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Modern Flow Analysis
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Modern Flow Analysis

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Analytical Chemistry".

Deadline for manuscript submissions: closed (29 February 2020) | Viewed by 45647

Printed Edition Available!
A printed edition of this Special Issue is available here.

Special Issue Editor

Prof. Dr. Pawel Koscielniak

E-Mail Website
Guest Editor
Department of Analytical Chemistry, Faculty of Chemistry, Jagiellonian University in Kraków, Gronostajowa St. 2, 30-387 Kraków, Poland
Interests: flow analysis; forensic chemistry; environmental chemistry; green analysis; analytical calibration; interference effects; optimization methods
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Flow analysis (FA), invented successfully in the middle of 1950s, is a well-recognized and systematically developed branch of analytical chemistry. In FA systems, the analyzed sample can be processed through various physicochemical operations, including extraction, preconcentration or transformation into a chemical form most suitable for the detection used. The flow mode allows a sample to be prepared in a fast, low-cost, safe and efficient way. In addition, due to the mechanization and automation of FA processes, the final analytical results are as a rule more reliable than those obtained under non-flow conditions.

For years, special interest has been focused on instrumental progress in FA. It has been proved that samples can be efficiently treated not only in the continuous flow mode but also in the form of individual segments injected to the carrier stream. In order to decrease the sample and reagent consumption, the concepts of multisyringe and multicommutated flow systems have been introduced into analytical practice. Advances in the field of new materials have been used, amongst other things, to construct original modern detectors dedicated to measurements in the flow mode.

The last FA developments are characterized by specific features that are oriented, in general, towards “green” analytical chemistry. For instance, the gradient technique—based on the idea that the particular points of a single injection peak can be a sufficiently rich source of analytical information—is again noticed and applied. Different micro-extraction liquid–liquid and solid–liquid techniques have been ingeniously adapted to flow conditions, making possible operation with a sample drop. The tendency to make flow systems miniaturized and integrated is expressed by lab-on-valve (LOV) devices, which work sequentially to process a sample in different ways with micro-volumes of reagents. In addition, low-cost flow systems are increasingly designed using either 3D-printing technology or using paper as a body of liquid movement in lab-on-paper (LOP) devices.

I warmly invite members of the “flow family” to submit their original contributions to this Special Issue in order to present the above (and additional) modern aspects of flow analysis with special attention to those that make analytical procedures more environmentally safe and friendly.

We would be delighted if you could respond to confirm your contribution and the proposed title by 31 October 2019.

Prof. Dr. Pawel Koscielniak
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • micro-extraction techniques
  • separation and preconcentration techniques
  • miniaturized flow systems
  • LOV systems
  • LOP systems
  • gradient technique
  • natural reagents
  • one-standard calibration procedures
  • flow titration
  • flow detectors

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Published Papers (14 papers)

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Editorial

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5 pages, 173 KiB  
Editorial
Modern Flow Analysis
by Paweł Kościelniak
Molecules 2020, 25(12), 2897; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25122897 - 24 Jun 2020
Cited by 2 | Viewed by 1756
Abstract
A brief overview of articles published in this Special Issue of Molecules titled “Modern Flow Analysis” is provided. In addition to cross-sectional and methodological works, there are some reports on new technical and instrumental achievements. It has been shown that all these papers [...] Read more.
A brief overview of articles published in this Special Issue of Molecules titled “Modern Flow Analysis” is provided. In addition to cross-sectional and methodological works, there are some reports on new technical and instrumental achievements. It has been shown that all these papers create a good picture of contemporary flow analysis, revealing the most current trends and problems in this branch of flow chemistry. Full article
(This article belongs to the Special Issue Modern Flow Analysis)

