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1.
Food Chem ; 452: 139613, 2024 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-38744125

RESUMO

This short communication is devoted to a fully-mechanized flow analysis system for the control of beer fermentation process. The developed system is based on microsolenoid flow controlling devices (valves and pumps) and a flow-through optoelectronic detector. All these components are powered and controlled by a Adruino-compatible microprocessor platform that creates an integrated, compact, and robust analytical tool. Multiplication of sample aspiration ports of the analytical system allows for simultaneous monitoring of several independently performed fermentation processes, as well as a single process at the different places of fermentation tank. To demonstrate its practical utility, the developed system has been applied for online and real-time monitoring of yeast propagation and distribution in beer worts in the course of various fermentation processes. Potentially, this flow analysis system can be easily expanded to the form of multianalyte monitor equipped with optoelectronic sensors and biosensors for the determination of other parameters and analytes.


Assuntos
Cerveja , Fermentação , Cerveja/análise , Cerveja/microbiologia , Saccharomyces cerevisiae/metabolismo , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos
2.
Talanta ; 265: 124817, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37418958

RESUMO

The routine method for LDH (Lactate dehydrogenase) activity determination is to monitor the increase of NADH concentration at 340 nm. There are some inconvenience in taking measurements in the near-UV region, especially in the case of serum samples analysis. In this work, two modifications of the routine LDH activity assay based on the use of reducing properties of NADH have been compared. Both methods involved the reduction of compounds that can be easily determined by well-known methods, ferric ion (with ferrozine) and nitrotetrazolium blue (NBT). A fully-mechanized Multicommutated Flow Analysis-Paired Emitter Detector Diode (MCFA-PEDD) system based on solenoid devices was developed and applied for both methods. The linear ranges obtained for Fe-ferrozine and NBT methods are 6.0-200.0 U L-1 and 10.0-250.0 U L-1 with estimated detection limits at 0.2 U L-1 and 4.5 U L-1, respectively. The low LOQ values enabled 10-fold sample dilutions, which is advantageous for samples with limited available volume. The Fe-ferrozine method is more selective for LDH activity in the presence of glucose, ascorbic acid, albumin, bilirubin, copper and calcium ions than NBT method. To confirm the analytical usefulness of the proposed flow system, the analysis of real human serum samples was carried out. The statistic tests showed satisfactory correlation between the results obtained for both developed methods and those received using the reference method.


Assuntos
NAD , Fotometria , Humanos , Ferrozina , Albuminas , Lactato Desidrogenases , L-Lactato Desidrogenase
3.
Anal Chim Acta ; 1210: 339878, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35595361

RESUMO

A fully-mechanized bioanalytical system for the photometric light-driven lactate determination is presented. The system is based on highly integrated four diode flow-through cell in which two UV-LEDs are used for the photochemical reduction of Fe(III) in the presence of lactate whereas LED-photodiode system allows the photometric detection of Fe(II)-Ferrozine complex to be registered. The developed multicommutation flow analysis system consisting of bifunctional optoelectronic device (photodegradation of Fe(III)-lactate complex and detection), solenoid micropumps and microvalves, is fully controlled and powered by the Arduino-compatible electronics. In consequence, independent and precise control of crucial parameters of the assay, including irradiation time and current supplying UV-LEDs is possible. Under optimized condition the system is useful for the lactate determination in the sub-milimolar range of concentration (6.0-300.0 µmol/L) with satisfactory sensitivity (597.1 AU·L/µmol) and detection limit (3.4 µmol/L), significant reduction of sample and reagents consumption (1.25 µL or 0.5 µL for 40- and 100-fold dilution of human serum samples, respectively) and high sample flow throughput (24 detections per hour). As the system offers the monitoring of detection process, the kinetic discrimination of effects from potential interferents is possible, improving the assay selectivity. The practical utility of the designed system was confirmed by its used for analysis of human serum standards. The recovery values were in the range of 92.1-104.2%. As the limit of quantitation offered by the system is significantly lower than physiological lactate levels, the serum samples have to be diluted what results in further decrease of both sample volume required for analysis and nonselective effects from matrix.


