scholarly journals Fluorescent Probe for Ag+ Detection Using SYBR GREEN I and C-C Mismatch

Biosensors ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 6
Author(s):  
Xiaohong Zhou ◽  
Abdul Ghaffar Memon ◽  
Weiming Sun ◽  
Fang Fang ◽  
Jinsong Guo
Keyword(s):  
Fluorescent Probe ◽  
Limit Of Detection ◽  
False Negative ◽  
Silver Ions ◽  
Bath Temperature ◽  
Repeated Measurements ◽  
Sybr Green ◽  
Sybr Green I ◽  
Relative Standard ◽  
Incubation Duration

Among heavy metals silver ions (Ag+) severely impact water, the environment and have serious side effects on human health. This article proposes a facile and ultrasensitive fluorescent probe for the detection of Ag+ ions using SYBR Green I (SGI) and cytosine-rich (C-rich) silver-specific oligonucleotide (SSO). Maximum fluorescent intensities with the highest sensitivity were obtained using a 0.61 dye/SSO base ratio (DBR). The established sensing principle using the optimized parameters for bath temperature, SSO concentration, DBR, ionic strength, pH, reaction time, incubation duration and temperature effect achieved a sensitive limit of detection of 59.9 nM for silver ions (calculated through 3σ, n = 11) with a linear working range of 100–1000 nM and 0.997 R2. The total time for one assay is below 10 min; The relative standard derivation for ten repeated measurements is 8.6%. No blatant interferences were observed in the selectivity test when fluorescent probe is evaluated by investigating the effects of 11 common interference factors in the aqueous matrix. In extreme cases, three false-negative factors were observed, including calcium hardness, magnesium hardness, and hypochlorite. The recovery ratios were within the range of 79~110% for three types of diluted water.

scholarly journals A highly sensitive octopus-like azobenzene fluorescent probe for determination of abamectin B1 in apples

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhenlong Guo ◽  
YiFei Su ◽  
Kexin Li ◽  
MengYi Tang ◽  
Qiang Li ◽  
...  
Keyword(s):  
Fluorescent Probe ◽  
Limit Of Detection ◽  
Quantitative Detection ◽  
Fluorescence Signal ◽  
Ionization Mass ◽  
Limit Of Quantification ◽  
Visible Absorption ◽  
Esi Ms ◽  
Relative Standard ◽  
Ft Ir

AbstractThe development of detecting residual level of abamectin B1 in apples is of great importance to public health. Herein, we synthesized a octopus-like azobenzene fluorescent probe 1,3,5-tris (5′-[(E)-(p-phenoxyazo) diazenyl)] benzene-1,3-dicarboxylic acid) benzene (TPB) for preliminary detection of abamectin B1 in apples. The TPB molecule has been characterized by ultraviolet–visible absorption spectrometry, 1H-nuclear magnetic resonance, fourier-transform infrared (FT-IR), electrospray ionization mass spectroscopy (ESI-MS) and fluorescent spectra. A proper determination condition was optimized, with limit of detection and limit of quantification of 1.3 µg L−1 and 4.4 μg L−1, respectively. The mechanism of this probe to identify abamectin B1 was illustrated in terms of undergoing aromatic nucleophilic substitution, by comparing fluorescence changes, FT-IR and ESI-MS. Furthermore, a facile quantitative detection of the residual abamectin B1 in apples was achieved. Good reproducibility was present based on relative standard deviation of 2.2%. Six carboxyl recognition sites, three azo groups and unique fluorescence signal towards abamectin B1 of this fluorescent probe demonstrated reasonable sensitivity, specificity and selectivity. The results indicate that the octopus-like azobenzene fluorescent probe can be expected to be reliable for evaluating abamectin B1 in agricultural foods.

scholarly journals 2,7-Dichlorofluorescein Hydrazide as a New Fluorescent Probe for Mercury Quantification: Application to Industrial Effluents and Polluted Water Samples

2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
Sureshkumar Kempahanumakkagari ◽  
Pandurangappa Malingappa ◽  
Gopi Ambikapathi ◽  
Devaraju Kuramkote Shivanna
Keyword(s):  
Fluorescent Probe ◽  
Color Change ◽  
Limit Of Detection ◽  
Industrial Effluents ◽  
Amide Bond ◽  
Polluted Water ◽  
Hydrolytic Cleavage ◽  
Range Limit ◽  
Relative Standard ◽  
Interfering Ions

