Dispersion in open tubular reactors of various geometries

Waiz, Saif; Cedillo, Bertha M; Jambunathan, Sivakumar; Hohnholt, Sofia G; Dasgupta, Purnendu Κ.; Wolcott, Duane K.

doi:10.1016/s0003-2670(00)01230-7

Cited by 38 publications

(31 citation statements)

References 13 publications

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“…coil and 0.46 mm i. d. tubing in the superserpentine II (SS2) design [38]. The difference was not marked; there was also little dependence on the MC length (Figure S5) suggesting that the arrow mixer already achieves good mixing and the reaction is fast.…”

Section: Resultsmentioning

confidence: 99%

Cobinamide chemistries for photometric cyanide determination. A merging zone liquid core waveguide cyanide analyzer using cyanoaquacobinamide

Dasgupta

Zelder

et al. 2012

Analytica Chimica Acta

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Diaquacobinamide (H2O)2Cbi2+ or its conjugate base hydroxyaquacobinamide (OH(H2O)Cbi+)) can bind up to two cyanide ions, making dicyanocobinamide. This transition is accompanied by a significant change in color, previously exploited for cyanide determination. The reagent OH(H2O)Cbi+ is used in excess; when trace amounts of cyanide are added, CN(H2O)Cbi+ should be formed. But the spectral absorption of CN(H2O)Cbi+ is virtually the same as that of OH(H2O)Cbi+. It has been inexplicable how trace amounts of cyanide are sensitively measured by this reaction. It is shown here that even with excess OH(H2O)Cbi+, (CN)2Cbi is formed first due to kinetic reasons; this only slowly forms CN(H2O)Cbi+. This understanding implies that CN(H2O)Cbi+ will itself be a better reagent. We describe a single valve merging zone flow analyzer that allows both sample and reagent economy. With a 50 cm liquid core waveguide (LCW) flow cell and an inexpensive fiber optic - charge coupled device array spectrometer, a S/N=3 limit of detection of 8 nM, a linear dynamic range to 6 μM, and excellent precision (RSD 0.49% and 1.07% at 50 and 100 nM, respectively, n=5 each) are formed. At 1% carryover, sample throughput is 40 h−1. The setup is readily used to measure thiocyanate with different reagents. We demonstrate applicability to real samples by analyzing human saliva samples and hydrolyzed extracts of apple seeds, peach pits, and almonds.

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Section: Resultsmentioning

confidence: 99%

Cobinamide chemistries for photometric cyanide determination. A merging zone liquid core waveguide cyanide analyzer using cyanoaquacobinamide

Dasgupta

Zelder

et al. 2012

Analytica Chimica Acta

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“…In this con®guration, the¯ow follows a series of turns that interrupt growth of the boundary layer repetitively and keep its size minimal. This decreases both dispersion (Curtis and Shahwan, 1988;Waiz et al, 2001) and the resistance to mass and heat transfer (Choi and Anand, 1995;Choi et al, 1996;Kalb and Seader, 1972;Mochizuki, 1999;Snyder et al, 1993;Tanishita et al, 1991). The BioScope consists of 20 serpentine units between which 11 sampling ports are located.…”

Section: Description Of the Sampling Systemmentioning

confidence: 99%

Rapid sampling for analysis of in vivo kinetics using the BioScope: A system for continuous‐pulse experiments

Visser¹,

Zuylen²,

Dam³

et al. 2002

Biotech & Bioengineering

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In this article we present a novel device, the BioScope, which allows elucidation of in vivo kinetics of microbial metabolism via perturbation experiments. The perturbations are carried out according to the continuous-flow method. The BioScope consists of oxygen permeable silicon tubing, connected to the fermentor, through which the broth flows at constant velocity. The tubing has a special geometry (serpentine channel) to ensure plug flow. After leaving the fermentor, the broth is mixed with a small flow of perturbing agent. This represents the start of the perturbation. The broth is sampled at different locations along the tubing, corresponding to different incubation times. The maximal incubation time is 69 s; the minimally possible time interval between the samples is 3-4 s. Compared to conventional approaches, in which the perturbation is carried out in the fermentor, the BioScope offers a number of advantages. (1) A large number of different perturbation experiments can be carried out on the same day, because the physiological state of the fermentor is not perturbed. (2) In vivo kinetics during fed-batch experiments and in large-scale reactors can be investigated. (3) All metabolites of interest can be measured using samples obtained in a single experiment, because the volume of the samples is unlimited. (4) The amount of perturbing agent spent is minimal, because only a small volume of broth is perturbed. (5) The system is completely automated. Several system properties, including plug-flow characteristics, mixing, oxygen and carbon dioxide transfer rates, the quenching time, and the reproducibility have been explored, with satisfactory results. Responses of several glycolytic intermediates in Saccharomyces cerevisiae to a glucose pulse, measured using a conventional approach are compared to results obtained with the BioScope. The agreement between the results demonstrates that the BioScope is indeed a promising device for studying in vivo kinetics.

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“…The tortuous path of the serpentine mixer causes in-line mixing to occur 43–45 . For the column mixer, the two liquids were delivered to the column of glass beads, thus creating intensively mixed phases as they were driven through the bed of small spheres.…”

Section: Methodsmentioning

confidence: 99%

Development of an autonomous solvent extraction system to isolate astatine-211 from dissolved cyclotron bombarded bismuth targets

O’Hara

Krzysko

Hamlin

et al. 2019

Sci Rep

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Cyclotron-produced astatine-211 (211At) shows tremendous promise in targeted alpha therapy (TAT) applications due to its attractive half-life and its 100% α-emission from nearly simultaneous branched alpha decay. Astatine-211 is produced by alpha beam bombardment of naturally monoisotopic bismuth metal (209Bi) via the (α, 2n) reaction. In order to isolate the small mass of 211At (specific activity = 76 GBq·µg−1) from several grams of acid-dissolved Bi metal, a manual milliliter-scale solvent extraction process using diisopropyl ether (DIPE) is routinely performed at the University of Washington. As this process is complex and time consuming, we have developed a fluidic workstation that can perform the method autonomously. The workstation employs two pumps to concurrently deliver the aqueous and organic phases to a mixing tee and in-line phase mixer. The mixed phases are routed to a phase settling reservoir, where they gravity settle. Finally, each respective phase is withdrawn into its respective pump. However, development of a phase boundary sensor, placed in tandem with the phase settling reservoir, was necessary to communicate to the system when withdrawal of the denser aqueous phase was complete (i.e., the intersection of the two phases was located). The development and optimization of the autonomous solvent extraction system is described, and the 211At yields from several ~1.1 GBq-level 211At processing runs are reported.

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Dispersion in open tubular reactors of various geometries

Cited by 38 publications

References 13 publications

Cobinamide chemistries for photometric cyanide determination. A merging zone liquid core waveguide cyanide analyzer using cyanoaquacobinamide

Cobinamide chemistries for photometric cyanide determination. A merging zone liquid core waveguide cyanide analyzer using cyanoaquacobinamide

Rapid sampling for analysis of in vivo kinetics using the BioScope: A system for continuous‐pulse experiments

Development of an autonomous solvent extraction system to isolate astatine-211 from dissolved cyclotron bombarded bismuth targets

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