Research

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14 pages, 2394 KiB  
Article
Dual-Purpose Photometric-Conductivity Detector for Simultaneous and Sequential Measurements in Flow Analysis
by Thitirat Mantim, Korbua Chaisiwamongkhol, Kanchana Uraisin, Peter C. Hauser, Prapin Wilairat and Duangjai Nacapricha
Molecules 2020, 25(10), 2284; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25102284 - 13 May 2020
Cited by 6 | Viewed by 2550
Abstract
This work presents a new dual-purpose detector for photometric and conductivity measurements in flow-based analysis. The photometric detector is a paired emitter–detector diode (PEDD) device, whilst the conductivity detection employs a capacitively coupled contactless conductivity detector (C4D). The flow-through detection cell is a [...] Read more.
This work presents a new dual-purpose detector for photometric and conductivity measurements in flow-based analysis. The photometric detector is a paired emitter–detector diode (PEDD) device, whilst the conductivity detection employs a capacitively coupled contactless conductivity detector (C4D). The flow-through detection cell is a rectangular acrylic block (ca. 2 × 2 × 1.5 cm) with cylindrical channels in Z-configuration. For the PEDD detector, the LED light source and detector are installed inside the acrylic block. The two electrodes of the C4D are silver conducting ink painted on the PEEK inlet and outlet tubing of the Z-flow cell. The dual-purpose detector is coupled with a sequential injection analysis (SIA) system for simultaneous detection of the absorbance of the orange dye and conductivity of the dissolved oral rehydration salt powder. The detector was also used for sequential measurements of creatinine and the conductivity of human urine samples. The creatinine analysis is based on colorimetric detection of the Jaffé reaction using the PEDD detector, and the conductivity of the urine, as measured by the C4D detector, is expressed in millisiemens (mS cm−1). Full article
(This article belongs to the Special Issue Modern Flow Analysis)
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13 pages, 1663 KiB  
Article
Novel Approach to Sample Preconcentration by Solvent Evaporation in Flow Analysis
by Justyna Paluch, Joanna Kozak, Marcin Wieczorek, Michał Woźniakiewicz, Małgorzata Gołąb, Ewelina Półtorak, Sławomir Kalinowski and Paweł Kościelniak
Molecules 2020, 25(8), 1886; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25081886 - 18 Apr 2020
Cited by 6 | Viewed by 2559
Abstract
A preconcentration module operated in flow mode and integrated with a sequential injection system with spectrophotometric detection was developed. Using the system, preconcentration was performed in continuous mode and was based on a membraneless evaporation process under diminished pressure. The parameters of the [...] Read more.
A preconcentration module operated in flow mode and integrated with a sequential injection system with spectrophotometric detection was developed. Using the system, preconcentration was performed in continuous mode and was based on a membraneless evaporation process under diminished pressure. The parameters of the proposed system were optimized and the system was tested on the example of the spectrophotometric determination of Cr(III). The preconcentration effectiveness was determined using the signal enhancement factor. In the optimized conditions for Cr(III), it was possible to obtain the signal enhancement factors of around 10 (SD: 0.9, n = 4) and determine Cr(III) with precision and intermediate precision of 8.4 and 5.1% (CV), respectively. Depending on the initial sample volume, signal enhancement factor values of about 20 were achieved. Applicability of the developed preconcentration system was verified in combination with the capillary electrophoresis method with spectrophotometric detection on the example of determination of Zn in certified reference materials of drinking water and wastewater. Taking into account the enhancement factor of 10, a detection limit of 0.025 mg L−1 was obtained for Zn determination. Zn was determined with precision less than 6% (CV) and the results were consistent with the certified values. Full article
(This article belongs to the Special Issue Modern Flow Analysis)
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13 pages, 2357 KiB  
Article
Development of a Simple Reversible-Flow Method for Preparation of Micron-Size Chitosan-Cu(II) Catalyst Particles and Their Testing of Activity
by Apichai Intanin, Prawpan Inpota, Threeraphat Chutimasakul, Jonggol Tantirungrotechai, Prapin Wilairat and Rattikan Chantiwas
Molecules 2020, 25(8), 1798; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25081798 - 14 Apr 2020
Cited by 4 | Viewed by 2353
Abstract
A simple flow system employing a reversible-flow syringe pump was employed to synthesize uniform micron-size particles of chitosan-Cu(II) (CS-Cu(II)) catalyst. A solution of chitosan and Cu(II) salt was drawn into a holding coil via a 3-way switching valve and then slowly pumped to [...] Read more.
A simple flow system employing a reversible-flow syringe pump was employed to synthesize uniform micron-size particles of chitosan-Cu(II) (CS-Cu(II)) catalyst. A solution of chitosan and Cu(II) salt was drawn into a holding coil via a 3-way switching valve and then slowly pumped to drip into an alkaline solution to form of hydrogel droplets. The droplets were washed and dried to obtain the catalyst particles. Manual addition into the alkaline solution or employment of flow system with a vibrating rod, through which the end of the flow line is inserted, was investigated for comparison. A sampling method was selected to obtain representative samples of the population of the synthesized particles for size measurement using optical microscopy. The mean sizes of the particles were 880 ± 70 µm, 780 ± 20 µm, and 180 ± 30 µm for the manual and flow methods, without and with the vibrating rod, respectively. Performance of the flow methods, in terms of rate of droplet production and particle size distribution, are discussed. Samples of 180 µm size CS-Cu(II) particles were tested for catalytic reduction of 0.5 mM p-nitrophenol to p-aminophenol by 100-fold excess borohydride. The conversion was 98% after 20 min, whereas without the catalyst there was only 14% conversion. Full article
(This article belongs to the Special Issue Modern Flow Analysis)
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11 pages, 1581 KiB  
Article
Determination of Albumin, Glucose, and Creatinine Employing a Single Sequential Injection Lab-at-Valve with Mono-Segmented Flow System Enabling In-Line Dilution, In-Line Single-Standard Calibration, and In-Line Standard Addition