A new fluorescent probe 2,7-dichlorofluorescein hydrazide for mercury quantification in aqueous medium has been described. It is based on the spirolactam ring opening of colorless and nonfluorescent 2,7-dichlorofluorescein hydrazide induced by Hg2+ions through the hydrolytic cleavage of amide bond to produce green-colored highly fluorescent dichlorofluorescein in alkaline medium. The significant color change of this reagent in the presence of mercury ions can be used as a sensitive naked-eye detector. The working range, limit of detection, and relative standard deviations were found to be 0.2–20 ngmL−1, 0.042 ngmL−1, and 0.69% respectively. The proposed method is free from most of the common interfering ions present in the environmental samples. The developed method has been successfully applied to determine trace level mercury from water, soil, and industrial effluents.

scholarly journals Electrochemical detection of ascorbic acid in artificial sweat using a flexible alginate/CuO-modified electrode

2020 ◽  
Vol 187 (9) ◽  
Author(s):  
Bergoi Ibarlucea ◽  
Arnau Pérez Roig ◽  
Dmitry Belyaev ◽  
Larysa Baraban ◽  
Gianaurelio Cuniberti
Keyword(s):  
Ascorbic Acid ◽  
Cyclic Voltammetry ◽  
Electrochemical Detection ◽  
Limit Of Detection ◽  
Low Cost ◽  
Reference Electrode ◽  
Single Step ◽  
Repeated Measurements ◽  
Relative Standard ◽  
Artificial Sweat

Abstract A flexible sensor is presented for electrochemical detection of ascorbic acid in sweat based on single-step modified gold microelectrodes. The modification consists of electrodeposition of alginate membrane with trapped CuO nanoparticles. The electrodes are fabricated at a thin polyimide support and the soft nature of the membrane can withstand mechanical stress beyond requirements for skin monitoring. After characterization of the membrane via optical and scanning electron microscopy and cyclic voltammetry, the oxidative properties of CuO are exploited toward ascorbic acid for amperometric measurement at micromolar levels in neutral buffer and acidic artificial sweat, at ultralow applied potential (− 5 mV vs. Au pseudo-reference electrode). Alternatively, measurement of the horizontal shift of redox peaks by cyclic voltammetry is also possible. Obtaining a limit of detection of 1.97 μM, sensitivity of 0.103 V log (μM)−1 of peak shift, and linear range of 10–150 μM, the effect of possible interfering species present in sweat is minimized, with no observable cross-reaction, thus maintaining a high degree of selectivity despite the absence of enzymes in the fabrication scheme. With a lateral flow approach for sample delivery, repeated measurements show recovery in few seconds, with relative standard deviation of about 20%, which can serve to detect increased loss or absence of vitamin, and yet be improved in future by optimized device designs. This sensor is envisioned as a promising component of wearable devices for e.g. non-invasive monitoring of micronutrient loss through sweat, comprising features of light weight, low cost, and easy fabrication needed for such application.

scholarly journals Development of New PCR Assay with SYBR Green I for Detection of Mycoplasma, Acholeplasma, and Ureaplasma sp. in Cell Cultures

Diagnostics ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 876
Author(s):  
Jolanta Krzysztoń-Russjan ◽  
Jakub Chudziak ◽  
Małgorzata Bednarek ◽  
Elżbieta Lidia Anuszewska
Keyword(s):  
Cell Cultures ◽  
Limit Of Detection ◽  
Sybr Green ◽  
Sybr Green I ◽  
Chain Reaction ◽  
Pcr Assay ◽  
Time Saving ◽  
Detection And Identification ◽  
Polymerase Chain

Mycoplasma, Acholeplasma, and Ureaplasma sp. are atypical bacteria responsible for in vitro cell culture contaminations that can warp the results. These bacteria also cause human and animal infections and may lead to chronic diseases. In developed polymerase chain reaction (PCR) in this study a quantitative PCR with SYBR Green I fluorochrome was applied to facilitate the Mycoplasma, Acholeplasma, and Ureaplasma sp. DNA detection and identification. Screening Test-1 v.1 (triplex qPCR) allowed for the detection of 11 species. Test-1 v.2 (three single qPCRs) pre-identified three subgroups, allowing for the reduction of using single qPCRs in Test-2 for species identification. The range of both tests was consistent with pharmacopeial requirements for microbial quality control of mammal cells and included detection of M. arginini, M. orale, M. hyorhinis, M. fermentans, M. genitalium, M. hominis, M. pneumoniae, M. salivarium, M. pirum, A. laidlawii, and U. urealyticum. Limit of detection values varied between 125–300 and 50–100 number of copies per milliliter in Test-1 and Test-2, respectively. Test-1 and Test-2 showed fully concordant results, allowed for time-saving detection and/or identification of selected species from Mycoplasma, Acholeplasma, and Ureaplasma in tested cell cultures.

