Łukasz Tymecki

University of Warsaw | UW · Faculty of Chemistry

A fully mechanized multicommutated flow analysis (MCFA) system for fluorometric determination of creatinine in serum samples is introduced in this paper. The flow system was constructed with microsolenoid pumps and valves and with a 3D-printed flow cell. Fluorometric assay relied on creatinine reaction with 3,5-dinitrobenzoic acid and hydrogen pero...

Proteinuria is a condition in which an excessive amount of protein is excreted in urine. It is, among others, an indicator of kidney disease or risk of cardiovascular disease. Rapid and reliable diagnosis and monitoring of proteinuria is of great importance for both patients and their physicians. For that reason, a paper-based sensor for proteinuri...

Creatinine is a clinically significant analyte used to diagnose kidney condition. However, the literature still lacks in creatinine sensors fulfilling point-of-care testing requirements. In this paper, we have developed colorimetric paper-based creatinine sensors adhering to point-of-care testing principles. The signal readout is accomplished with...

In this paper we have investigated and optimized a non-enzymatic fluorometric creatinine assay. The method was originally described by Blass in the 90s, but we found that besides the reagents mentioned in the paper, an addition of hydrogen peroxide is required to obtain a fluorescent compound. The excitation and emission maxima of the fluorophore a...

A significant problem still exists with the low power output and durability of the bioelectrochemical fuel cells. We constructed a fuel cell with an enzymatic cascade at the anode for efficient energy conversion. The construction involved fabrication of the flow-through cell by three-dimensional printing. Gold nanoparticles with covalently bound na...

In this research, microfluidic paper distance-based systems for the quantification of redox species are proposed. For the preparation of the sensing zone a Prussian Blue (PB) (convertible to Prussian White (PW)) layer was deposited in the channel manufactured by wax-printing technique. According to the chemical properties of PB/PW system, it is pos...

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 a...

Facing the problem of a growing number of analyses, the need for using simple equipment appears. Smartphone-based optical detection is one of the most widely applied ideas nowadays. A personal device such as a smartphone equipped with a camera is affordable even in the source-limited places. After a simple modification, providing the light source o...

A rapid, single-point method for colorimetric creatinine determination has been developed as an alternative for a well-established Jaffé assay, which lacks analytical specificity. 3,5-dinitrobenzoic acid was employed in an alkaline environment as a chromophore instead of picric acid. Apart from the spectrophotometer, a simple optoelectronic detecto...

This letter comments on a recent article in this Journal (Kvittingen, E. V.; Kvittingen, L.; Melø, T. B.; Sjursnes, B. J.; Verley, R. J. Chem. Educ. 2017, 94, 1486–1491) about the great potential of the paired-emitter detector diode (PEDD) concept in the field of analytical chemistry teaching.

Hemodialysis is a life-saving therapy conducted when kidneys fail to work properly and metabolic toxins are not removed by urine. An organism gets intoxicated which rapidly leads to death. Hemodialysis is an ambulatory treatment performed with the use of special devices, namely artificial kidneys. Despite the fact that hemodialysis is carried out u...

Analytical applications of paper-based microfluidic devices, receive much attention and have been heavily investigated in the last few years. Liquid movement in the body of the paper brings the idea of paper-based flow injection analysis (FIA) developed according to lab-on-paper (LOP) concept. In this approach, paper patterned with hydrophobic bord...

Three – dimensional (3D) electrodes are successfully used to overcome the limitations of the low space – time yield and low normalized space velocity obtained in electrochemical processes with two – dimensional electrodes. In this study, we developed a three – dimensional reticulated vitreous carbon – gold (RVC-Au) sponge as a scaffold for enzymati...

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 a...

Integration of immobilized enzymes with light-emitting diodes (LEDs) leads to the development of optoelectronic enzyme-based biosensors. In this work, urease, used as a model enzyme, immobilized in the form of an open-tubular microbioreactor or biosensing membrane that has been integrated with two red LEDs. It forms complete, fiberless, miniaturize...

Two miniature, fibreless, compact and highly integrated flow-through optoelectronic detectors dedicated for photometric and fluorimetric determination of proteins have been developed. Both detectors operating according to paired-emitter-detector-diode methodology are constructed only of light emitting diodes and therefore their total cost is extrem...

A simple multicommutated flow system based on optoelectronic detector, three valves and peristaltic pump only has been developed for photometric determination of alkaline phosphatase activity in human serum. A miniaturized, compact flow-through detector dedicated to selective photometric detection of product formed in the course of the enzyme assay...

Two compact optoelectronic fluorimetric devices operating according to the paired-emitter-detector-diode concept have been developed. The fluorimetric detector, fabricated of three light emitting diodes only, has been applied for the development of fluorimetric optosensor by further integration with sensing solid phase. In these investigations as a...

A cost-effective, highly compact, and versatile optoelectronic device constructed of two ordinary light emitting diodes compatible with optosensing films has been developed. This fibreless device containing chemoreceptor, semiconductor light source, and detector integrated in a miniaturized flow-through cell of low microliter internal volume works...