Assuntos
Análise de Injeção de Fluxo , Ácido Láctico , Compostos Férricos , Análise de Injeção de Fluxo/métodos , Humanos , Ácido Láctico/análise , Fotometria
4.
Enzyme Microb Technol ; 153: 109899, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34670184

RESUMO

In this publication an alternative approach to investigations of bacterial growth is proposed. Contrary to the conventional physical methods it is based on enzyme activity detection. The procedure for real-time and on-line monitoring of microbial ureolytic activity (applied as a model experimental biosystem) in the flow analysis format is presented. The developed fully-mechanized bioanalytical flow system is composed of solenoid micropumps and microvalves actuated by Arduino microcontroller. The photometric detection based on Nessler reaction is performed using dedicated flow-through optoelectronic detector made of paired light emitting diodes. The developed bioanalytical system allows discrete assaying of microbial urease in the wide range of activity up to 5.4 U mL-1 with detection limit below 0.44 U mL-1, a high sensitivity in the linear range of response (up to 200 mV U-1 mL and relatively high throughput (9 detection per hour). The proposed differential procedure of measurements (i.e. a difference between peaks register for sample with and without external addition of urea is treated as an analytical signal) allows elimination of interfering effects from substrate and products of biocatalysed reaction as well as other components of medium used for microbial growth. The developed bioanalytical system was successfully applied for the control of growth of urease-positive bacteria strains (Proteus vulgaris, Klebsiella pneumoniae and Paracoccus yeei) including examination of effects from various microbial cultivation conditions like temperature, composition of culture medium and amount of substrate required for induction of bacterial enzymatic activity. The developed bioanalytical flow system can be applied for metabolic activity-based estimation of parameters of lag and log phases of microbial growth as well as for detection of decline phase.


Assuntos
Ureia , Urease , Bactérias , Meios de Cultura , Klebsiella pneumoniae
5.
Molecules ; 26(18)2021 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-34577101

RESUMO

A fully mechanized multicommutated flow analysis (MCFA) system dedicated to determining horseradish peroxidase (HRP) activity was developed. Detection was conducted using a flow-through optoelectronic detector-constructed of paired LEDs operating according to the paired emitter-detector diode (PEDD) principle. The PEDD-MCFA system is dedicated to monitoring the enzyme-catalyzed oxidation of p-phenylenediamine (pPD) by a hydrogen peroxide. Under optimized conditions, the presented bioanalytical system was characterized by a linear response range (33.47-200 U/L) with a detection limit at 10.54 U/L HRP activity and 1.66 mV·L/U sensitivity, relatively high throughput (12 signals recordings per hour), and acceptable precision (RSD below 6%). Additionally, the utility of the developed PEDD-MCFA system for the determination of HRP inhibitors allowing the detection of selected thiols at micromolar levels, is demonstrated. The practical utility of the flow system was illustrated by the analysis of some dietary supplements containing L-cysteine, N-acetylcysteine, and L-glutathione.


Assuntos
Técnicas Eletroquímicas/métodos , Ensaios Enzimáticos/métodos , Análise de Injeção de Fluxo/métodos , Peroxidase do Rábano Silvestre/antagonistas & inibidores , Peroxidase do Rábano Silvestre/metabolismo , Técnicas Analíticas Microfluídicas/métodos , Nefelometria e Turbidimetria/métodos , Calibragem , Peróxido de Hidrogênio/metabolismo , Limite de Detecção , Fenilenodiaminas/metabolismo , Compostos de Sulfidrila/química , Compostos de Sulfidrila/metabolismo
6.
Anal Chim Acta ; 1175: 338753, 2021 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-34330448

