scholarly journals Platinum Interdigitated Electrode Arrays for Reagent-Free Detection of Copper

2021 ◽  
Author(s):  
Robert Daly ◽  
Tarun Narayan ◽  
Alan O'Riordan ◽  
Pierre Lovera
Keyword(s):  
Limit Of Detection ◽  
Analytical Techniques ◽  
Cost Effective ◽  
Water Quality Monitoring ◽  
In Situ Monitoring ◽  
Trace Detection ◽  
Sample Collection ◽  
Electrode Arrays ◽  
Mineral Acids ◽  
The Status

<p>Water is a precious resource that is under threat from a number of pressures, including release of toxic compounds that can have damaging effect on ecology and human health. The current methods of water quality monitoring are based on sample collection and analysis at dedicated laboratories. This can provide an incomplete picture of the status of the water body as pollution events can be missed. Recently, electrochemical based methods have attracted a lot of attention for environmental sensing owing to their versatility, sensitivity and compatible integration with cost effective, smart and portable readout systems. In the present work, we report on the fabrication and characterization of platinum interdigitated microband electrodes arrays, and their application for trace detection of copper. Using square wave voltammetry after acidification with mineral acids, a limit of detection of 0.8 μg/L was achieved. Copper detection was also under taken on river water samples and compared with standard analytical techniques. The possibility of controlling the pH at the surface of the sensors – thereby avoiding the necessity to add mineral acids – was investigated. By applying potentials driving the water splitting reaction at one comb on the sensors electrode (the protonator), it was possible to lower the pH in the vicinity of the sensing electrode. Detection of standard copper solutions down to 5 μg/L using this technique is reported. This reagent free method of detection opens the way for autonomous, in situ monitoring of pollutants in water bodies.</p>

scholarly journals Platinum Interdigitated Electrode Arrays for Reagent-Free Detection of Copper

2021 ◽  
Author(s):  
Robert Daly ◽  
Tarun Narayan ◽  
Alan O'Riordan ◽  
Pierre Lovera
Keyword(s):  
Limit Of Detection ◽  
Analytical Techniques ◽  
Cost Effective ◽  
Water Quality Monitoring ◽  
In Situ Monitoring ◽  
Trace Detection ◽  
Sample Collection ◽  
Electrode Arrays ◽  
Mineral Acids ◽  
The Status

<p>Water is a precious resource that is under threat from a number of pressures, including release of toxic compounds that can have damaging effect on ecology and human health. The current methods of water quality monitoring are based on sample collection and analysis at dedicated laboratories. This can provide an incomplete picture of the status of the water body as pollution events can be missed. Recently, electrochemical based methods have attracted a lot of attention for environmental sensing owing to their versatility, sensitivity and compatible integration with cost effective, smart and portable readout systems. In the present work, we report on the fabrication and characterization of platinum interdigitated microband electrodes arrays, and their application for trace detection of copper. Using square wave voltammetry after acidification with mineral acids, a limit of detection of 0.8 μg/L was achieved. Copper detection was also under taken on river water samples and compared with standard analytical techniques. The possibility of controlling the pH at the surface of the sensors – thereby avoiding the necessity to add mineral acids – was investigated. By applying potentials driving the water splitting reaction at one comb on the sensors electrode (the protonator), it was possible to lower the pH in the vicinity of the sensing electrode. Detection of standard copper solutions down to 5 μg/L using this technique is reported. This reagent free method of detection opens the way for autonomous, in situ monitoring of pollutants in water bodies.</p>

scholarly journals Platinum-Based Interdigitated Micro-Electrode Arrays for Reagent-Free Detection of Copper

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3544
Author(s):  
Robert Daly ◽  
Tarun Narayan ◽  
Han Shao ◽  
Alan O’Riordan ◽  
Pierre Lovera
Keyword(s):  
Limit Of Detection ◽  
Analytical Techniques ◽  
Cost Effective ◽  
Water Quality Monitoring ◽  
In Situ Monitoring ◽  
Trace Detection ◽  
Sample Collection ◽  
Electrode Arrays ◽  
Mineral Acids ◽  
Micro Electrode Arrays

Water is a precious resource that is under threat from a number of pressures, including, for example, release of toxic compounds, that can have damaging effect on ecology and human health. The current methods of water quality monitoring are based on sample collection and analysis at dedicated laboratories. Recently, electrochemical-based methods have attracted a lot of attention for environmental sensing owing to their versatility, sensitivity and their ease of integration with cost effective, smart and portable readout systems. In the present work, we report on the fabrication and characterization of platinum-based interdigitated microband electrodes arrays, and their application for trace detection of copper. Using square wave voltammetry after acidification with mineral acids, a limit of detection of 0.8 μg/L was achieved. Copper detection was also undertaken on river water samples and compared with standard analytical techniques. The possibility of controlling the pH at the surface of the sensors—thereby avoiding the necessity to add mineral acids—was investigated. By applying potentials to drive the water splitting reaction at one comb of the sensor’s electrode (the protonator), it was possible to lower the pH in the vicinity of the sensing electrode. Detection of standard copper solutions down to 5 μg/L (ppb) using this technique is reported. This reagent free method of detection opens the way for autonomous, in situ monitoring of pollutants in water bodies.