Two ordinary green light-emitting diodes used as light emitter and detector coupled with simple voltmeter form a complete, cost-effective prototype of a photometric hemoglobinometer. The device has been optimized for cuvette assays of total hemoglobin (Hb) in diluted blood using three different chemical methods recommended for the needs of clinical...

Integration of two light emitting diodes allows construction of a fluorometric paired emitter detector diode (FPEDD)--a compact optoelectronic device useful as a complete flow-through fluorescence detector.

In this paper a concept of very simple measurement system dedicated for simultaneous photometric and fluorometric detection is presented. Only three ordinary unmodified light emitting diodes (LEDs) can be applied in this analytical device: one of them is used in the conventional way as a source of nearly monochromatic light inducing fluorescence, w...

Only two computer-controlled microsolenoid devices, namely two micropumps or one micropump and one microvalve, are sufficient for the construction of on-line dilution modules useful in several flow analytical systems for the calibration using single standard. Three simple constructions of such modules were tested and compared. The most promising is...

Detection of p-nitrophenol, a product of several enzymatic reactions, is useful and important in many fields of modern bioanalytics. Here, we have developed and applied a complete photometer dedicated for such measurements that is extremely economic and easily customized for specific experimental setups. The instrument consists only of paired emit...

Paired emitter-detector diodes (PEDDs) coupled with potentiometric pH-meter or multimeter have been characterized as complete instruments for common photometric measurements as well as optical flow-through detectors. The analytical characteristics of investigated devices have been illustrated by the use of two paired red LEDs for the determination...

According to the concept of paired-emitter-detector diode (PEDD)-based photometry, a light emitting diode (LED) used as a light source together with a second LED serving as a light detector comprises a novel kind of a photometric device. It has been found that coupling of PEDD with an ordinary multimeter used simultaneously as a power supply of LED...

According to the developed model based on Shockley equation and the Lambert-Beer law, PEDD-based photometric devices generate a potentiometric analytical signal that is directly proportional to the analyte concentration.

A novel biosensor obtained by immobilization of alkaline phosphatase at the surface of pH-electrode has been developed and its potential applications have been announced. Although the applied enzyme is not specific and exhibits biocatalytic activity towards many substrates, the biosensor reveals high and specific sensitivity only for monofluorophos...

A simple flow injection system for potentiometric detection of alkaline phosphatase (ALP) activity has been developed and adapted for determination of selected inhibitors of this enzyme. In this system monofluorophosphate (MFP) has been applied as a specific ALP substrate. The use of this substrate enables application of fluoride ion selective elec...

Various planar technologies are employed for developing solid-state sensors having low cost, small size and high reproducibility; thin- and thick-film technologies are most suitable for such productions. Screen-printing is especially suitable due to its simplicity, low-cost, high reproducibility and efficiency in large-scale production. This techno...

A potentiometric complete bioelectrochemical cell manufactured in an integrated strip format has been applied as dialysate urea nitrogen (DUN) biosensor. Both the urea enzyme electrode and reference electrode have been fabricated only by means of screen-printing. This thick-film DUN-biosensor has been applied as detector in a double-channel flow in...

An extremely cheap, complete bioelectrochemical cell for potentiometric determination of urea has been described. The cell consists of two pH-sensitive metal oxide electrodes: one of them plays a role of an internal electrode of the biosensor, whereas the second one serves as a pseudoreference electrode. Either enzyme or biological material contain...

Miniaturized, planar bioelectrochemical cell dedicated for potentiometric detection of urea manufactured in integrated strip format has been developed. The enzyme electrode and the reference electrode, both based on ruthenium dioxide were fabricated only by means of screen-printing. The application of the thick-film technology results in highly rep...

Low-cost and small-size, all-solid-state potentiometric pH-urease electrodes useful for determination of heavy metals ions have been developed by means of screen-printing. The biosensing thick-film is prepared using biocomposite screen-printable material composed of ruthenium dioxide, urease, graphite and organic polymer. Electric circuit and elect...

A convenient and reliable method for large-scale production of miniaturized, planar, all-solid-state reference electrodes is reported. All elements of the Ag/AgCl/KCl reference half-cell i.e. layer of Ag/AgCl (inner electrode), immobilized electrolyte (junction) and encapsulation are fabricated by means of screen-printing technology. The use of pas...

Miniaturized, planar silver ion-selective electrodes based on thick film of silver sulfide are described. The sensors were fabricated entirely by screen-printing, using low-temperature-curing polymer pastes and polyester substrate in form of flexible foils. Application of the thick-film technology results in highly reproducible and economic fabrica...

Thick-film graphite electrodes produced by screen-printing have been investigated as inexpensive disposable potentiometric sensors for determination of heavy metal ions. The modification of graphite paste with copper sulfides caused an improvement of the analytical characteristics of the sensors. The electrodes based on Cu2S-doped graphite film are...

A simple, low-cost and reproducible method for the mass production of potentiometric ion-selective electrodes for copper ions is presented. These planar, strip sensors were obtained by screen-printing. The application of pastes cured at low temperature allows printing of the sensors on low-cost, plastic substrates. The pastes for printing of ion-se...