RESUMO

Undoubtedly, light-emitting diodes (LEDs) and photodiodes (PDs) are indispensable optoelectronic devices in modern analytical chemistry. LEDs can serve as either light emitters or detectors, thus being an alternative to the most popular detection systems consisted of PD. In this contribution, a comparison between LED-LED and LED-PD detectors, operating in turbidimetric and nephelometric modes, has been carried out for immunoprecipitation detection of transferrin and ferritin. The greatest emphasis was placed on the study of detectors responses under different measurement conditions including current powering an emitter, amplification gain in the case of PD as detector or the construction of detection cells designed for the Multicommutated Flow Analysis (MCFA). The assumption was to obtain the fully-mechanized system with simple but efficient detection system to enable the determination of iron-binding proteins occurring at different concentration ranges in human body. As a result, the optimized arrangements of LED-LED and LED-PD setups were characterized by similar analytical characteristics, enabling the determination of transferrin with the detection limit (LOD) of 0.2 mg/L and RSDs of 2.8-4.8% for LED-LED, and LOD of 0.1 mg/L and RSDs of 0.9-3.6% for LED-PD. In the case of ferritin detection, only the response of the LED-PD detector was statistically distinguishable in the range of 130-198 µg/L of protein with recorded analytical signal change of 20 mV value. The addition of polymer for signal enhancement provided the increase of response range to 107-253 µg/L, enabling the developed system for detection of pathological serum ferritin levels.


Assuntos
Análise de Injeção de Fluxo , Transferrina , Ferritinas , Humanos , Imunoprecipitação , Nefelometria e Turbidimetria
7.
J Pharm Biomed Anal ; 186: 113321, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32413826

RESUMO

In this communication a prototype of paper-based analytical device designed for simultaneous determination of orthophosphate and calcium ions, which levels are significant for hyperphosphatemia diagnostics, is presented. The laboratory-on-paper structure for two analytes detection was wax-printed on the surface of filter paper. These two-analyte disposable paper strips are combined with two paired LED-based fluorescence detectors and simple voltmeter used as recorder of analytical signal, what makes the developed device miniature, extremely low-cost, portable and user-friendly. Thus the developed device allows usage outside of specialized clinical laboratory. Moreover, each paper strip is disposable and its utilization is easy and fast and, additionally, burnt strip tests ensure waste non-infectious. The presented LED&Paper-based analytical device provides low detection limits: 1.4 µmol L-1 and 7.4 µmol L-1 for orthophosphate and calcium ions, respectively. The practical utility of the developed device for calcemia/phosphatemia diagnostics is demonstrated using control serum standards and real human serum.


Assuntos
Cálcio/análise , Hiperfosfatemia/diagnóstico , Fosfatos/análise , Cálcio/sangue , Fluorescência , Humanos , Hiperfosfatemia/sangue , Luz , Limite de Detecção , Papel , Fosfatos/sangue
8.
Talanta ; 214: 120881, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32278433

RESUMO

Two analytical strategies for determination of both biocatalytic activity and concentration of ceruloplasmin conditions have been proposed. For this purpose, two constructions of fully-mechanized Multicommutated Flow Analysis (MCFA) systems were designed. The versatility of solenoid pumps and valves arrangement enabled to construct both manifolds using similar flow units, taking into account the different requirements for each method. In the case of ceruloplasmin catalytic activity assay, the kinetic measurements with the use of p-phenylenediamine and hydrogen peroxide were performed. The optimization process was focused on the selection of substrate and oxidizer concentration, incubation time as well as solving the issue of substrate autoxidation. It led to the development of the flow bioanalytical system characterized by following analytical parameters: LOD - 0.07 U mL- 1, LOQ - 0.38 U mL-1, RSD ≤6% with 8 µL consumption of human serum. In turn, for examination of ceruloplasmin concentration, the light-scattering detector was used in MCFA system adapted for immunoprecipitation measurements. In this case, the use of potentiator (polyethylene glycol) turned out to be necessary to obtain satisfactory analytical signals. Such a method allowed to obtain 35 measurements per hour with LOD and LOQ of 0.9 mg L-1 and 3.2 mg L-1, respectively. The usefulness of both MCFA systems was successfully examined by performing analyses of real human serum samples.

