A Highly Selective Luminescent Sensor for Detecting Mercuric Ions in Water

2009 ◽  
Vol 62 (12) ◽  
pp. 1593 ◽  
Author(s):  
Sofian M. Kanan ◽  
Imad A. Abu-Yousef ◽  
Nora Hassouneh ◽  
Ahmed Malkawi ◽  
Naser Abdo ◽  
...  
Keyword(s):  
Linear Response ◽  
Limit Of Detection ◽  
Environmental Water ◽  
Zinc Ions ◽  
Ambient Conditions ◽  
Luminescent Sensor ◽  
Sodium Calcium ◽  
Calcium Magnesium ◽  
Mercuric Ions ◽  
Ph Range

A chemoluminescent sensor utilizing the substrate 2,6-pyridinedicarboxaldehydebis(o-hydroxyphenylimine) (S1) was developed for low-concentration detection of mercuric ions in aqueous solutions. The sensor selectively detects mercury in the presence of sodium, calcium, magnesium, and iron ions. A strong binding was observed between the mercuric ions and the substrate at a pH range of 6.5–7.5, which makes the substrate a distinctive luminescence sensor for detecting mercury at ambient conditions. The sensor shows a linear response towards Hg2+ in the concentration range 5.0 × 10–5 to 2.5 × 10–8 M with a limit of detection of 5.0 × 10–8 M. The sensor can also detect zinc ions at a pH of 10 or higher. The results indicate that this sensor has a promising future for the detection of mercury in real environmental water samples.

Formation of water chemistry in the Modonkul river under the action of mine drainage effluent

2020 ◽  
pp. 56-66
Author(s):  
Z. I. Khazheeva ◽  
S. S. Sanzhanova
Keyword(s):  
Water Chemistry ◽  
Mine Drainage ◽  
High Concentration ◽  
Catchment Basin ◽  
Sulfate Anion ◽  
Concentrated Flow ◽  
Sodium Calcium ◽  
Calcium Cation ◽  
Calcium Magnesium ◽  
The Town

The Dzhida ore field in the Zakamensk district of Buryatia features high concentration of mineralization within a small area. The Dzhida deposit is composed of complex ore. The ore field contains commercial-value primary deposits: Pervomai stockwork of molybdenum, Kholtoson tungsten lode and Inkur stockwork of tungsten. The Modonkul river catchment basin lies inside the Dzhida ore field. A real threat to the town of Zakamensk is created by manmade sand-bulk (old) tailings and slurry dump. By now, the concentrated flow of natural and man-made sand enters the low terrace and floodplain of the Modonkul river in the form of a talus train. This study is focused on the influence of the mine drainage effluent and the Inkur tributary on the water chemistry in the Modonkul river. 80 water samples were taken from the surface layer 0-0.5 m thick at five stations. Physicochemical indices of water were measured at the water sampling points, and the water chemistry was analyzed in a laboratory. In the background conditions, cations and anions in the Modonkul water chemistry range in decreasing order as follows: Са2+ > Mg2+ > Na++К+ и HCO - > SO 2- > Cl-. In the zone of mixture of natural and mine process water, the chemistry changes: from hydrocarbonate to sulfate (anion), from calcium-magnesium to sodium-calcium (cation). Downstream the natural chemistry changes to the hydrocabonate-sulfate composition, with prevailing content of calcium in cations. Iron content of water lowers 3-4 times after influx of mine effluents, while the contents of Mn, Zn, Co and Cd grow and then decrease downstream.

Novel palladium(II) selective membrane electrode based on 4-[(5-mercapto-1,3,4-thiadiazol-2-ylimino)methyl]benzene-1,3-diol

2010 ◽  
Vol 75 (5) ◽  
pp. 563-575 ◽  
Author(s):  
Moslem Mohammadi ◽  
Mehdi Khodadadian ◽  
Mohammad K. Rofouei
Keyword(s):  
Limit Of Detection ◽  
Membrane Electrode ◽  
Aqueous Samples ◽  
Selective Determination ◽  
Poly Vinyl Chloride ◽  
Selective Membrane ◽  
Ph Range ◽  
Palladium Content ◽  
Methyl Benzene

