Multipoint monitor of beer fermentation.

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.

Turbidimetric flow analysis system for the investigation of microbial growth.

The monitoring of life of microbial populations is of the uttermost importance in environmental and food analysis, agriculture, as well as in medicine. The duration of bacteria adaptation to new environmental conditions, its lifetime and the divisions' pace are the key information in many studies. It was found that the fully-mechanized flow analysis system based on solenoid valves and pumps, paired with a dedicated flow-through optoelectronic detector can be successfully applied for monitoring of bacteria growth.

Photometric flow system for the determination of serum lactate dehydrogenase activity.

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.

Sequential Injection Analysis for Rapid Determination of Mercury in Skincare Products Based on Fluorescence Quenching of Eco-Friendly Synthesized Carbon Dots.

This work reports the analysis of mercury using a spectrofluorometric method combined with a sequential injection analysis (SIA) system. This method is based on the measurement of fluorescence intensity of carbon dots (CDs), which is quenched proportionally after adding mercury ions. Herein, the CDs underwent environmentally friendly synthesis using a microwave-assisted approach that provides intensive and efficient energy and shortens reaction time.

Multicommutation flow analysis system for non-enzymatic lactate determination based on light-driven photometric assay.

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.

Multicommutated Flow Analysis System for Determination of Horseradish Peroxidase and Its Inhibitors.

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.

The comparison between light-scattering detectors based on LED and photodiode for immunoprecipitation assays of transferrin and ferritin.

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.

Electrochemical Properties of Lipid Membranes Self-Assembled from Bicelles.

Supported lipid membranes are widely used platforms which serve as simplified models of cell membranes. Among numerous methods used for preparation of planar lipid films, self-assembly of bicelles appears to be promising strategy. Therefore, in this paper we have examined the mechanism of formation and the electrochemical properties of lipid films deposited onto thioglucose-modified gold electrodes from bicellar mixtures.

Towards mechanized biparametric ceruloplasmin assay.

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.

A remote-controlled immunochemical system for nephelometric detection of human serum transferrin.

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.

Microfluidic Analysis with Front-Face Fluorometric Detection for the Determination of Total Inorganic Iodine in Drinking Water.

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.

Photometric flow analysis system for biomedical investigations of iron/transferrin speciation in human serum.

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.

Optoelectronic iron detectors for pharmaceutical flow analysis.

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.

Bianalyte multicommutated flow analysis system for microproteinuria diagnostics.

In this work a bianalyte multicommutated flow analysis (MCFA) system for determination of microproteinuria is presented. The developed MCFA system is based on two dedicated optoelectronic flow-through detectors which allow estimation of urinary protein creatinine ratio. For total protein determination, turbidimetric Exton's method was used, whereas creatinine was determined by the photometric Jaffe reaction.

An immunoprecipitation assay in the multicommutated flow analysis format.

In this contribution, a multicommutated flow analysis (MCFA) system for immunoprecipitation assays is presented. The developed bioanalytical system constructed from microsolenoid devices coupled with an optoelectronic flow-through nephelometric detector is sufficient to monitor the kinetics of antigen-antibody interactions, the effect of which is turbidity. Because of the uncommon shape of the immunoprecipitation response curve, the developed MCFA system contains a special module for on-line dilution of the analyzed samples and for single-standard calibration.

Multicommutated flow analysis system for determination of total protein in cerebrospinal fluid.

A fully mechanized, computer-controlled, multicommutated flow analysis (MCFA) system dedicated for total protein determination in cerebrospinal fluid samples has been developed. For the protein determination the Exton method has been applied. Dedicated turbidimetric and nephelometric flow-through detectors operating according to paired-emitter detector diode principle have been fabricated by integration of two or three respective light emitting diodes.

Biparametric multicommutated flow analysis system for determination of human serum phosphoesterase activity.

A multicommutated flow analysis (MCFA) system constructed of microsolenoid valves and pumps offering simultaneous determination of activity of acid phosphatase (ACP) and alkaline phosphatase (ALP) in human serum samples has been developed. The MCFA system is based on optoelectronic flow-through detector made of two light emitting diodes and operating according to paired emitter detector diode (PEDD) principle. This photometric PEDD device has been dedicated for detection of p-nitrophenol (NP) generated in the course of enzymatic hydrolysis of p-nitrophenyl phosphate and optimized for the determination of NP in human serum samples.

Nephelometry and turbidimetry with paired emitter detector diodes and their application for determination of total urinary protein.

Two miniature and compact optoelectronic devices fabricated by means of integration of light emitting diodes have been developed for turbidimetric and nephelometric measurements. These devices are operating according to paired-emitter-detector-diode (PEDD) principle. The detectors have been characterized using bovine serum albumin and Exton protein assay as a model analyte and a model analytical method, respectively.

Multicommutated flow analysis system for determination of creatinine in physiological fluids by Jaffe method.

For the needs of photometric determination of creatinine according to Jaffe protocol a dedicated paired emitter detector diode (PEDD) detector has been developed. This PEDD device has been constructed in the compact form of flow-through cell (30 μL total volume and 7 mm optical pathlength) integrated with 505 nm LED-based emitter and 525 nm LED-based detector compatible with multicommutated flow analysis (MCFA) system. This fully mechanized MCFA system configured of microsolenoid valves and pumps is operating under microprocessor control.

Serum alkaline phosphatase assay with paired emitter detector diode.

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 has been constructed using two paired light emitting diodes. The proposed analytical procedure based on kinetic methodology of enzyme activity detection and stopped-flow methodology of two-point measurements eliminates interferences caused by intense color of real samples and impurities present in commercial reagents.

Fluorimetric detector and sensor for flow analysis made of light emitting diodes.

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 model analyte and as a model sensing layer useful for solid phase spectrometry, riboflavin and C18-silica have been chosen, respectively.

A single standard calibration module for flow analysis systems based on solenoid microdevices.

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 the one based on the concept of a microvalve controlling dilution ratio of the standard and a solenoid micropump playing a double role: solution pumping device and mixing segments homogenizer.