9.
Food Chem ; 294: 231-237, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31126458

RESUMO

A fully mechanized Arduino-controlled multi-pumping flow analysis system and procedure for the determination of ß-galactosidase activity are proposed. The applied bioanalytical method is based on the determination of p-nitrophenol formed in the course of enzyme-catalyzed hydrolysis of p-nitrophenyl-galactopyranosides. The photometric detection is performed using dedicated flow-through optoelectronic detector made of paired light emitting diodes. The developed bioanalytical system was applied for evaluation of optimal enzyme detection conditions (pH, temperature and reaction time), selection of appropriate substrate for the assays, comparison of enzymes of different origins (isoenzymes), detection of ß-galactosidase inhibitor and finally to the determination of enzyme activity in some dietary supplements dedicated for people suffering from lactose intolerance. Depending on measurements conditions the developed bioanalytical system allows determination of ß-galactosidase in the wide range of activity (up to 15 U/mL at detection limit ca 0.01 U/mL) with high sample flowthroughput (up to 30 detections per hour). Additionally, the potential utility of the developed analytical system for amyloglucosidase activity assays has been demonstrated.


Assuntos
Galactose/metabolismo , beta-Galactosidase/metabolismo , Biocatálise , Ensaios Enzimáticos , Galactose/química , Concentração de Íons de Hidrogênio , Isoenzimas/antagonistas & inibidores , Isoenzimas/metabolismo , Nitrofenóis/química , Temperatura , beta-Galactosidase/antagonistas & inibidores
10.
Talanta ; 198: 169-178, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-30876546

RESUMO

Universal, customizable design of 3D printed photometric, and fluorometric flow-through detectors have been presented. The developed designs were fabricated with the use of the most affordable 3D printing technique, namely Fused Filament Fabrication, and require neither hardware nor tools to assemble. Numerous variants of detector geometries have also been presented. The designed parameters varied both in aperture (i.e., the internal diameter of the flow channel in an optical path) and in thickness of an absorbing layer. As expected, the geometry of the channels resulted in changes in the internal volumes. Two concepts of fluorometric detectors have also been described. The utility of all developed flow-through detectors was proven with the use of mechanized calibrations of both photometric and fluorometric experiments. Analytical parameters were characterized with the use of two model dyes: bromothymol blue and fluorescein for photometric and fluorometric experiments, respectively. The repeatability of the 3D printed vessels was found at 3.5-8.0% of the mean relative standard deviation (RSD), depending on the construction of the vessel, which is comparable to rather expensive commercially available flow cells. The compatibility of used 3D printing materials was also examined. For both variants of detection light emitting diodes were applied as light emitters. As the light detectors, both CCD spectrophotometers and light-emitting diodes were used.

11.
Enzyme Microb Technol ; 123: 1-7, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30686345

RESUMO

Two fully mechanized flow analysis systems for urease activity assays have been developed, characterized and compared. Both of them are based on almost the same compact system of solenoid micropumps and microvalves controlled and actuated by highly effective, low-power and economic Arduino microcontroller. For photometric detection of ammonia formed in the course of enzymatic hydrolysis of urea, the Berthelot method and the Nessler reaction have been examined. For both these detection schemes very simple dedicated optoelectronic flow-through detectors made of paired light emitting diodes have been developed. In both systems single enzyme assay lasting a few minutes allows determination of urease in activity range 0.02-5.3 U mL-1 with detection limit 0.02 U mL-1 and in 1.3-5.3 U mL-1 range with 0.75 U mL-1 detection limit for Nessler reaction and Berthelot method based systems, respectively. When compared with mechanized Berthelot method, the bioanalytical system based on Nessler reaction offers higher sensitivity, lower detection/determination limits, better selectivity and lower cost of the assay. It has been demonstrated that the developed bioanalytical flow systems could be useful for urease determination in complex biological matrix like plant extracts and media for microbial cultures as well as for inhibitive determination of heavy metals at sub-ppm levels.