by Kanokwan Kiwfo, Wasin Wongwilai, Tadao Sakai, Norio Teshima and Kate Grudpan
Molecules 2020, 25(7), 1666; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25071666 - 04 Apr 2020
Cited by 7 | Viewed by 2634
Abstract
A mono-segmented sequential injection lab-at-valve (SI-LAV) system for the determination of albumin, glucose, and creatinine, three key biomarkers in diabetes screening and diagnosis, was developed as a single system for multi-analyte analysis. The mono-segmentation technique was employed for in-line dilution, in-line single-standard calibration, [...] Read more.
A mono-segmented sequential injection lab-at-valve (SI-LAV) system for the determination of albumin, glucose, and creatinine, three key biomarkers in diabetes screening and diagnosis, was developed as a single system for multi-analyte analysis. The mono-segmentation technique was employed for in-line dilution, in-line single-standard calibration, and in-line standard addition. This made adjustments to the sample preparation step easy unlike the batch-wise method. The results showed that the system could be used for both fast reaction (albumin) and slow reaction (glucose with enzymatic reaction and creatinine). In the case of slow reaction, the analysis time could be shortened by using the reaction rate obtained with the SI-LAV system. This proposed system is for cost-effective and downscaling analysis, which would be applicable for small hospitals and clinics in remote places with a small number of samples but relatively fast screening would be needed. Full article
(This article belongs to the Special Issue Modern Flow Analysis)
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11 pages, 995 KiB  
Article
Fluorimetric Method for the Determination of Histidine in Random Human Urine Based on Zone Fluidics
by Antonios Alevridis, Apostolia Tsiasioti, Constantinos K. Zacharis and Paraskevas D. Tzanavaras
Molecules 2020, 25(7), 1665; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25071665 - 04 Apr 2020
Cited by 18 | Viewed by 2233
Abstract
In the present study, the determination of histidine (HIS) by an on-line flow method based on the concept of zone fluidics is reported. HIS reacts fast with o-phthalaldehyde at a mildly basic medium (pH 7.5) and in the absence of additional nucleophilic [...] Read more.
In the present study, the determination of histidine (HIS) by an on-line flow method based on the concept of zone fluidics is reported. HIS reacts fast with o-phthalaldehyde at a mildly basic medium (pH 7.5) and in the absence of additional nucleophilic compounds to yield a highly fluorescent derivative (λex/λem = 360/440 nm). The flow procedure was optimized and validated, paying special attention to its selectivity and sensitivity. The LOD was 31 nmol·L−1, while the within-day and day-to-day precisions were better than 1.0% and 5.0%, respectively (n = 6). Random urine samples from adult volunteers (n = 7) were successfully analyzed without matrix effect (<1%). Endogenous HIS content ranged between 116 and 1527 μmol·L−1 with percentage recoveries in the range of 87.6%–95.4%. Full article
(This article belongs to the Special Issue Modern Flow Analysis)
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12 pages, 839 KiB  
Article
Novel Approach to Automated Flow Titration for the Determination of Fe(III)
by Joanna Kozak, Justyna Paluch, Marek Kozak, Marta Duracz, Marcin Wieczorek and Paweł Kościelniak
Molecules 2020, 25(7), 1533; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25071533 - 27 Mar 2020
Cited by 6 | Viewed by 3413
Abstract
A novel approach to automated flow titration with spectrophotometric detection for the determination of Fe(III) is presented. The approach is based on the possibility of strict and simultaneous control of the flow rates of sample and titrant streams over time. It consists of [...] Read more.
A novel approach to automated flow titration with spectrophotometric detection for the determination of Fe(III) is presented. The approach is based on the possibility of strict and simultaneous control of the flow rates of sample and titrant streams over time. It consists of creating different but precisely defined concentration gradients of titrant and analyte in each successively formed monosegments, and is based on using the calculated titrant dilution factor. The procedure was verified by complexometric titration of Fe(III) in the form of a complex with sulfosalicylic acid, using EDTA as a titrant. Fe(III) and Fe(II) (after oxidation to Fe(III) with the use of H2O2) were determined with good precision (CV lower than 1.7%, n = 6) and accuracy ( | RE | lower than 3.3%). The approach was applied to determine Fe(III) and Fe(II) in artesian water samples. Results of determinations were consistent with values obtained using the ICP–OES reference method. Using the procedure, it was possible to perform titration in 6 min for a wide range of analyte concentrations, using 2.4 mL of both sample and titrant. Full article
(This article belongs to the Special Issue Modern Flow Analysis)
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14 pages, 2712 KiB  
Article
An Automated SeaFAST ICP-DRC-MS Method for the Determination of 90Sr in Spent Nuclear Fuel Leachates
by Víctor Vicente Vilas, Sylvain Millet, Miguel Sandow, Luis Iglesias Pérez, Daniel Serrano-Purroy, Stefaan Van Winckel and Laura Aldave de las Heras
Molecules 2020, 25(6), 1429; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25061429 - 21 Mar 2020
Cited by 7 | Viewed by 2848
Abstract
To reduce uncertainties in determining the source term and evolving condition of spent nuclear fuel is fundamental to the safety assessment. ß-emitting nuclides pose a challenging task for reliable, quantitative determination because both radiometric and mass spectrometric methodologies require prior chemical purification for [...] Read more.
To reduce uncertainties in determining the source term and evolving condition of spent nuclear fuel is fundamental to the safety assessment. ß-emitting nuclides pose a challenging task for reliable, quantitative determination because both radiometric and mass spectrometric methodologies require prior chemical purification for the removal of interfering activity and isobars, respectively. A method for the determination of 90Sr at trace levels in nuclear spent fuel leachate samples without sophisticated and time-consuming procedures has been established. The analytical approach uses a commercially available automated pre-concentration device (SeaFAST) coupled to an ICP-DRC-MS. The method shows good performances with regard to reproducibility, precision, and LOD reducing the total time of analysis for each sample to 12.5 min. The comparison between the developed method and the classical radiochemical method shows a good agreement when taking into account the associated uncertainties. Full article
