scholarly journals Sensing Techniques for Organochlorides through Intermolecular Interaction with Bicyclic Amidines

Biosensors ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 413
Author(s):  
Jong-Won Park ◽  
Lee-Woon Jang ◽  
Erik C. Jensen ◽  
Amanda Stockton ◽  
Jungkyu Kim
Keyword(s):  
Environmental Protection Agency ◽  
Limit Of Detection ◽  
Direct Detection ◽  
Colorimetric Assay ◽  
High Sensitivity ◽  
The United States ◽  
Detection Sensitivity ◽  
Detection Mechanism ◽  
Sensing Platform ◽  
High Volatility

Toxic organochloride molecules are widely used in industry for various purposes. With their high volatility, the direct detection of organochlorides in environmental samples is challenging. Here, a new organochloride detection mechanism using 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) is introduced to simplify a sensing method with higher detection sensitivity. Three types of organochloride compounds-trichloroethylene (TCE), dichloromethane (DCM), and dichlorodiphenyltrichloroethane (DDT)—were targeted to understand DCM conjugation chemistry by using nuclear magnetic resonance (NMR) and liquid chromatography with a mass spectrometer (LC-MS). 13C-NMR spectra and LC-MS data indicated that DBN can be labeled on these organochloride compounds by chlorine–nitrogen interaction. Furthermore, to demonstrate the organochloride sensing capability, the labeling yield and limit of detection were determined by a colorimetric assay as well as micellar electrokinetic chromatography (MEKC). The interaction with DBN was most appreciable for TCE, among other organochlorides. TCE was detected at picomolar levels, which is two orders of magnitude lower than the maximum contaminant level set by the United States Environmental Protection Agency. MEKC, in conjunction with this DBN-labeling method, enables us to develop a field-deployable sensing platform for detecting toxic organochlorides with high sensitivity.

Core-shell Cu@C@ZIF-8 composite: a high-performance electrode material for electrochemical sensing of nitrite with high selectivity and sensitivity

2021 ◽  
Author(s):  
Feng Gao ◽  
Xiaolong Tu ◽  
Yongfang Yu ◽  
Yansha Gao ◽  
Jin Zou ◽  
...  
Keyword(s):  
High Performance ◽  
High Selectivity ◽  
Limit Of Detection ◽  
Metal Organic Framework ◽  
High Sensitivity ◽  
Electrochemical Sensing ◽  
Core Shell ◽  
Zeolitic Imidazolate Framework ◽  
Sensing Platform ◽  
The Difference

Abstract Herein, an efficient electrochemical sensing platform is proposed for selective and sensitive detection of nitrite on the basis of Cu@C@Zeolitic imidazolate framework-8 (Cu@C@ZIF-8) heterostructure. Core-shell Cu@C@ZIF-8 composite was synthesized by pyrolysis of Cu-metal-organic framework@ZIF-8 (Cu-MOF@ZIF-8) in Ar atmosphere on account of the difference of thermal stability between Cu-MOF and ZIF-8. For the sensing system of Cu@C@ZIF-8, ZIF-8 with proper pore size allows nitrite diffuse through the shell, while big molecules cannot, which ensures high selectivity of the sensor. On the other hand, Cu@C as electrocatalyst promotes the oxidation of nitrite, thereby resulting high sensitivity of the sensor. Accordingly, the Cu@C@ZIF-8 based sensor presents excellent performance for nitrite detection, which achieves a wide linear response range of 0.1 µM to 300.0 µM, and a low limit of detection (LOD) of 0.033 µM. In addition, the Cu@C@ZIF-8 sensor possesses excellent stability and reproducibility, and was employed to quantify nitrite in sausage samples with recoveries of 95.45-104.80%.

scholarly journals SARS-CoV-2 Direct Detection Without RNA Isolation With Loop-Mediated Isothermal Amplification (LAMP) and CRISPR-Cas12

2021 ◽  
Vol 8 ◽  
Author(s):  
Alfredo Garcia-Venzor ◽  
Bertha Rueda-Zarazua ◽  
Eduardo Marquez-Garcia ◽  
Vilma Maldonado ◽  
Angelica Moncada-Morales ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Direct Detection ◽  
Direct Method ◽  
Rna Extraction ◽  
Rna Isolation ◽  
High Sensitivity ◽  
High Specificity ◽  
Isothermal Amplification ◽  
Clinical Samples ◽  
Loop Mediated Isothermal Amplification