Assuntos
Ensaios Enzimáticos/métodos , Fracionamento por Campo e Fluxo/métodos , Ureia/metabolismo , Urease/metabolismo , Humanos , Limite de Detecção
12.
Biosens Bioelectron ; 127: 31-37, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30590220

RESUMO

The fully-mechanized Multicommutated Flow Analysis (MCFA) system for determination of transferrin in human serum has been developed. The analytical methodology concerns immunoprecipitation measurements with the use of LED-based nephelometric flow-through detectors with polymeric light guides. To improve the mechanization degree of the MCFA system, the Do-It-Yourself electronic module for mobile phone control has been developed. The design and structure of an Android software (build using open source application) controlling the operation of presented flow system has been presented. To bypass the problem of nonlinearity of calibration curve caused by the nature of antigen-antibody interactions, the on-line dilution module has been integrated into the presented manifold. Under optimized conditions, the developed flow analysis system is characterized by relatively low limit of detection and quantitation (2.0 and 4.9 mg L-1, respectively), good precision (RSD < 4%), low reagent and sample consumption per one measurement (16 µL of undiluted reagent and 20 µL of undiluted sample without further on-line dilution, respectively) and relatively high throughput (approximately 35 signal recordings per hour). The developed MCFA system enabled to analyze 16 serum samples with the transferrin concentration from 90 to almost 350 mg dL-1 with statistical agreement to the reference method.


Assuntos
Técnicas Biossensoriais/métodos , Proteínas Sanguíneas/isolamento & purificação , Imunoquímica/métodos , Transferrina/isolamento & purificação , Proteínas Sanguíneas/química , Eletrônica , Humanos , Nefelometria e Turbidimetria , Transferrina/química
13.
Talanta ; 190: 193-198, 2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-30172498

RESUMO

In this contribution a highly cost-effective flow analysis system for determination of alkaline phosphatase (ALP) activity is presented. This fully-mechanized bioanalytical system is based on economic solenoid micropumps and microvalves (powered and actuated by Arduino microcontroller) and extremely cheap dedicated optoelectronic flow-through detectors allowing absorbance and fluorescence measurements. The detection schemes for ALP assaying realized in this system are based on orthophosphate determination. For the detection of these ions formed in the course of enzymatic conversion a molybdate method requiring only common and inexpensive chemicals is utilized. Thus, for the enzymatic assays the simplest not-chromogenic/not-fluorogenic ALP substrates can be applied. Such approach results in the use of low-cost reagents for ALP assays, whereas the mechanization of assay causes low consumption of reagents as well as samples. In the course of reported investigations six ALP substrates were examined and the most promising results have been obtained for the inorganic compound - monofluorophosphate (MFP). The obtained linear ranges of absorbance and fluorescence measurements are 100-600 U L-1 and 30-30/30-100 U L-1, with sensitivities of 0.7 mV L-1 U-1 and 2.3/1.0 mV L-1 U-1, respectively. The calculated limits of detection are 5.1 U L-1 (photometry) and 0.9 U L-1 (fluorometry). The throughputs of the developed system are 13 and 12 samples/h for photometric and fluorometric detections, respectively. To demonstrate the practical utility of the developed bioanalytical system the ALP assays in complex matrix samples have been carried out. The results of ALP activity determination in serum samples are well-correlated with those obtained using reference method recommended for routine clinical analysis.


Assuntos
Fosfatase Alcalina/metabolismo , Ensaios Enzimáticos/métodos , Fluorometria/métodos , Fotometria/métodos , Fosfatos/metabolismo
14.
Anal Sci ; 34(2): 161-167, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29434101