Development of Multiple Water Quality Measurement Devices

2011 ◽  
Vol 695 ◽  
pp. 606-609
Author(s):  
Pill Jae Kwak ◽  
Seog Ku Kim ◽  
Sang Leen Yun ◽  
Sung Won Kang ◽  
Hyun Dong Lee ◽  
...  
Keyword(s):  
Water Quality ◽  
Optical Sensors ◽  
Quality Measurement ◽  
Cost Effective ◽  
Water Quality Monitoring ◽  
In Situ Monitoring ◽  
Quality Monitoring ◽  
Temperature Conductivity ◽  
High Data ◽  
Water Quality Measurement

The water quality measurement device that we developed measures pH, water temperature, conductivity, dissolved oxygen, turbidity and nitrate. And it measures all parameters simultaneously. The water resistant and screw packing technology also applied for improved mechanical reliability during water quality monitoring. A comparison between the performances of major company products (YSI, Hydrolab etc.) and this device don't provide a stark contrast. This device was verified through the KOREA’s Environmental Examination Methods. This device is offered reliable and cost-effective water quality monitoring solutions. Upgrades will be available and will include the technologies that are self-cleaning optical sensors with integrated wipers remove biofouling and maintain high data accuracy and optimal power management and built-in battery compartment extends in situ monitoring periods.

scholarly journals Evaluation of SARS-CoV-2 rapid antigen diagnostic tests for saliva samples

2021 ◽  
Author(s):  
Marie Hagbom ◽  
Noelia Carmona-Vicente ◽  
Sumit Sharma ◽  
Henrik Olsson ◽  
Mikael Jamtberg ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Nucleocapsid Protein ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Rapid Test ◽  
Cost Effective ◽  
Rapid Response ◽  
Diagnostic Tools ◽  
Sample Collection ◽  
Saliva Test

Background: The COVID-19 pandemic has highlighted the need for rapid, cost effective and easy-to-use diagnostic tools for SARS-CoV-2 rapid antigen detection (RAD) for use in point of care settings or as self-tests, to limit disease transmission. Using saliva samples would further greatly facilitate sample collection, diagnostic feasibility, and mass screening. Objective: We tested two rapid antigen immunochromatographic tests designed for detection of SARS-CoV-2 in saliva: Rapid Response COVID-19 Antigen Rapid Test Cassette for oral fluids (Rapid Response) and DIAGNOS COVID-19 Antigen Saliva Test (DIAGNOS). Evaluation of detection limit was performed with purified SARS-CoV-2 nucleocapsid protein and titrated live SARS-CoV-2 virus and compared to Abbott Panbio COVID-19 Ag Rapid Test (Panbio) designed for nasopharyngeal samples. Sensitivity and specificity were further evaluated on RT-qPCR positive and negative saliva samples from individuals hospitalized with COVID-19 (n=34); and asymptomatic health care personnel (n=20). Results: The limit of detection of the saliva test from DIAGNOS was comparable with the Panbio test and showed higher sensitivity than Rapid Response for both nucleocapsid protein and diluted live viruses. DIAGNOS and Rapid Response further detected seven (47%) and five (33%), respectively, of the 15 RT-qPCR positive saliva samples in individuals hospitalized with COVID-19. Of the 39 RT-qPCR negative samples, all were negative with both tests (specificity 100%; 95% c.i. 0.91-1.00). Only one of the RT-qPCR positive saliva samples (Ct 21.6) contained infectious virus as determined by cell culture and was also positive using the saliva RADs. Conclusion: The results show that the DIAGNOS test exhibit a similar limit of detection as the Panbio RAD and may be an important and easy-to-use saliva RAD complement to detect infectious individuals.