As to date, more than 49 million confirmed cases of Coronavirus Disease 19 (COVID-19) have been reported worldwide. Current diagnostic protocols use qRT-PCR for viral RNA detection, which is expensive and requires sophisticated equipment, trained personnel and previous RNA extraction. For this reason, we need a faster, direct and more versatile detection method for better epidemiological management of the COVID-19 outbreak. In this work, we propose a direct method without RNA extraction, based on the Loop-mediated isothermal amplification (LAMP) and Clustered Regularly Interspaced Short Palindromic Repeats-CRISPR associated protein (CRISPR-Cas12) technique that allows the fast detection of SARS-CoV-2 from patient samples with high sensitivity and specificity. We obtained a limit of detection of 16 copies/μL with high specificity and at an affordable cost. The diagnostic test readout can be done with a real-time PCR thermocycler or with the naked eye in a blue-light transilluminator. Our method has been evaluated on a small set of clinical samples with promising results.

scholarly journals Impedance Sensing Platform for Detection of the Food Pathogen Listeria monocytogenes

Electronics ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 347 ◽  
Author(s):  
Maria Chiriacò ◽  
Ilaria Parlangeli ◽  
Fausto Sirsi ◽  
Palmiro Poltronieri ◽  
Elisabetta Primiceri
Keyword(s):  
Listeria Monocytogenes ◽  
Foodborne Pathogens ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Foodborne Pathogen ◽  
High Sensitivity ◽  
Primary Objective ◽  
Field Application ◽  
Impedance Sensing ◽  
Sensing Platform

A great improvement in food safety and quality controls worldwide has been achieved through the development of biosensing platforms. Foodborne pathogens continue to cause serious outbreaks, due to the ingestion of contaminated food. The development of new, sensitive, portable, high-throughput, and automated platforms is a primary objective to allow detection of pathogens and their toxins in foods. Listeria monocytogenes is one common foodborne pathogen. Major outbreaks of listeriosis have been caused by a variety of foods, including milk, soft cheeses, meat, fermented sausages, poultry, seafood and vegetable products. Due to its high sensitivity and easy setup, electrochemical impedance spectroscopy (EIS) has been extensively applied for biosensor fabrication and in particular in the field of microbiology as a mean to detect and quantify foodborne bacteria. Here we describe a miniaturized, portable EIS platform consisting of a microfluidic device with EIS sensors for the detection of L. monocytogenes in milk samples, connected to a portable impedance analyzer for on-field application in clinical and food diagnostics, but also for biosecurity purposes. To achieve this goal microelectrodes were functionalized with antibodies specific for L. monocytogenes. The binding and detection of L. monocytogenes was achieved in the range 2.2 × 103 cfu/mL to 1 × 102 with a Limit of Detection (LoD) of 5.5 cfu/mL.

Analysis of Contamination Soil with Cu from Road Side by Using Laser Ablation Technique

2013 ◽  
Vol 845 ◽  
pp. 441-445 ◽  
Author(s):  
Mustafa Arab ◽  
Noriah Bidin
Keyword(s):  
Soil Sample ◽  
Environmental Protection Agency ◽  
Limit Of Detection ◽  
Fluorescence Emission ◽  
The United States ◽  
Laser Source ◽  
Integration Time ◽  
Experimental Conditions ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown

In this project, laser induced breakdown spectroscopy (LIBS) has been utilized to determine the heavy element (Copper) in soil sample. LIBS was used in this work to measure the detection limit of Cu in soil sample, on the basis of spectral features, many parameters to improve the sensitivity of LIBS detection of copper are proposed. Q-switch Nd:YAG laser pulse was carried out at 90 mJ and wavelength of 1064 nm to excite the soil samples in purpose of produce a fluorescence emission (plasma), which were analyzed via spectrum analyzer. The important experimental conditions such as the energy of laser source, integration time, the distance and angle of optical fiber from the sparks were optimized for obtain a best LIBS signal. Calibration curve of the Cu peak found to be 236.81 nm as the best peak to calculate the limit of detection (LOD) and found in this study about 2 ppm. From the results the concentrations of Cu is realized to be lower than the allowance limits of 1500 ppm according to the United States Environmental Protection Agency USEPA.

scholarly journals Detection of Glyphosate in Drinking Water: A Fast and Direct Detection Method without Sample Pretreatment

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2961 ◽  
Author(s):  
Jafar Noori ◽  
Maria Dimaki ◽  
John Mortensen ◽  
Winnie Svendsen
Keyword(s):  
Drinking Water ◽  
Limit Of Detection ◽  
Direct Detection ◽  
Tap Water ◽  
Supporting Electrolyte ◽  
Sample Pretreatment ◽  
The United States ◽  
Electrochemical Sensing ◽  
Potential Range ◽  
Measured Signal

Glyphosate (Gly) is one of the most problematic pesticides that repeatedly appears in drinking water. Continuous on-site detection of Gly in water supplies can provide an early warning in incidents of contamination, before the pesticide reaches the drinking water. Here, we report the first direct detection of Gly in tap water with electrochemical sensing. Gold working electrodes were used to detect the pesticide in spiked tap water without any supporting electrolyte, sample pretreatment or electrode modifications. Amperometric measurements were used to quantify Gly to a limit of detection of 2 μM, which is below the regulation limit of permitted contamination of drinking water in the United States. The quantification of Gly was linearly proportional with the measured signal. The selectivity of this method was evaluated by applying the same technique on a Gly Metabolite, AMPA, and on another pesticide, omethoate, with a chemical structure similar to Gly. The testing revealed no interfering electrochemical activity at the potential range used for Gly detection. The simple detection of Gly presented in this work may lead to direct on-site monitoring of Gly contamination at drinking water sources.