RESUMO

A microfluidic method with front-face fluorometric detection was developed for the determination of total inorganic iodine in drinking water. A polydimethylsiloxane (PDMS) microfluidic device was employed in conjunction with the Sandell-Kolthoff reaction, in which iodide catalyzed the redox reaction between Ce(IV) and As(III). Direct alignment of an optical fiber attached to a spectrofluorometer was used as a convenient detector for remote front-face fluorometric detection. Trace inorganic iodine (IO3- and I-) present naturally in drinking water was measured by on-line conversion of iodate to iodide for determination of total inorganic iodine. On-line conversion efficiency of iodate to iodide using the microfluidic device was investigated. Excellent conversion efficiency of 93 - 103% (%RSD = 1.6 - 11%) was obtained. Inorganic iodine concentrations in drinking water samples were measured, and the results obtained were in good agreement with those obtained by an ICP-MS method. Spiked sample recoveries were in the range of 86%(±5) - 128%(±8) (n = 12). Interference of various anions and cations were investigated with tolerance limit concentrations ranging from 10-6 to 2.5 M depending on the type of ions. The developed method is simple and convenient, and it is a green method for iodine analysis, as it greatly reduces the amount of toxic reagent consumed with reagent volumes in the microfluidic scale.


Assuntos
Água Potável/química , Fluorometria/métodos , Iodo/análise , Dispositivos Lab-On-A-Chip , Dimetilpolisiloxanos/química , Iodatos/química , Iodo/química , Limite de Detecção
15.
Talanta ; 178: 31-36, 2018 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-29136828

RESUMO

The utility of strikingly simple and cheap optoelectronic detectors operating according to a Paired-Emitter-Detector-Diode (PEDD) principle for microfluidic paper-based analytical devices (µPAD) has been experimentally confirmed. The prototypes of these compact detectors have been made of only two customary light emitting diodes without any additional optical parts like lens, filters, fibers etc. Moreover, for their operation economic and portable equipment is required (low-power circuit and ordinary voltmeter). Photometric and fluorometric PEDDs for paper devices are developed. In both cases the possibility of their applicability in transmittance and reflectance modes of measurements are presented. In these investigations as model analytes some coloured and fluorescence substances have been handled, but the utility of several developed systems for real chemical analysis has also been demonstrated. The results of photometric determination of hemoglobin in human blood, as well as fluorometric determination of quinine in tonics and calcium ions in mineral waters using various PEDD-µPAD systems have been shown.

16.
Crit Rev Anal Chem ; 48(3): 186-213, 2018 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-29053338

RESUMO

Disaccharides are determined mainly for dietetic purposes, hence the most analyses are carried out for food and drink samples. Its content can also be used to profile groceries in order to identify the origin and quality of the products. They also can be an indicator of the rate of metabolism as well as for the control of some technological and biotechnological processes. Unfortunately most of technological analysis are performed with nonselective polarimetry methods. Sugars due to specific physicochemical properties of compounds are difficult to determine with classical analytical techniques. The most common disaccharides are composed of several types of monomers connected by a different configuration of the glycosidic bond, therefore, there are subject of the same characteristic reactions. This often enforces the need for pre-separation of sample components. Therefore, nowadays the most popular analytical methodologies for disaccharides determination are based on chromatographic and electrophoretic techniques. An alternative is enzymes application that allow both selective recognition of target analyte and its conversion to easy detected product, allowing detection by relatively simple conventional analytical methods. Another approach is the use of advanced chemometric methodologies for computing of data obtained from some spectroscopic techniques. This article is a review of the recent analytical literature devoted to non-selective and selective methods for disaccharide determination in real samples.


Assuntos
Dissacarídeos/análise , Cromatografia , Eletroforese
17.
Anal Chim Acta ; 995: 43-51, 2017 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-29126480