A plasticized poly(vinyl chloride) membrane electrode based on 4-[(5-mercapto-1,3,4-thiadiazol-2-ylimino)methyl]benzene-1,3-diol (L) for highly selective determination of palladium(II) (in PdCl42– form) is developed. The electrode showed a good Nernstian response (29.6 ± 0.4 mV per decade) over a wide concentration range (3.1 × 10–7 to 1.0 × 10–2 mol l–1). The limit of detection was 1.5 × 10–7 mol l–1. The electrode has a response time of about 20 s, and it can be used for at least 2 months without observing any considerable deviation from Nernstian response. The proposed electrode could be used in the pH range of 2.5–5.5. The practical utility of the electrode has been demonstrated by its use for the estimation of palladium content in aqueous samples.

scholarly journals Picomolar-Level Melamine Detection via ATP Regulated CeO2 Nanorods Tunable Peroxidase-Like Nanozyme-Activity-Based Colorimetric Sensor: Logic Gate Implementation and Real Sample Analysis

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 178
Author(s):  
Benazir Chishti ◽  
Zubaida A. Ansari ◽  
Hassan Fouad ◽  
Othman Y. Alothman ◽  
Mohamed Hashem ◽  
...  
Keyword(s):  
Linear Response ◽  
Limit Of Detection ◽  
Logic Gate ◽  
Colorimetric Sensor ◽  
Blue Color ◽  
Neutral Ph ◽  
Colorimetric Response ◽  
Relative Standard ◽  
Functional Logic ◽  
Gate Sensor

The capability of functional logic operations is highly intriguing, but far from being realized owing to limited recognition element (RE) and complex readout signals, which limit their applications. In this contribution, for a visual colorimetric sensor for melamine (MEL) we described the construction of two- and three-input AND logic gate by exploiting the intrinsic peroxidase (POD)-like activity of CeO2 nanorods (NRs) (~23.04% Ce3+ fraction and aspect ratio (RTEM) of 3.85 ± 0.18) as RE at acidic pH (4.5). Further ATP piloted catalytic tuning of POD-like activity in CeO2 NRs employed for a functional logic gate-controlled MEL sensing at neutral pH (7.4). AND logic circuit operated MEL sensing record colorimetric response time of 15 min to produce blue color proportionate to MEL concentration. The fabricated nanozyme (CeO2)-based logic gate sensor probe for MEL at pH 4.5 showed a linear response from 0.004 nM to 1.56 nM with a limit of detection (LOD) of 4 pM; while translation from acidic to neutral pH (at 7.4) sensor exhibited linear response ranging from 0.2 nM to 3.12 nM with a LOD value of 17 pM. Through CeO2 POD-like nanozyme behavior under acidic and neutral pH, the fabricated logic gate sensor showed high affinity for MEL, generating prominent visual output with picomolar sensitivity, good reproducibility, and stability with relative standard deviation (RSD) <1% and 2%, respectively. A feasibility study in real samples (raw milk and milk powder) showed good recoveries with negligible matrix effect, an anti-interference experiment revealed sensor selectivity, highlighting robust sensor practical utility. With the merits of high sensitivity, specificity, low cost, and simplified sample processing, the developed logic-controlled colorimetric MEL sensing platform with appropriate modifications can be recognized as a potent methodology for on-site analysis of various food adulterants and related applications.

scholarly journals Surface-Enhanced Oxidation and Determination of Isothipendyl Hydrochloride at an Electrochemical Sensing Film Constructed by Multiwalled Carbon Nanotubes

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
S. N. Prashanth ◽  
Shankara S. Kalanur ◽  
Nagappa L. Teradal ◽  
J. Seetharamappa
Keyword(s):  
Limit Of Detection ◽  
Biological Fluids ◽  
Differential Pulse ◽  
Electrochemical Sensing ◽  
Good Precision ◽  
Multiwalled Carbon ◽  
Limit Of Quantification ◽  
Surface Enhanced ◽  
Ph Range