A highly sensitive octopus-like azobenzene fluorescent probe for determination of abamectin B1 in apples

2020 ◽  
Author(s):  
Zhenlong Guo ◽  
YiFei Su ◽  
Kexin Li ◽  
MengYi Tang ◽  
Qiang Li ◽  
...  
Keyword(s):  
Fluorescent Probe ◽  
Limit Of Detection ◽  
Quantitative Detection ◽  
Fluorescence Signal ◽  
Ionization Mass ◽  
Limit Of Quantification ◽  
Visible Absorption ◽  
Esi Ms ◽  
Relative Standard ◽  
Ft Ir

Abstract The development of detecting residual level of abamectin B1 in apples is of great importance to public health. Herein, we synthesized a octopus-like azobenzene fluorescent probe 1,3,5-tris (5'-[(E)-(p-phenoxyazo) diazenyl)] benzene-1,3-dicarboxylic acid) benzene (TPB) for preliminary detection of abamectin B1 in apples. The TPB molecule was characterized by ultraviolet-visible absorption spectrometry, 1H-nuclear magnetic resonance, fourier-transform infrared (FT-IR), electrospray ionization mass spectroscopy (ESI-MS) and fluorescent spectrum. A proper determination condition was optimized, with limit of detection and limit of quantification of 1.3 µg L-1 and 4.4 μg L-1, respectively. The mechanism of this probe to identify abamectin B1 was illustrated in terms of undergoing aromatic nucleophilic substitution, by comparing fluorescence changes, FT-IR and ESI-MS. Furthermore, a facile quantitative detection of the residual abamectin B1 in apples was achieved. Good reproducibility was shown based on relative standard deviation of 2.20%. Six carboxyl recognition sites, three azo groups and unique fluorescence signal towards abamectin B1 of this fluorescent probe decided ideal sensitivity, specificity and selectivity. The results show that the octopus-like azobenzene fluorescent probe may be promising for evaluating abamectin B1 in agricultural foods.

scholarly journals A Simple Pre-concentration Method for the Determination of Nickel(II) in Urine Samples Using UV-Vis Spectrophotometry and Flame Atomic Absorption Spectrometry Techniques

2019 ◽  
Vol 19 (3) ◽  
pp. 638 ◽  
Author(s):  
Ahmed Fadhil Khudhair ◽  
Mouyed Khudhair Hassan ◽  
Hasan F. Alesary ◽  
Ahmed S. Abbas
Keyword(s):  
Limit Of Detection ◽  
Ph Effect ◽  
Absorption Spectrometry ◽  
Bath Temperature ◽  
Urine Samples ◽  
Ionic Surfactant ◽  
Concentration Method ◽  
Flame Atomic Absorption ◽  
Relative Standard ◽  
Triton X

The cloud point technique was effectively utilized for extraction and pre-concentration of nickel(II) in urine samples before measurement by UV-Vis spectrophotometer and AAS techniques. The metal response to a para-aminophenol (PAP) reagent in a non-ionic surfactant Triton X-114 medium was to form the Ni-PAP complex. The adopted concentration for PAP, concentration of Triton X-114, pH effect and water bath temperature, incubation time, salt effect, and interference effects were all optimized. The calibration curve was linear over the range of (0.0625–1.25) mg L–1 with a correlation coefficient r2 of 0.9682 for the UV-Vis spectrophotometer at a λmax of 629 nm. The limit of detection was 0.005 mg/L. The relative standard deviation for six replicates was 1.07%. This method was applied successfully to determine copper (II) concentrations in 44 urine samples of occupational worker samples as determined by UV-Vis spectrophotometry and FAAS techniques.

Highly Sensitive Detection of miRNA-155 Using Molecular Beacon-Functionalized Monolayer MoS2 Nanosheet Probes with Duplex-Specific Nuclease-Mediated Signal Amplification

2021 ◽  
Vol 17 (6) ◽  
pp. 1034-1043
Author(s):  
Ying Liu ◽  
Zhou Ding ◽  
Jingjing Zhang ◽  
Chunyuan Song ◽  
Le Zhang ◽  
...  
Keyword(s):  
Human Serum ◽  
Fluorescent Probe ◽  
Molecular Beacon ◽  
Limit Of Detection ◽  
Fluorescence Signal ◽  
Linear Calibration ◽  
Highly Sensitive ◽  
Relative Standard ◽  
Highly Sensitive Detection ◽  
Fluorescence Amplification