RESUMO

The Multicommutated Flow Analysis (MCFA) system for the estimation of clinical iron parameters: Serum Iron (SI), Unsaturated Iron Binding Capacity (UIBC) and Total Iron Binding Capacity (TIBC) has been proposed. The developed MCFA system based on simple photometric detection of iron with chromogenic agent (ferrozine) enables a speciation of transferrin (determination of free and Fe-bound protein) in human serum. The construction of manifold was adapted to the requirements of measurements under changing conditions. In the course of studies, a different effect of proteins on SI and UIBC determination has been proven. That was in turn the reason to perform two kinds of calibration methods. For measurements in acidic medium for SI/holotransferrin determination, the calibration curve method was applied, characterized by limit of determination and limit of quantitation on the level of 3.4 µmol L-1 and 9.1 µmol L-1, respectively. The determination method for UIBC parameter (related to apotransferrin level) in physiological medium of pH 7.4 forced the use of standard addition method due to the strong influence of proteins on obtaining analytical signals. These two different methodologies, performed in the presented system, enabled the estimation of all three clinical iron/transferrin parameters in human serum samples. TIBC corresponding to total transferrin level was calculated as a sum of SI and UIBC.


Assuntos
Ferro/sangue , Fotometria , Transferrina/análise , Humanos
18.
J Pharm Biomed Anal ; 145: 504-508, 2017 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-28746909

RESUMO

Compact flow-through optoelectronic detectors fabricated by pairing of light emitting diodes have been applied for development of economic flow analysis systems dedicated for iron ions determination. Three analytical methods with different chromogens selectively recognizing iron ions have been compared. Ferrozine and ferene S based methods offer higher sensitivity and slightly lower detection limits than method with 1,10-phenantroline, but narrower ranges of linear response. Each system allows detection of iron in micromolar range of concentration with comparable sample throughput (20 injections per hour). The developed flow analysis systems have been successfully applied for determination of iron in diet supplements. The utility of developed analytical systems for iron release studies from drug formulations has also been demonstrated.


Assuntos
Ferro/análise , Análise de Injeção de Fluxo , Limite de Detecção , Preparações Farmacêuticas
19.
Talanta ; 160: 233-240, 2016 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-27591609

RESUMO

Enzymes are often used in the modern analytical procedures allowing selective recognition and conversion of target analytes into easily detected products. In flow analysis systems, enzymes are predominantly applied in the immobilized forms as flow-through bioreactors. In this research the multicommutated flow analysis (MCFA) system for evaluation and comparison of analytical parameters of bioreactors has been developed. The MCFA manifold allows simultaneous testing up to four bioreactors, but if necessary their number can be easily increased. The system allows comparison of several parameters of tested bioreactors including activity, repeatability, reproducibility, operational and storage stability. The performance of developed bioreactor tester is presented using urea-urease model system based on plastic open-tubular bioreactor with covalently immobilized enzyme. Product of enzymatic reaction is detected using two different chemical methods and by dedicated optoelectronic ammonium detectors. Moreover, the utility of developed MCFA manifold for evaluation of other enzyme bioreactors is demonstrated.


Assuntos
Fosfatase Alcalina/química , Reatores Biológicos , Enzimas Imobilizadas/química , Glucose Oxidase/química , Urease/química , Compostos de Amônio/química , Catálise , Peróxido de Hidrogênio/química , Nitrofenóis/química , Compostos Organofosforados/química , Ureia/química
20.
J Pharm Biomed Anal ; 128: 28-34, 2016 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-27214506

RESUMO

A general concept for the development of flow analysis system for non-invasive, bloodless monitoring of uremic toxins' removal in the course of clinical hemodialysis treatment is presented. The monitor operates in both (discrete and continuous) modes of measurements. In this study as a model uremic marker creatinine has been chosen. The monitor is based on solenoid operated microdevices (pumps and valves) and an optoelectronic flow-through detector made of paired light emitting diodes allowing photometric determination of this metabolite using Jaffé method. Additionally, a simple two microsolenoid pump-based module allowing the modeling of toxin removal by artificial kidney has been developed. The developed monitor has been validated with real samples of postdialysate fluid produced by artificial kidney in the course of clinical hemodialysis treatment. The results of hemodialysis monitoring are fully comparable with those obtained using reference off-line method.


Assuntos
Líquidos Corporais/química , Creatinina/química , Análise de Injeção de Fluxo/métodos , Humanos , Rim/metabolismo , Rins Artificiais , Diálise Renal/métodos
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