Objectives of a Water Quality Monitoring Programme for the International River Basins in a Developing Country in Southern Africa – Mozambique

1984 ◽  
Vol 16 (5-7) ◽  
pp. 33-39
Author(s):  
S J Hugman
Keyword(s):  
Water Quality ◽  
Water Resources ◽  
Industrial Development ◽  
Water Quality Monitoring ◽  
Quality Data ◽  
Sample Collection ◽  
Water Quality Data ◽  
Maximum Benefit ◽  
Management And Development ◽  
International Obligations

Mozambique lies on the south-east coast of Africa. Its Independence, in 1975, was particularly difficult and severely disrupted the economy. All its major rivers rise in neighbouring countries and several, in particular those from South Africa and Swaziland, are already heavily used before crossing the border. Since 1977 the National Water Directorate has been responsible for management and development of water resources. The Directorate includes a hydrology department which maintains field-teams throughout the country. Virtually no water quality data are available from before 1972, when irregular sample collection began. Since Independence, sampling has continued but the Directorate has redefined the objectives of the programme to obtain maximum benefit from very limited resources. These objectives were chosen for economic, hydrological and political reasons. The long-term objectives are to provide the data required for agricultural and industrial development projects, to manage and maintain the quality of Mozambique's water resources, and to meet international obligations. In practice, the capacity of the hydrological service is insufficient to meet these objectives. The targets for the existing programme were therefore chosen to satisfy the most important objectives and to be feasible with present resources. The routine programme is being completely operated by technicians who have no more than nine years schooling.

Green Synthesis and Spectroscopic Studies of Ag-rGO Nanocomposites for Highly Selective Mercury (II) Sensing

2018 ◽  
Vol 9 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Shubhangi J. Mane-Gavade ◽  
Sandip R. Sabale ◽  
Xiao-Ying Yu ◽  
Gurunath H. Nikam ◽  
Bhaskar V. Tamhankar
Keyword(s):  
Green Synthesis ◽  
Color Change ◽  
Limit Of Detection ◽  
Aqueous Media ◽  
Suitable Condition ◽  
Cost Effective ◽  
Spectroscopic Studies ◽  
Calibration Plot ◽  
First Time

Introduction: Herein we report the green synthesis and characterization of silverreduced graphene oxide nanocomposites (Ag-rGO) using Acacia nilotica gum for the first time. Experimental: We demonstrate the Hg2+ ions sensing ability of the Ag-rGO nanocomposites form aqueous medium. The developed colorimetric sensor method is simple, fast and selective for the detection of Hg2+ ions in aqueous media in presence of other associated ions. A significant color change was noticed with naked eye upon Hg2+ addition. The color change was not observed for cations including Sr2+, Ni2+, Cd2+, Pb2+, Mg2+, Ca2+, Fe2+, Ba2+ and Mn2+indicating that only Hg2+ shows a strong interaction with Ag-rGO nanocomposites. Under the most suitable condition, the calibration plot (A0-A) against concentration of Hg2+ was linear in the range of 0.1-1.0 ppm with a correlation coefficient (R2) value 0.9998. Results & Conclusion The concentration of Hg2+ was quantitatively determined with the Limit of Detection (LOD) of 0.85 ppm. Also, this method shows excellent selectivity towards Hg2+ over nine other cations tested. Moreover, the method offers a new cost effective, rapid and simple approach for the detection of Hg2+ in water samples.

scholarly journals Pitfalls in the Immunochemical Determination of β‑Lactam Antibiotics in Water

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 298
Author(s):  
Alexander Ecke ◽  
Rudolf J. Schneider
Keyword(s):  
Limit Of Detection ◽  
Cost Effective ◽  
Enzyme Linked Immunosorbent Assay ◽  
Degree Of Hydrolysis ◽  
Site Analysis ◽  
Antibody Recognition ◽  
Immunochemical Determination ◽  
Key Factor ◽  
Lactam Ring

Contamination of waters with pharmaceuticals is an alarming problem as it may support the evolution of antimicrobial resistance. Therefore, fast and cost-effective analytical methods for potential on-site analysis are desired in order to control the water quality and assure the safety of its use as a source of drinking water. Antibody-based methods, such as the enzyme-linked immunosorbent assay (ELISA), can be helpful in this regard but can also have certain pitfalls in store, depending on the analyte. As shown here for the class of β-lactam antibiotics, hydrolysis of the β‑lactam ring is a key factor in the immunochemical analysis as it influences antibody recognition. With the antibody used in this study, the limit of detection (LOD) in the immunoassay could be significantly reduced by hydrolysis for the five tested penicillins, with the lowest LOD for carbenicillin (0.2 nmol/L) and the greatest impact on penicillins G and V (reduction by 85%). In addition to enhanced quantification, our strategy also provides access to information about the degree of hydrolysis in water samples as shown for the most abundant penicillin amoxicillin.

scholarly journals Electrochemical Detection of Endosulfan Using an AONP-PANI-SWCNT Modified Glassy Carbon Electrode

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 723
Author(s):  
Kgotla K. Masibi ◽  
Omolola E. Fayemi ◽  
Abolanle S. Adekunle ◽  
Amal M. Al-Mohaimeed ◽  
Asmaa M. Fahim ◽  
...  
Keyword(s):  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Limit Of Detection ◽  
Modified Electrodes ◽  
Antimony Oxide ◽  
Current Response ◽  
Carbon Electrode ◽  
Trace Detection ◽  
Limit Of Quantification ◽  
Walled Carbon Nanotubes

