Application of the PEDD flow detector for analysis of natural dissolved organic substances in coloured water

2013 ◽  
Vol 68 (1) ◽  
pp. 29-35 ◽  
Author(s):  
B. Libecki ◽  
S. Kalinowski
Keyword(s):  
Flow Analysis ◽  
High Sensitivity ◽  
Flow Cell ◽  
Sequential Injection Analysis ◽  
Organic Substances ◽  
Water Parameters ◽  
Light Emitting ◽  
Flowing Stream ◽  
Detector Diode

The automated techniques of measurement of water parameters are developed based on flow analysis (flow injection analysis, sequential injection analysis). PEDD detectors (paired emitter–detector diode), built with the use of two paired light-emitting diodes (LEDs) – emission and detection, can serve that purpose. The aim of the studies was to optimize the system for determination of the dissolved organic substances in coloured water with the use of PEDDs in the flowing-stream measurement system. The investigations were conducted for a number of concentrations of the humic, fulvic and tannic acids, which were measured as the dissolved organic carbon (DOC). Three arrangements of diodes (PEDD) with a selected emission spectrum and absorption characteristics were used. A two-beam flow cell was designed for the measurements. The signal from the detection diode was recorded and converted into absorbance through software written for that purpose. The results obtained showed a high sensitivity in relation to the concentration as well as the selectivity in the type of substances studied. A miniature and cheap photometric flow analysis set was proposed, adapted to work with one or several light wavelengths and steered by a microprocessor unit.

A Compact Microcontrolled Microfluidic System for Photometric Determination of Phosphate in Natural Water Samples

2015 ◽  
Vol 68 (7) ◽  
pp. 1108 ◽  
Author(s):  
Osmundo Dantas Pessoa-Neto ◽  
Tiago Almeida Silva ◽  
Vagner Bezerra dos Santos ◽  
Orlando Fatibello-Filho
Keyword(s):  
Light Emitting Diode ◽  
Flow Analysis ◽  
Photometric Determination ◽  
Microfluidic System ◽  
Experimental Conditions ◽  
Light Emitting ◽  
Experimental Parameters ◽  
Led Photometer

A compact environmentally friendly microcontrolled microfluidic device ideal for in situ phosphate determination was developed based on a microsystem based on low-temperature co-fired ceramics (LTCC) coupled to a light-emitting diode (LED)–photometer with a multicommutation flow analysis (MCFA) approach. The experimental parameters of the MCFA analyzer were optimized by chemometric studies. Under the best experimental conditions, limits of detection and quantification of 0.02 mg P L–1 and 0.07 mg P L–1, respectively, and a sampling frequency of 67 h–1 were estimated. Moreover, a low sample consumption of only 60 μL per determination was the other advantage that fully meets the requirements of sustainable research and green chemistry purposes.

scholarly journals Determination of Histamine in Tomatoes by Capillary Electrophoresis

2000 ◽  
Vol 83 (1) ◽  
pp. 89-94 ◽  
Author(s):  
Elek Bolygo ◽  
Paul A Cooper ◽  
K Michael Jessop ◽  
Frank Moffatt
Keyword(s):  
Capillary Electrophoresis ◽  
Signal To Noise Ratio ◽  
High Sensitivity ◽  
Flow Cell ◽  
Voltage Gradient ◽  
Signal To Noise ◽  
Tomato Fruits ◽  
Endogenous Level ◽  
Selection Of

Abstract An improved capillary electrophoresis assay for histamine in crude extracts was developed and used to determine histamine levels in a selection of tomato fruits and pastes. Performance in terms of reproducibility and sensitivity was optimized by use of a high sensitivity detector flow cell, sodium hydroxide rinses, and a voltage gradient. The method was linear down to 0.2 μg/mL (signal-to-noise ratio = 4:1), which was below the endogenous level in all samples.