Novel electrochemiluminescent materials for sensor applications

2014 ◽  
Vol 174 ◽  
pp. 357-367 ◽  
Author(s):  
Lynn Dennany ◽  
Zahera Mohsan ◽  
Alexander L. Kanibolotsky ◽  
Peter J. Skabara
Keyword(s):  
Redox Reactions ◽  
Limit Of Detection ◽  
Signal To Noise Ratio ◽  
High Sensitivity ◽  
Radical Cations ◽  
Detection Sensitivity ◽  
Sensor Development ◽  
Sensor Applications ◽  
Sensor Devices ◽  
The Impact

Electrochemiluminescence (ECL) uses redox reactions to generate light at an electrode surface, and is gaining increasing attention for biosensor development due to its high sensitivity and excellent signal-to-noise ratio. ECL studies of monodisperse oligofluorene–truxenes (T4 series) have been reported previously, showing the production of stable radical cations and radical anions, generating blue ECL. The compound in this study differs from the original structures, in that there are 2,1,3-benzothiadazole (BT) units inserted between the first and second fluorene units of the quarterfluorenyl arms. It was therefore anticipated that the incorporation of these highly luminescent and ECL-active compounds into sensor development would lead to significant decreases in detection limits. In this contribution, we report on the impact of incorporating these novel complexes into sensor devices on the ECL efficiency, as well as the ability of these to improve the detection sensitivity and decrease the limit of detection using the reagent-free detection of model analytes. The real world impact of these compounds is elucidated through the comparison with more standard ECL materials such as ruthenium-based compounds. The potential for multiple applications is to be examined within this contribution.

scholarly journals Flexible and Reusable Ag Coated TiO2 Nanotube Arrays for Highly Sensitive SERS Detection of Formaldehyde

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1199 ◽  
Author(s):  
Tong Zhu ◽  
Hang Wang ◽  
Libin Zang ◽  
Sila Jin ◽  
Shuang Guo ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Surface Enhanced Raman Spectroscopy ◽  
Catalytic Performance ◽  
Tio2 Nanotube ◽  
Detection Sensitivity ◽  
Sers Substrate ◽  
Environmental Media ◽  
Sensing Platform ◽  
Surface Enhanced Raman ◽  
Sers Detection

Quantitative analysis of formaldehyde (HCHO, FA), especially at low levels, in various environmental media is of great importance for assessing related environmental and human health risks. A highly efficient and convenient FA detection method based on surface-enhanced Raman spectroscopy (SERS) technology has been developed. This SERS-based method employs a reusable and soft silver-coated TiO2 nanotube array (TNA) material, such as an SERS substrate, which can be used as both a sensing platform and a degradation platform. The Ag-coated TNA exhibits superior detection sensitivity with high reproducibility and stability compared with other SERS substrates. The detection of FA is achieved using the well-known redox reaction of FA with 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole (AHMT) at room temperature. The limit of detection (LOD) for FA is 1.21 × 10−7 M. In addition, the stable catalytic performance of the array allows the degradation and cleaning of the AHMT-FA products adsorbed on the array surface under ultraviolet irradiation, making this material recyclable. This SERS platform displays a real-time monitoring platform that combines the detection and degradation of FA.

scholarly journals Impedance Sensing Platform for Detection of the Food Pathogen Listeria Monocytogenes

2018 ◽  
Author(s):  
Maria Serena Chiriacò ◽  
Ilaria Parlangeli ◽  
Palmiro Poltronieri ◽  
Elisabetta Primiceri
Keyword(s):  
Listeria Monocytogenes ◽  
Foodborne Pathogens ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Foodborne Pathogen ◽  
High Sensitivity ◽  
Primary Objective ◽  
Field Application ◽  
Impedance Sensing ◽  
Sensing Platform

