and the mixture was transferred to the detector cell. Free cyanide was determined in the range 1 to 200 mg L-1 with a detection limit of 0.5 mg L-1 and a coefficient of variation of 0.028 at 100 mg l-1. The sampling frequency was 45 h-1.
Cyanide Process liquor Electrode Electrode Process monitoring Sequential injection

"Sequential Injection Methodology For Fermentation Monitoring"
Process Control Qual. 1992 Volume 3, Issue 1-4 Pages 115-125
S.C. Chung, G.D. Christian and J. Ruzicka

Abstract: Sequential injection methodology was developed for the online monitoring of glucose during a yeast fermentation. The glucose assay was based on the Trinder reaction; standard glucose solution were used for calibration. The analyzer. consisted of a sinusoidal piston pump, a single multi-port selection valve and a detector. By the appropriate switching of the valve, a single stroke of the piston drew 2 mL of deionized water as carrier, 400 µL of Trinder reagent and 50 µL of sample solution into the holding conduit. The piston then moved in the reverse direction to transfer the solution to the detector cell of the spectrophotometer. The flow of liquid was stopped for 30 s while the absorbance at 504 nm was monitored. From the results, the rate of reaction and hence the concentration. of glucose was calculated. The calibration graph for glucose was rectilinear from 0.04 to 0.4 g l-1.
Glucose Fermentation broth Spectrophotometry Sequential injection Optimization

"Online Monitoring Of Microbial Processes By Flow Injection Analysis"
Process Control Qual. 1992 Volume 2, Issue 4 Pages 371-384
J. Nielsen

Abstract: The application of flow injection analysis in biotechnological analysis is described and different sampling methods are discussed.
Fermentation broth Process monitoring

"Comparison Of Flow Injection Methods For Determination Of Abietic Acid"
Process Control Qual. 1992 Volume 2, Issue 4 Pages 305-320
M.D. Kester, J.A. Horner, H. Nicolidakis, A.P. Wade and J.T. Wearing

Abstract: The spectrophotometric method for resin acid determination as used by Carpenter, (TAPPI, 1965, 48, 669) was automated using flow injection for the analysis of abietic acid (I; liberated during the production of wood pulp). The reaction of I with H2SO4 and acetic anhydride resulted in a transient pink compound which was measured at 518 nm. The flow-through cell provided a sample throughput of 30 h-1. The detection limit was 20 mg L-1 of I and coefficient of variation was 6.3% (n = 10) at 500 mg. The calibration graph was rectilinear from 20 to 1000 mg L-1 of I. The method can be used by semi-skilled operators and required 1 mL of each reagent per analysis, which greatly minimizes human interaction with potentially dangerous chemicals.
Abietic acid Pulp Process liquor Spectrophotometry Method comparison

"Robust Photometric Detector For Process Analysis"
Process Control Qual. 1992 Volume 2, Issue 3 Pages 249-255
G.D. Marshall, M.J.C. Taylor, D.E. Barnes and S.J.S. Williams

Abstract: The instrument described and illustrated incorporates a light-emitting diode, a transmitter to modulate the light output and a receiver to detect the modulated light. Two flow cells are used; one is formed by drilling a hole (1.1 mm diameter) through the body of the diode, and the other, of Z-shaped design, has a diameter of 0.5 mm. The apparatus has been used in a flow injection arrangement for the determination of V in samples from a solvent extraction V purification plant; ascorbic acid in 1% H2SO4 is used as carrier stream to reduce V(V) to V(IV), which is determined at 760 nm. The Z-shaped cell is subject to refractive index effects, which can be overcome by matrix matching or blank subtraction. Results obtained with the analyzer agreed with those of redox titration.
Vanadium Industrial Spectrophotometry Process monitoring Light emitting diode Flowcell Refractive index Method comparison

"Implementation Of Flow Injection Titration Technique Based On The CAMILE Data Acquisition And Control System"
Process Control Qual. 1992 Volume 2, Issue 3 Pages 215-224
W.A. Heeschen, D.C. Greminger and E.D. Yalvac

Abstract: For the determination of strong and weak acids, a product stream is sampled by a pneumatically actuated six-port valve, and a portion (80.4 µL) is injected into a titrant stream of aqueous 0.01 M NaOH. The solution passes to a 1 mL mixing cell fitted with an ISI pH electrode connected to a Cole-Parmer pH transmitter. The equipment is connected and controlled by a CAMILE 3000 and Compaq DeskPro 386 computer running version 11 of the CAMILE software, by means of which the Savitzky-Golay algorithm is implemented for data smoothing and differentiation to detection the inflection points. The logic flow diagram of the system is presented. Calibration is effected with stable and standards modelling those in the product stream. In the titration of binary mixtures of strong and weak acids (or, with an acidic titrant stream, strong and weak bases), the pKa values should differ by at least 5 units; the strong species is titrated first.
Acids, weak Acids, strong Electrode Potentiometry Computer Titrations Data acquisition Digital filter Process control

"Bioreactor Monitoring Using Flow Injection - Membrane-introduction Mass Spectrometry With An Ion-trap Detector"
Process Control Qual. 1991 Volume 1, Issue 2 Pages 105-116
M.J. Hayward, D.E. Riederer, T. Kotiaho, R.G. Cooks, G.D. Austin, M.-J. Syu and G.T. Tsao

Abstract: Plugs (250 µL) of the fermentation broth were injected into a stream (1 mL min-1) of water, followed after 2 min by a plug of standard solution The flow injection system delivered the sample and standard to a special membrane probe (described with diagram) to introduce analytes into an ion-trap mass spectrometer. The major liquid phase products (e.g., butane-2,3-diol, acetoin, acetic acid and ethanol) were monitored by scanning from m/e 45 to 95 by water CI at 20 µTorr. The monitoring sequence was consecutive plugs of fermentation broth, standard, broth acidified with 0.1 M HCl (1:1) and acidified standard and monitoring at m/e 47, 61, 73 and 89. Acidification was required for acetic acid to permeate the membrane.
2,3-dihydroxybutane Acetoin Acetic acid Ethanol Fermentation broth Mass spectrometry Mass spectrometry Membrane