Development of a Novel Fluorimeter Based on Superluminescent Light-Emitting Diodes and Acousto-Optic Tunable Filter and its Application in the Determination of Chlorophylls a and b

1997 ◽  
Vol 51 (11) ◽  
pp. 1603-1606 ◽  
Author(s):  
Troy A. Alexander ◽  
Guan-Hong Gao ◽  
Chieu D. Tran
Keyword(s):  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Emission Spectra ◽  
High Sensitivity ◽  
Tunable Filter ◽  
Excitation Spectra ◽  
Excitation Light ◽  
Light Emitting ◽  
Chlorophylls A And B

A novel, compact, inexpensive fluorimeter that has high sensitivity and no moving parts has been developed by using super luminescent (bright-blue) light-emitting diodes (SLEDs) and an acousto-optic tunable filter (AOTF). In this instrument, the recently developed gallium nitride SLEDs were used in a counterpropagating configuration to provide excitation light. These SLEDs provide not only high intensity (several milliwatts) but also wide spectral bandwidth in the blue region (from 370 to 570 nm). The AOTF can be placed before the sample to facilitate the measurements of excitation spectra or after the sample for the emission spectra measurements. This fluorimeter is suitable for the sensitive and general fluorescent analysis of a variety of compounds. It has been used, as an example, for the sensitive and simultaneous determination of chlorophylls a and b. Detection limits of 2.30 × 10−9 and 1.10 × 10−9 M have been achieved for chlorophyll a and chlorophyll b, respectively. Index Headings: Superluminescent light-emitting diode; Acousto-optic tunable filter; Fluorescence; Chlorophyll.

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

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5630
Author(s):  
Justyna Głowacka ◽  
Kamil Strzelak ◽  
Robert Koncki
Keyword(s):  
Horseradish Peroxidase ◽  
Flow Analysis ◽  
Response Range ◽  
Flow Through ◽  
Analysis System ◽  
Optimized Conditions ◽  
Catalyzed Oxidation ◽  
Linear Response Range ◽  
Detector Diode

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.

Development of a high sensitivity photometric procedure for the determination of vanadium in mineral and fresh waters employing a downsized multicommuted flow analysis approach

2014 ◽  
Vol 6 (24) ◽  
pp. 9667-9674 ◽  
Author(s):  
Tuanne R. Dias ◽  
Jarbas J. R. Rohwedder ◽  
Marcos A. S. Brasil ◽  
Boaventura F. Reis
Keyword(s):  
Analytical Procedure ◽  
Flow Analysis ◽  
High Sensitivity ◽  
Photometric Determination ◽  
Mineral Waters ◽  
Analysis Approach ◽  
Fresh Waters

This article focuses on the development of an analytical procedure for the photometric determination of vanadium in fresh and mineral waters, implemented employing a downsized multicommuted flow analysis approach.

Atomic absorption determination of Hg (II), Cd (II), and As (III) in natural and waste water after preliminary group preconcentration

2019 ◽  
Vol 85 (2) ◽  
pp. 12-16
Author(s):  
I. V. Saunina ◽  
E. N. Gribanov ◽  
E. R. Oskotskaya
Keyword(s):  
Waste Water ◽  
Atomic Absorption ◽  
High Sensitivity ◽  
Distribution Coefficients ◽  
Neutral Medium ◽  
Atomic Absorption Determination ◽  
Absorption Determination ◽  
Relative Standard ◽  
Preliminary Group

The sorption of Hg (II), Cd (II), and As (III) by natural aluminosilicate is studied. It is shown that the mineral absorbs those toxicants in a rather wide pH range, quantitative extraction of analytes being achieved in a neutral or close to neutral medium (pH values range within 7.0 - 8.0; 6.3 - 7.5; 7.4 - 8.5 for Hg (II), As (III), and Cd (II), respectively). The effect of the time of phase contact on the degree of extraction of elements is shown. The sorption capacity of the mineral in optimal conditions of the medium acidity (0.06 mmol/g for mercury, 0.31 mmol/g for cadmium, and 0.52 mmol/g for arsenic) is determined. The distribution coefficients attain values of aboutnX 103-nX 104. A new combined method for determination of Hg (II), Cd (II), and As (III) in natural and waste water is developed and tested. The method consists in a preliminary group sorption concentration of the analytes by aluminosilicate, desorption of the analytes from the surface of the mineral and their subsequent atomic absorption determination. The correctness of the method is verified in analysis of spiked samples. The method is easy to use and exhibits high sensitivity, reproducibility and accuracy of analyte determination. The relative standard deviation does not exceed 0.13. Economic availability and possibility of using domestic sorption materials are the important advantages of the proposed procedure which can be used in the practice of laboratories monitoring the quality and safety of environmental objects.

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