A great improvement in food safety and quality controls worldwide has been achieved through the development of biosensing platforms. Foodborne pathogens continue to cause serious outbreaks due to the ingestion of contaminated food. The development of new, sensitive, portable, high-throughput, and automated platforms is a primary objective to allow detection of pathogens and their toxins in foods. Listeria monocytogenes is one common foodborne pathogen. Major outbreaks of listeriosis have been caused by a variety of foods, including milk, soft cheeses, meat, fermented sausages, poultry, seafood and vegetable products. Due to its high sensitivity and easy setup, electrochemical impedance spectroscopy (EIS) has been extensively applied for biosensor fabrication and in particular in the field of microbiology as a mean to detect and quantify foodborne bacteria. Here we describe a miniaturized, portable EIS platform consisting of a microfluidic device with EIS sensors for the detection of L. monocytogenes in milk samples, connected to a portable impedance analyzer for on-field application in clinical and food diagnostics but also for biosecurity purposes. To achieve this goal microelectrodes were functionalized with antibodies specific for L. monocytogenes. The binding and detection of L. monocytogenes was achieved in the range 2.2 x 103 cfu/ml to 1 x 102 with a Limit of Detection (LoD) of 5.5 cfu/ml.

scholarly journals The Fabrication of Amino Acid Incorporated Nanoflowers with Intrinsic Peroxidase-like Activity and Its Application for Efficiently Determining Glutathione with TMB Radical Cation as Indicator

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1099
Author(s):  
Ning Jiang ◽  
Chuang Zhang ◽  
Meng Li ◽  
Shuai Li ◽  
Zhili Hao ◽  
...  
Keyword(s):  
Amino Acid ◽  
High Selectivity ◽  
Storage Stability ◽  
Mechanical Stability ◽  
Limit Of Detection ◽  
Colorimetric Assay ◽  
Detection System ◽  
High Sensitivity ◽  
Peroxidase Mimics ◽  
Application Potential

The assessment of glutathione (GSH) levels is associated with early diagnostics and pathological analysis for various disorders. Among all kinds of techniques for detecting GSH, the colorimetric assay relying on the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) catalyzed by many nanomaterials with peroxidase-like activity attracts increasing attention owing to its outstanding merits, such as high sensitivity and high selectivity. However, the aggregation between the nanomaterials severely hinders the entrance of TMB into the “active site” of these peroxidase mimics. To address this problem, the D-amino acid incorporated nanoflowers possessing peroxidase-like activity with a diameter of 10–15 μm, TMB and H2O2 were employed to establish the detection system for determining the level of glutathione. The larger diameter size of the hybrid nanoflowers substantially averts the aggregation between them. The results confirm that the hybrid nanoflowers detection system presents a low limit of detection, wide linear range, perfect selectivity, good storage stability and desired operational stability for the detection of GSH relying on the intrinsic peroxidase-like activity and favorable mechanical stability of the hybrid nanoflowers, indicating that the hybrid nanoflowers detection system has tremendous application potential in clinical diagnosis and treatment.

scholarly journals A Highly Fluorescent Pyrene-based Sensor for Selective Detection of Fe3+ Ion in Aqueous Medium: DFT and Molecular Docking Studies

2022 ◽  
Author(s):  
Puthiyavalappil Rasin ◽  
Merlin Mary Mathew ◽  
Vipin Manakkadan ◽  
Vishnunarayanan Namboothiri Vadakkedathu Palakkeezhillam ◽  
Sreekanth Anandaram
Keyword(s):  
Molecular Docking ◽  
Environmental Protection Agency ◽  
Density Functional ◽  
Limit Of Detection ◽  
Fluorescent Sensor ◽  
The United States ◽  
Docking Studies ◽  
Spectroscopic Techniques ◽  
K Value ◽  
Molecular Docking Studies

Abstract In this work, we introduce a highly selective and sensitive fluorescent sensor based on pyrene derivative for Fe(III) ion sensing in DMSO/water media. 2-(pyrene-2-yl)-1-(pyrene-2-ylmethyl)-1H-benzo[d]imidazole (PEBD) receptor was synthesized via simple condensation reaction and confirmed by spectroscopic techniques. The receptor exhibits fluorescence quenching in the presence of Fe(III) ions at 440 nm. ESI-MS and Job’s method were used to confirm the 1:1 molar binding ratio of the receptor PEBD to Fe(III) ions. Using the Benesi-Hildebrand equation the binding constant value was determined as 8.485×103 M-1. Furthermore, the limit of detection (LOD, 3σ/K) value was found to be 1.81µM in DMSO/water (95/5, v/v) media. According to the Environmental Protection Agency (EPA) of the United States, it is lower than the acceptable value of Fe3+ in drinking water (0.3 mg/L). The presence of 14 other metal ions such Co2+, Cr3+, Cu2+, Fe2+, Hg2+, Pb2+, K+, Ni2+, Mg2+, Cd2+, Ca2+, Mn2+, Al3+, and Zn2+ did not interfere with the detection of Fe(III) ions. Computational studies of the receptor PEBD were carried out with density functional theory (DFT) using B3LYP/ 6-311G (d, p), LANL2DZ level of theory. Finally, molecular docking studies have been performed to investigate the Cytochrome P450 1A1(CYP1A1) protein inhibitory action of the receptor PEBD.

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