(This article belongs to the Special Issue Modern Flow Analysis)
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12 pages, 1056 KiB  
Article
Flow-Based Dynamic Approach to Assess Bioaccessible Zinc in Dry Dog Food Samples
by Bruno J. R. Gregório, Ana Margarida Pereira, Sara R. Fernandes, Elisabete Matos, Francisco Castanheira, Agostinho A. Almeida, António J. M. Fonseca, Ana Rita J. Cabrita and Marcela A. Segundo
Molecules 2020, 25(6), 1333; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25061333 - 15 Mar 2020
Cited by 8 | Viewed by 2594
Abstract
This work proposes a simple and easy-to-use flow-through system for the implementation of dynamic extractions, aiming at the evaluation of bioaccessible zinc and the characterization of leaching kinetics in dry dog food samples. The kinetic profile of Zn extraction was determined by flame [...] Read more.
This work proposes a simple and easy-to-use flow-through system for the implementation of dynamic extractions, aiming at the evaluation of bioaccessible zinc and the characterization of leaching kinetics in dry dog food samples. The kinetic profile of Zn extraction was determined by flame atomic absorption spectroscopy and the results were fitted in an exponential function (R2 > 0.960) compatible with a two first-order reactions model. Values of fast leachable Zn ranged from 83 ± 1 to 313 ± 5 mg of Zn per kg of sample, with associated rate constants ranging from 0.162 ± 0.004 to 0.290 ± 0.014 min−1. Similar results were observed compared to the static batch extraction. The percentage of bioaccessible Zn ranged from 49.0 to 70.0%, with an average value of 58.2% in relation to total Zn content. Principal component analysis regarding the variables fast leachable Zn, associated rate constant, total Zn, and market segment, has shown that 84.6% of variance is explained by two components, where the second component (24.0%) presented loadings only for the fast leachable Zn and associated rate constant. The proposed method is suitable for the fast evaluation (<1 h) of leaching kinetics and bioaccessibility in dry dog food. Full article
(This article belongs to the Special Issue Modern Flow Analysis)
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10 pages, 1295 KiB  
Article
Automated Photochemically Induced Method for the Quantitation of the Neonicotinoid Thiacloprid in Lettuce
by J. Jiménez-López, E.J. Llorent-Martínez, S. Martínez-Soliño and A. Ruiz-Medina
Molecules 2019, 24(22), 4089; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules24224089 - 12 Nov 2019
Cited by 6 | Viewed by 2066
Abstract
In this work, we present an automated luminescence sensor for the quantitation of the insecticide thiacloprid, one of the main neonicotinoids, in lettuce samples. A simple and automated manifold was constructed, using multicommutated solenoid valves to handle all solutions. The analyte was online [...] Read more.
In this work, we present an automated luminescence sensor for the quantitation of the insecticide thiacloprid, one of the main neonicotinoids, in lettuce samples. A simple and automated manifold was constructed, using multicommutated solenoid valves to handle all solutions. The analyte was online irradiated with UV light to produce a highly fluorescent photoproduct (λexc/λem = 305/370 nm/nm) that was then retained on a solid support placed in the flow cell. In this way, the pre-concentration of the photoproduct was achieved in the detection area, increasing the sensitivity of the analytical method. A method-detection limit of 0.24 mg kg−1 was achieved in real samples, fulfilling the Maximum Residue Limit (MRL) of The European Union for thiacloprid in lettuce (1 mg kg−1). A sample throughput of eight samples per hour was obtained. Recovery experiments were carried out at values close to the MRL, obtaining recovery yields close to 100% and relative standard deviations lower than 5%. Hence, this method would be suitable for routine analyses in quality control, as an alternative to other existing methods. Full article
(This article belongs to the Special Issue Modern Flow Analysis)
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12 pages, 967 KiB  
Article
Enzymatic Reactions in a Lab-on-Valve System: Cholesterol Evaluations
by Jucineide S. Barbosa, Marieta L.C. Passos, M. das Graças A. Korn and M. Lúcia M.F.S. Saraiva
Molecules 2019, 24(16), 2890; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules24162890 - 09 Aug 2019
Cited by 6 | Viewed by 3198
Abstract
The micro sequential injection analysis / lab-on-valve (µSIA-LOV) system is a miniaturized SIA system resulting from the implementation of a lab-on-valve (LOV) atop of the selection valve. It integrates the detection cell and the sample processing channels into the same device, promoting the [...] Read more.
The micro sequential injection analysis / lab-on-valve (µSIA-LOV) system is a miniaturized SIA system resulting from the implementation of a lab-on-valve (LOV) atop of the selection valve. It integrates the detection cell and the sample processing channels into the same device, promoting the reduction of reagent consumption and waste generation, the improvement of the versatility, and the reduction of the time of analysis. All of these characteristics are really relevant to the implementation of enzymatic reactions. Additionally, the evaluation of cholesterol in serum samples is widely relevant in clinical diagnosis, since higher values of cholesterol in human blood are actually an important risk factor for cardiovascular problems. An automatic methodology was developed based on the µSIA-LOV system in order to evaluate its advantages in the implementation of enzymatic reactions performed by cholesterol esterase, cholesterol oxidase and peroxidase. Considering these reactions, the developed methodology was also used for the evaluation of cholesterol in human serum samples, showing reliable and accurate results. The developed methodology presented detection and quantification limits of 1.36 and 4.53 mg dL−1 and a linear range up to 40 mg dL−1. This work confirmed that this µSIA-LOV system is a simple, rapid, versatile, and robust analytical tool for the automatic implementation of enzymatic reactions performed by cholesterol esterase, cholesterol oxidase, and peroxidase. It is also a useful alternative methodology for the routine determinations of cholesterol in real samples, even when compared with other automatic methodologies. Full article
(This article belongs to the Special Issue Modern Flow Analysis)
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Review