The electrochemical behavior of isothipendyl hydrochloride (IPH) was investigated at bare and multiwalled-carbon-nanotube modified glassy carbon electrode (MWCNT-GCE). IPH (55 μM) showed two oxidation peaks in Britton-Robinson (BR) buffer of pH 7.0. The oxidation process of IPH was observed to be irreversible over the pH range of 2.5–9.0. The influence of pH, scan rate, and concentration of the drug on anodic peak was studied. A differential pulse voltammetric method with good precision and accuracy was developed for the determination of IPH in pure and biological fluids. The peak current was found to be linearly dependent on the concentration of IPH in the range of 1.25–55 μM. The values of limit of detection and limit of quantification were noticed to be 0.284 and 0.949 μM, respectively.

scholarly journals Wines produced with 'Cabernet Sauvignon' grapes from the region of Bagé in the state of Rio Grande do Sul, Brazil

2017 ◽  
Vol 52 (5) ◽  
pp. 311-318
Author(s):  
Renata Gimenez Sampaio Zocche ◽  
Suziane Antes Jacobs ◽  
Norton Victor Sampaio ◽  
Velci Queiróz de Souza ◽  
Ivan Ricardo Carvalho ◽  
...  
Keyword(s):  
Reducing Sugars ◽  
Block Design ◽  
Cabernet Sauvignon ◽  
Color Intensity ◽  
Total Polyphenols ◽  
Growing Seasons ◽  
Sodium Calcium ◽  
Randomized Complete Block Design ◽  
Total Anthocyanins ◽  
Calcium Magnesium

Abstract: The objective of this work was to characterize 'Cabernet Sauvignon' wines made from grapes cultivated in the region of Bagé, RS, Brazil, during three crop seasons. A randomized complete block design was carried out with three treatments and three replicates.The evaluations were performed for the 2004, 2007, and 2008 growing seasons. 'Cabernet Sauvignon' wines of the 2004, 2008, and 2009 harvests differed for the following parameters: density, alcoholic content, total acidity, pH, reducing sugars, OD 420, 520, and 620, color intensity, total anthocyanins, total polyphenols, sodium, calcium, magnesium, manganese, copper, iron, rubidium, phosphorus, methanol, propanol, 2-methyl-l-propanol, 2, 3 - methyl-l-butanol, and sum of alcohols. 'Cabernet Sauvignon' has potential to be produced in the Bagé region, and to help it to become a wine growing region in Brazil.

scholarly journals Simultaneous quantification of Vibrio metoecus and Vibrio cholerae with its O1 serogroup and toxigenic subpopulations in environmental reservoirs

2019 ◽  
Author(s):  
Tania Nasreen ◽  
Nora A. S. Hussain ◽  
Mohammad Tarequl Islam ◽  
Fabini D. Orata ◽  
Paul C. Kirchberger ◽  
...  
Keyword(s):  
Opportunistic Infections ◽  
Limit Of Detection ◽  
Spatial Scales ◽  
Genetic Material ◽  
Size Fraction ◽  
Environmental Water ◽  
Close Relative ◽  
Toxin Gene ◽  
Actual Distribution ◽  
Temporal And Spatial