MicroRNA-155 (miRNA-155) as a characteristic myeloma-associated biomarker exhibits significant potential application in the diagnosis of multiple myeloma (MM). In this paper, a novel type of molecular beacon (MB)-functionalized monolayer MoS2 nanosheet probe was proposed as fluorescent probe for high-sensitive assays of miRNA-155that uses a duplexspecificnuclease (DSN) enzyme to amplify the fluorescence signal. The preparation and detection conditions of the fluorescent probes were optimized in some aspects, such as the concentration of MoS2 (0.80 μM) and DSN (0.2 U), and the incubation time of DSN (30 min). The probesexhibited a sensitive fluorescence response to miRNA-155 and the fluorescence signal of the assay was significantly amplified by the cleavage of DSN. The relationship between F/F0 and logC miRNA follows a linear calibration curve, and the limit of detection (LOD) of miRNA-155 in 10% human serum is calculated to be 10.96 fM based on this relationship. The good performance and fluorescence amplification effect of the fluorescent probe were confirmed by studying the recovery of miRNA-155 in 10% human serum, which was ranged from 98.32% to 106.3% with a relative standard deviation of less than 4.14%. Besides, the high expression of miRNA-155 in clinic blood of MM patients was sensitively distinguished from healthy peoples by using the proposed probes. The proposed novel fluorescent probe based on the DSN can be used to detect miRNA-155 in human serum and provide a potential, convenient and reliable tool for diagnosis of MM.

scholarly journals Highly Sensitive Detection for Mercury Ions Using Graphene Oxide (GO) Sensors

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1070
Author(s):  
Lei Liu ◽  
Haixia Shi ◽  
Raoqi Li ◽  
Cheng Liu ◽  
Jia Cheng ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Fluorescent Dyes ◽  
Limit Of Detection ◽  
Sybr Green ◽  
Sybr Green I ◽  
Mercury Ions ◽  
Amino Groups ◽  
Highly Sensitive ◽  
Detection Of Signals ◽  
Highly Sensitive Detection

The mercury ion (Hg2+) is one of the heavy metal ions, and its presence in trace amounts can cause physiological damage to an organism. Traditional methods of Hg2+ detection have been useful but have also had numerous limitations and challenges, and as a result, it is important to design new and sophisticated methods that can aid in the detection of Hg2+. In this paper, two fluorescent dyes, carboxyfluorescein (FAM) and SYBR Green I, were used to label and intercalate DNA probes immobilized on the surface of graphene oxide (GO) for sensors to detect Hg2+. FAM and SYBR Green I dye share close excitation and emission wavelength spectra, which can promote and amplify the detection of signals, and also increase the limit of detection (LOD). The results showed that the limit of detection in this method was 0.53 nM. Moreover, when the sensors with double amino groups on the surface of GO were carried out to detect Hg2+, a limit of detection was improved to 0.43 nM. The sensors were then applied in the real sample. The results show that this method has a promising potential in Hg2+ detection.

scholarly journals Simple and Label-Free Fluorescent Detection of Melamine Based on Melamine–Thymine Recognition

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2968 ◽  
Author(s):  
Hualin Yang ◽  
Jiujun Wang ◽  
Qinghua Wu ◽  
Yun Wang ◽  
Li Li ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Chain Structure ◽  
Sybr Green ◽  
Sybr Green I ◽  
Fluorescent Detection ◽  
Fluorescence Signal ◽  
Label Free ◽  
Protein Levels ◽  
Fluorescent Method ◽  
Milk Adulteration

In the past few years, melamine has been illegally added into dairy products to increase the apparent crude protein levels. If humans or animals drink the milk adulteration of melamine, it can form insoluble melamine–cyanurate crystals in their kidneys which causes kidney damage or even death. In the present work, we constructed a simple and label-free fluorescent method for melamine detection based on melamine-thymine recognition. SYBR Green I was utilized as a reporter for this method as it did not require any modification or expensive equipment. In the absence of melamine, polythymine DNA was digested by Exo I, which caused a decrease in the fluorescence signal. In the presence of melamine, the polythymine DNA was able to fold into a double chain structure, however this was done with the help of T-melamine-T mismatches to prevent degradation. Then, the SYBR Green I combined with the double-stranded DNA to result in an intense fluorescence signal. The limit of detection in this method was 1.58 μM, which satisfied the FDA standards. This method also had a good linear relationship within the range of 10–200 μM. In addition, this new method has a good selectivity to distinguish melamine from the component of milk. As a result, we developed a simple and highly selectivity method for melamine detection.

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