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27 pages, 2711 KiB  
Review
Dynamic Flow Approaches for Automated Radiochemical Analysis in Environmental, Nuclear and Medical Applications
by Jixin Qiao
Molecules 2020, 25(6), 1462; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25061462 - 24 Mar 2020
Cited by 12 | Viewed by 3676
Abstract
Automated sample processing techniques are desirable in radiochemical analysis for environmental radioactivity monitoring, nuclear emergency preparedness, nuclear waste characterization and management during operation and decommissioning of nuclear facilities, as well as medical isotope production, to achieve fast and cost-effective analysis. Dynamic flow based [...] Read more.
Automated sample processing techniques are desirable in radiochemical analysis for environmental radioactivity monitoring, nuclear emergency preparedness, nuclear waste characterization and management during operation and decommissioning of nuclear facilities, as well as medical isotope production, to achieve fast and cost-effective analysis. Dynamic flow based approaches including flow injection (FI), sequential injection (SI), multi-commuted flow injection (MCFI), multi-syringe flow injection (MSFI), multi-pumping flow system (MPFS), lab-on-valve (LOV) and lab-in-syringe (LIS) techniques have been developed and applied to meet the analytical criteria under different situations. Herein an overall review and discussion on these techniques and methodologies developed for radiochemical separation and measurement of various radionuclides is presented. Different designs of flow systems with combinations of radiochemical separation techniques, such as liquid–liquid extraction (LLE), liquid–liquid microextraction (LLME), solid phase extraction chromatography (SPEC), ion exchange chromatography (IEC), electrochemically modulated separations (EMS), capillary electrophoresis (CE), molecularly imprinted polymer (MIP) separation and online sensing and detection systems, are summarized and reviewed systematically. Full article
(This article belongs to the Special Issue Modern Flow Analysis)
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52 pages, 6486 KiB  
Review
Flow Chemistry in Contemporary Chemical Sciences: A Real Variety of Its Applications
by Marek Trojanowicz
Molecules 2020, 25(6), 1434; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25061434 - 21 Mar 2020
Cited by 44 | Viewed by 8646
Abstract
Flow chemistry is an area of contemporary chemistry exploiting the hydrodynamic conditions of flowing liquids to provide particular environments for chemical reactions. These particular conditions of enhanced and strictly regulated transport of reagents, improved interface contacts, intensification of heat transfer, and safe operation [...] Read more.
Flow chemistry is an area of contemporary chemistry exploiting the hydrodynamic conditions of flowing liquids to provide particular environments for chemical reactions. These particular conditions of enhanced and strictly regulated transport of reagents, improved interface contacts, intensification of heat transfer, and safe operation with hazardous chemicals can be utilized in chemical synthesis, both for mechanization and automation of analytical procedures, and for the investigation of the kinetics of ultrafast reactions. Such methods are developed for more than half a century. In the field of chemical synthesis, they are used mostly in pharmaceutical chemistry for efficient syntheses of small amounts of active substances. In analytical chemistry, flow measuring systems are designed for environmental applications and industrial monitoring, as well as medical and pharmaceutical analysis, providing essential enhancement of the yield of analyses and precision of analytical determinations. The main concept of this review is to show the overlapping of development trends in the design of instrumentation and various ways of the utilization of specificity of chemical operations under flow conditions, especially for synthetic and analytical purposes, with a simultaneous presentation of the still rather limited correspondence between these two main areas of flow chemistry. Full article
(This article belongs to the Special Issue Modern Flow Analysis)
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Other