ABSTRACTVibrio metoecus is a recently described and little studied causative agent of opportunistic infections in humans, often coexisting with V. cholerae in aquatic environments. However, the relative abundance of V. metoecus with V. cholerae and their population dynamics in aquatic reservoirs is still unknown. We developed a multiplex qPCR assay with a limit of detection of three copies per reaction to simultaneously quantify total V. metoecus and V. cholerae abundance, as well as the toxigenic and O1 serogroup subpopulations of V. cholerae from environmental samples. Four different genes were targeted as specific markers for individual Vibrio species or subpopulations; viuB, a gene encoding a vibriobactin utilization protein, was used to quantify the total V. cholerae population. The cholera toxin gene ctxA provided an estimation of toxigenic V. cholerae abundance, while the rfbO1 gene specifically detected and quantified V. cholerae belonging to the O1 serogroup, which includes almost all lineages of the species responsible for the majority of past and ongoing cholera pandemics. To measure V. metoecus abundance, the gene mcp, encoding methyl accepting chemotaxis protein, was used. Marker specificity was confirmed by testing several isolates of V. cholerae and V. metoecus alongside negative controls of isolates within and outside of the Vibrio genus. Analysis of environmental water samples collected from four different geographic locations including cholera-endemic (Dhaka, Kuakata and Mathbaria in Bangladesh) and non-endemic (Oyster Pond in Falmouth, Massachusetts, USA) regions showed that V. metoecus was only present in the USA site, recurring seasonally. Within the coastal USA site, the non-toxigenic O1 serogroup represented up to ∼18% of the total V. cholerae population. V. cholerae toxigenic O1 serogroup was absent or present in low abundance in coastal Bangladesh (Kuakata and Mathbaria) but constituted a relatively high proportion of the total V. cholerae population sustained throughout the year in inland Bangladesh (Dhaka). A preference for host/particle attachment was observed, as the majority of cells from both Vibrio species (>90%) were identified in the largest water size fraction sampled, composed of particles or organisms >63 μm and their attached bacteria. This is the first study to apply a culture-independent method to quantify V. cholerae or V. metoecus directly in environmental reservoirs of areas endemic and non-endemic for cholera on significant temporal and spatial scales.SIGNIFICANCECholera is a life-threatening disease that requires immediate intervention; it is of prime importance to have fast, accurate and sensitive means to detect V. cholerae. Consistent environmental monitoring of the abundance of V. cholerae along with its toxigenic and O1 serogroup subpopulations could facilitate the determination of the actual distribution of this organism in aquatic reservoirs and thus help to predict an outbreak before it strikes. The lack of substantial temporal and spatial environmental sampling, along with specific quantitative measures, has made this goal elusive so far. The same is true for V. metoecus, a close relative of V. cholerae which has been associated with several clinical infections and could likely pose an emerging threat, readily exchanging genetic material with its more famous relative.

scholarly journals Butyl Benzyl Phthalate in Urban Sewage by Magnetic-Based Immunoassay: Environmental Levels and Risk Assessment

Biosensors ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 45
Author(s):  
Xia Hong ◽  
Yin Cui ◽  
Ming Li ◽  
Yifan Xia ◽  
Daolin Du ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Drinking Water ◽  
Limit Of Detection ◽  
Environmental Water ◽  
Carcinogenic Risk ◽  
Essential Information ◽  
Detection Range ◽  
Urban Sewage ◽  
Butyl Benzyl Phthalate ◽  
Positive Rate

A magnetic-based immunoassay (MBI) combined with biotin-streptavidin amplification was proposed for butyl benzyl phthalate (BBP) investigation and risk assessment. The values of LOD (limit of detection, IC10) and IC50 were 0.57 ng/mL and 119.61 ng/mL, with a detection range of 0.57–24977.71 ng/mL for MBI. The specificity, accuracy and precision are well demonstrated. A total of 36 environmental water samples of urban sewage from Zhenjiang, China, were collected and assessed for BBP contamination. The results show that BBP-positive levels ranged from 2.47 to 89.21 ng/mL, with a positive rate of 77.8%. The health effects of BBP in the urban sewage were within a controllable range, and the ambient severity for health (ASI) was below 1.49. The highest value of AS for ecology (ASII) was 7.43, which indicates a potential harm to ecology. The entropy value of risk quotient was below 100, the highest being 59.47, which poses a low risk to the environment and ecology, indicating that there is a need to strengthen BBP controls. The non-carcinogenic risk of BBP exposure from drinking water was higher for females than that for males, and the non-carcinogenic risk from drinking-water and bathing pathways was negligible. This study could provide an alternative method for detecting BBP and essential information for controlling BBP contamination.

scholarly journals Extraction-Chromogenic System for Cobalt Based on 5-Methyl-4-(2-thiazolylazo) Resorcinol and Benzalkonium Chloride

2021 ◽  
Vol 68 (1) ◽  
pp. 37-43
Author(s):  
Danail G. Georgiev Hristov ◽  
Petya Vassileva Racheva ◽  
Galya Konstantinova Toncheva ◽  
Kiril Blazhev Gavazov
Keyword(s):  
Benzalkonium Chloride ◽  
Limit Of Detection ◽  
Ion Association ◽  
Molar Absorptivity ◽  
Sensitivity Limit ◽  
Deprotonated Form ◽  
Limit Of Quantification ◽  
Optimum Ph ◽  
Ion Associate ◽  
Ph Range

