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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Zone penetrating

Classification: Manifold process -> Zone penetrating

Citations 7

"Comparison Of Three Propulsion Systems For Application In Flow Injection Zone Penetration Dilution And Sorbent Extraction Preconcentration For Flame Atomic Absorption Spectrometry"
Anal. Chim. Acta 1992 Volume 269, Issue 1 Pages 9-19
Zhao-Lun Fang, Michael Sperling and Bernhard Welz*

Abstract: The zone penetration technique (Zagatto, Ibid., 1985, 173, 289) was evaluated using a peristaltic pump, a reciprocating piston pump and a sinusoidal syringe pump as propulsion systems in conjunction with an online sorbent extraction system. The efficiency of the dilution and the performance of pre-concentration with flame AAS detection were examined. Performance of the peristaltic pump was equal or better than that of the others which only showed superiority in improved long-term stability. Better precision can be achieved in flow injection online dilution for flame atomic absorption spectrometry by zone penetration using knotted reactor sample loops and transport conduits than with straight conduits. About a 2% relative standard deviation (RSD) was obtained for a dilution factor of 20 using the valley between 2 peaks with a peristaltic and a reciprocating piston pump. A sinusoidal syringe pump gave an inferior precision of 8% RSD under the same conditions owing to a lack of proper interfacing between such pumps and the atomic absorption spectrometer. Online sorbent extraction column pre-concentration. is feasible using sinusoidal and reciprocating pump systems, which obviated the need for solvent-proof pump tubes. However, both systems had to be supplemented by peristaltic pumps. Air segmentation between sample and eluent is effective in preventing dispersion at the interface when sample loading and elution were performed in 1 piston stroke of the sinusoidal pump. The concentration. efficiency (15-18 min-1) and short-term precision (~2% RSD) of both pre-concentration. systems were generally comparable to those of previously reported systems for sorbent extraction pre-concentration. with time-based sampling, but the long-term precision of the piston and syringe pump systems (4-5% RSD) was better than that of the time-based peristaltic pump system (10-20% RSD).
Spectrophotometry Sample preparation

"Use Of A Sequential Injection Technique To Evaluate The Effect Of Mixing Chambers On Zone Penetration"
Anal. Chim. Acta 1998 Volume 367, Issue 1-3 Pages 111-121
T. McCormack and J. F. van Staden*

Abstract: The simple chemical and fast rate of the complexation reaction between tiron and iron(III) were used to evaluate the effect four mixing chambers of various volumes (1.2-4.0 mL) have on the degree and reproducibility of zone penetration within a sequential injection (SI) system. As a consequence of this study a fully computerized SI system for the spectrophotometric determination of iron(III) in mine waters is proposed. Using a 1.2 mL mixing chamber placed before the detector, the method is able to analyze 24 samples per h with an average relative standard deviation of 0.28%. The calibration graph is linear between 0 and 200 mg/L with a 3s detection limit of 0.03 mg/L.
Iron(III) Mine Spectrophotometry

"Double-injection Flow Injection Analysis Using Multivariate Calibration For Multi-component Analysis"
Anal. Chem. 1991 Volume 63, Issue 8 Pages 775-781
David A. Whitman, Mary Beth Seasholtz, Gary D. Christian, Jarda Ruzicka, and Bruce R. Kowalski

Abstract: The flow injection system described is based on the zone penetration technique (cf. Ruzicka and Hansen, Flow injection Analysis, 2nd edition Wiley and Sons, 1988, 63 and 258) and involves simultaneous injection of sample and reagent in a single flow line. Double injection was performed by use of a simple 8-port value wherein the sample occupied the leading injection loop and the reagent the second one. The analytes yielded overlapping but different concentration. profiles along the time axis and these were analyzed by multivariate calibration methods based on partial least-squares or principal component regression. Application of the method is illustrated by the simultaneous determination of Fe and Ni in a model plating bath solution Nickel was determined via its green aquo species whilst Fe was determined as its Fe(III)-SCN- complex. The proposed method uses only one-eight of the sample and reagent required for the single injection procedure described previously (cf. Anal. Chim. Acta, 1988, 214, 197).
Iron Nickel 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

"Efficient Flow Injection Online Dilution System For Flame Atomic Absorption Spectrometry Based On Micro-zone Penetration"
Microchem. J. 1994 Volume 50, Issue 2 Pages 145-150
Xu S. K. and Fang Z. L.

Abstract: Combination of microsampling dilution with zone penetration produced an efficient automated dilution system for flame AAS capable of direct determination of Na, K and alkaline-earth metals in samples containing several g/l of the analytes. The highest dilution factor attained was 27 000 but values of 50 000 might be possible using updated software. Sampling frequency was 45/h and RSD were better than 2%. A drawback is that readouts have to be made manually on the recordings. The system was applied to the determination of Mg in brines used in bean curd production.
Sodium Potassium Metals, alkaline earth Magnesium Environmental Spectrophotometry

"Recent Advances In Flow Injection Analysis"
Int. Lab. 1985 Volume 15, Issue 8 Pages 14-23
Hansen, E.H.

Abstract: A review is presented, in which the development of flow injection analysis and the use of gradient dilution, gradient calibration, stopped-flow, gradient scanning, titrations, penetrating zones and other techniques with flow injection analysis are discussed. (18 references).

"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