This report narrates the successful application of a fabricated novel sensor for the trace detection of endosulfan (EDS). The sensor was made by modifying a glassy-carbon electrode (GCE) with polyaniline (PANI), chemically synthesized antimony oxide nanoparticles (AONPs), acid-functionalized, single-walled carbon nanotubes (fSWCNTs), and finally, the AONP-PANI-SWCNT nanocomposite. The electrochemical properties of the modified electrodes regarding endosulfan detection were investigated via cyclic voltammetry (CV) and square-wave voltammetry. The current response of the electrodes to EDS followed the trend GCE-AONP-PANI-SWCNT (−510 µA) > GCE-PANI (−59 µA) > GCE-AONPs (−11.4 µA) > GCE (−5.52 µA) > GCE-fSWCNTs (−0.168 µA). The obtained results indicated that the current response obtained at the AONP-PANI-SWCNT/GCE was higher with relatively low overpotential compared to those from the other electrodes investigated. This demonstrated the superiority of the AONP-PANI-SWCNT-modified GCE. The AONP-PANI-SWCNT/GCE demonstrated good electrocatalytic activities for the electrochemical reduction of EDS. The results obtained in this study are comparable with those in other reports. The sensitivity, limit of detection (LoD), and limit of quantification (LoQ) of AONP-PANI-SWCNT/GCE towards EDS was estimated to be 0.0623 µA/µM, 6.8 µM, and 20.6 µM, respectively. Selectivity, as well as the practical application of the fabricated sensor, were explored, and the results indicated that the EDS-reduction current was reduced by only 2.0% when interfering species were present, whilst average recoveries of EDS in real samples were above 97%.

scholarly journals Direct diagnostic testing of SARS-CoV-2 without the need for prior RNA extraction

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shan Wei ◽  
Esther Kohl ◽  
Alexandre Djandji ◽  
Stephanie Morgan ◽  
Susan Whittier ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
Diagnostic Testing ◽  
Rna Extraction ◽  
Cost Effective ◽  
Clinical Samples ◽  
Nasopharyngeal Swab ◽  
Percentage Agreement ◽  
Testing Method ◽  
Viral Transport

AbstractThe COVID-19 pandemic has resulted in an urgent need for a rapid, point of care diagnostic testing that could be rapidly scaled on a worldwide level. We developed and tested a highly sensitive and robust assay based on reverse transcription loop mediated isothermal amplification (RT-LAMP) that uses readily available reagents and a simple heat block using contrived spike-in and actual clinical samples. RT-LAMP testing on RNA-spiked samples showed a limit of detection (LoD) of 2.5 copies/μl of viral transport media. RT-LAMP testing directly on clinical nasopharyngeal swab samples in viral transport media had an 85% positive percentage agreement (PPA) (17/20), and 100% negative percentage agreement (NPV) and delivered results in 30 min. Our optimized RT-LAMP based testing method is a scalable system that is sufficiently sensitive and robust to test for SARS-CoV-2 directly on clinical nasopharyngeal swab samples in viral transport media in 30 min at the point of care without the need for specialized or proprietary equipment or reagents. This cost-effective and efficient one-step testing method can be readily available for COVID-19 testing world-wide, especially in resource poor settings.

scholarly journals Determination of amino acids in human biological fluids by high-performance liquid chromatography: critical review

Amino Acids ◽  
2021 ◽  
Author(s):  
Grażyna Gałęzowska ◽  
Joanna Ratajczyk ◽  
Lidia Wolska
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
High Performance ◽  
Hplc Analysis ◽  
Limit Of Detection ◽  
Biological Fluids ◽  
Analytical Techniques ◽  
Epidemiological Studies ◽  
Preparation Conditions

AbstractThe quantitation and qualification of amino acids are most commonly used in clinical and epidemiological studies, and provide an excellent way of monitoring compounds in human fluids which have not been monitored previously, to prevent some diseases. Because of this, it is not surprising that scientific interest in evaluating these compounds has resurfaced in recent years and has precipitated the development of a multitude of new analytical techniques. This review considers recent developments in HPLC analytics on the basis of publications from the last few years. It helps to update and systematize knowledge in this area. Particular attention is paid to the progress of analytical methods, pointing out the advantages and drawbacks of the various techniques used for the preparation, separation and determination of amino acids. Depending on the type of sample, the preparation conditions for HPLC analysis change. For this reason, the review has focused on three types of samples, namely urine, blood and cerebrospinal fluid. Despite time-consuming sample preparation before HPLC analysis, an additional derivatization technique should be used, depending on the detection technique used. There are proposals for columns that are specially modified for amino acid separation without derivatization, but the limit of detection of the substance is less beneficial. In view of the fact that amino acid analyses have been performed for years and new solutions may generate increased costs, it may turn out that older proposals are much more advantageous.

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