The interaction between CoII and 5-methyl-4-(2-thiazolylazo)-resorcinol (MTAR) was studied in a water-chloroform system, in the presence or absence of benzalkonium chloride (BZC) as a cationic ion-association reagent. The optimum pH, concentration of the reagents and extraction time for the extraction of Co were found. In the presence of BZC, the extracted ion-associate could be represented by the formula (BZ+)[CoIII(MTAR2–)2], where MTAR is in its deprotonated form. The following extraction-spectrophotometric characteristics were determined: absorption maximum, molar absorptivity, Sandell’s sensitivity, limit of detection, limit of quantification, constant of extraction, distribution ratio and fraction extracted. In the absence of BZC, the extraction is incomplete and occurs in a narrow pH range. The extracted chelate contains one deprotonated and one monoprotonated ligand: [CoIII(MTAR2–)(HMTAR–)].

Synthesis, characterization and formulation of sodium calcium silicate bioceramic for drug delivery applications

2016 ◽  
Vol 23 (4) ◽  
pp. 375-380
Author(s):  
P. Manohar Reddy ◽  
Ravy Lakshmi ◽  
Febin Prabhu Dass ◽  
Swamiappan Sasikumar
Keyword(s):  
Drug Delivery ◽  
Calcium Silicate ◽  
Release Kinetics ◽  
Release Profile ◽  
Apatite Formation ◽  
X Ray Diffraction ◽  
Drug Release Profile ◽  
Sodium Calcium ◽  
Calcium Magnesium ◽  
Model Drug

AbstractSodium calcium silicate (Na2CaSiO4) is a bioactive silicate with Na2O, CaO and SiO2 as its basic components, which is similar to that of the composition of bioactive glasses. In the present study, pure sodium calcium silicate was synthesized by rapid combustion technique, and the synthesized sample was characterized by powder X-ray diffraction to check the phase purity. The scaffolds were prepared by varying the ratio of sodium calcium silicate and polyvinyl alcohol, and the apatite-formation ability of the scaffolds was examined by soaking them in a simulated body fluid. The results revealed the formation of hydroxyapatite on the surface of the scaffold after 5 days, which is found to be rapid when compared with the bioactivity of the calcium silicates and calcium magnesium silicates. The scaffolds were also loaded with ciprofloxacin as a model drug and analyzed for its drug release profile using UV spectrophotometer. The release profile did not vary with the change in bioceramic-to-biopolymer ratio, and 60% of the drug was released in 10 days, which is within the appreciable range for a targeted drug delivery system. Moreover, the experimental and simulated values of the release kinetics were compared by applying the existing mathematical model.

New PGE Modified Electrode Comprising Ni NPs/1,5-Diphenylcarbazide Film Capable for Analyzing Oxytocin

2020 ◽  
Vol 18 (11) ◽  
pp. 793-800
Author(s):  
Mahsa JaFari-Pouyani ◽  
Samineh Kaki ◽  
Arash Babakhanian
Keyword(s):  
Cyclic Voltammetry ◽  
Linear Response ◽  
Square Wave Voltammetry ◽  
Limit Of Detection ◽  
Nano Particles ◽  
Square Wave ◽  
Wave Voltammetry ◽  
Microscopy Techniques ◽  
Bare Surface ◽  
Human Blood Serum Sample

This study focuses on the compatibility of square wave voltammetry technique with new modified graphite pencil electrode to quantify Oxytocin. Ni-Nano particles and 1,5-diphenylcarbazide modifiers were quickly electro-deposited by cyclic voltammetry sweeping technique on the bare surface of a graphite pencil electrode. The electrochemical and morphological assessments were accomplished with cyclic voltammetry, square wave voltammetry and scanning electron microscopy techniques. The proposed electrochemical sensor revealed a good electro catalytic response to Oxytocin concerning the parameters α = 0.42, log Ks =3.44 and Γ = 8.72×10−10 in the optimized pH of 4 and the working potential of about 0.35 V. The new sensor also exhibited a linear response to Oxytocin over the concentration range of 125 to 350 nmolL−1 with the limit of detection of 41.53 nmolL−1. Moreover, the applicability of the proposed sensor was successfully examined and it became usable to determine Oxytocin accurately and precisely in real samples such as human blood serum sample without any serious side interference.

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