22 pages, 2876 KiB  
Tutorial
The Automation Technique Lab-In-Syringe: A Practical Guide
by Burkhard Horstkotte and Petr Solich
Molecules 2020, 25(7), 1612; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25071612 - 01 Apr 2020
Cited by 23 | Viewed by 4430
Abstract
About eight years ago, a new automation approach and flow technique called “Lab-In-Syringe” was proposed. It was derived from previous flow techniques, all based on handling reagent and sample solutions in a flow manifold. To date Lab-In-Syringe has evidently gained the interest of [...] Read more.
About eight years ago, a new automation approach and flow technique called “Lab-In-Syringe” was proposed. It was derived from previous flow techniques, all based on handling reagent and sample solutions in a flow manifold. To date Lab-In-Syringe has evidently gained the interest of researchers in many countries, with new modifications, operation modes, and technical improvements still popping up. It has proven to be a versatile tool for the automation of sample preparation, particularly, liquid-phase microextraction approaches. This article aims to assist newcomers to this technique in system planning and setup by overviewing the different options for configurations, limitations, and feasible operations. This includes syringe orientation, in-syringe stirring modes, in-syringe detection, additional inlets, and addable features. The authors give also a chronological overview of technical milestones and a critical explanation on the potentials and shortcomings of this technique, calculations of characteristics, and tips and tricks on method development. Moreover, a comprehensive overview of the different operation modes of Lab-In-Syringe automated sample pretreatment is given focusing on the technical aspects and challenges of the related operations. We further deal with possibilities on how to fabricate required or useful system components, in particular by 3D printing technology, with over 20 different elements exemplarily shown. Finally, a short discussion on shortcomings and required improvements is given. Full article
(This article belongs to the Special Issue Modern Flow Analysis)
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