scholarly journals A Chelation-Enhanced Fluorescence Assay Using Thiourea Capped Carbonaceous Fluorescent Nanoparticles For As (III) Detection In Water Samples

2021 ◽  
Author(s):  
Susan Mohammadi ◽  
Somayeh Mohammadi ◽  
Abdollah Salimi ◽  
Rezgar Ahmadi
Keyword(s):  
Water Samples ◽  
Limit Of Detection ◽  
Threshold Value ◽  
Water Soluble ◽  
World Health ◽  
Fluorescent Nanoparticles ◽  
Detection Range ◽  
Turn On ◽  
Efficient Detection ◽  
Health Organization

Abstract Herein, we designed a sensitive and selective “Turn-On” fluorescence nanosensor using water-soluble carbonaceous fluorescent nanomaterials (CFNs) functionalized with thiourea (CFNs-thiourea) for efficient detection of trace amounts of arsenic (III) in aqueous samples. The CFNs and CFNs-Thiourea were characterized by transmission electron microscopy (TEM), UV–Visible spectroscopy (UV-vis) and Fourier transformed infrared spectroscopy (FTIR). The emission peak intensity of proposed nanosensor at 425 nm was gradually enhanced on arsenite addition in wide detection range (3.3–828.5 µg L-1) attributed to the binding of arsenite species with sulfur groups of CFNs-thiourea. The limit of detection (LOD) was 0.48 µg L-1 being much lower than the World Health Organization (WHO) recommended threshold value of 10 µg L-1. Furthermore, the as prepared thiourea -CFNs exhibited an superb selectivity for As (III) compared various cations and anions such as; NO3−, NO2−, F−, Ni2+, Fe3+, Cu2+, Ca2+, Mg2+, Zn2+, Fe2+, Hg2+, Pb2+, F-, Cl-, Mn2+, Cr3+, Co2+, Cd2+, Bi3+, Al3+ and As (V) at 100 folds concentration of As (III). The turn on fluorescence nanosensor was successfully exploited for quantification of arsenic in spiked water samples with acceptable efficiencies.

scholarly journals N-Doped Carbon Dots Derived from Melamine and Triethanolamine for Selective Sensing of Fe3+ Ions

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Sathishkumar Munusamy ◽  
Sathish Sawminathan ◽  
Thanigaivelan Arumugham ◽  
Maura Casales Díaz ◽  
Srinivas Godavarthi ◽  
...  
Keyword(s):  
Water Samples ◽  
Carbon Dots ◽  
Limit Of Detection ◽  
Blue Emission ◽  
World Health ◽  
Selective Determination ◽  
N Doping ◽  
Health Organization ◽  
Doped Carbon Dots ◽  
Nitrogen Doped Carbon

This work reports nitrogen-doped carbon dots (NCDs) as a selective sensing probe to detect Fe3+ in water samples. NCD probes were synthesized via solvothermal method using nitrogen-rich melamine and triethanolamine as precursors. Properties of the resulting NCDs were studied using different characterization techniques, through which N-doping was confirmed. The quantum yield of obtained NCDs was measured to be 21%. When excited at 370 nm, the excellent blue emission property makes this probe adoptable for selectively sensing Fe3+ in practical water samples. The limit of detection (LOD) was identified as 216 nM with a good linear range between the concentrations of 0.2-2 μM. The obtained LOD is far less than the World Health Organization (WHO) permissible limits of Fe3+ in water. Interference studies reveal that the presence of other competing ions did not alter the sensing of Fe3+, even at the presence of 10 equivalents which indicates the high selectivity of NCDs towards Fe3+. The reversibility studies showed that adding a cheap and readily available EDTA ligand to the NCD results in fluorescence regeneration, leading to exceptional reusability for the detection of Fe3+. So, the synthesized NCDs can be used as a suitable probe for the selective determination of Fe3+ in real water samples.

scholarly journals Selective and Sensitive Detection of Cyanide Based on the Displacement Strategy Using a Water-Soluble Fluorescent Probe

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Ming La ◽  
Yuanqiang Hao ◽  
Zhaoyang Wang ◽  
Guo-Cheng Han ◽  
Lingbo Qu
Keyword(s):  
Aqueous Solution ◽  
Fluorescent Probe ◽  
Limit Of Detection ◽  
Aqueous Media ◽  
Water Soluble ◽  
World Health ◽  
Selective Detection ◽  
Highly Sensitive ◽  
Health Organization

A water-soluble fluorescent probe (C-GGH) was used for the highly sensitive and selective detection of cyanide (CN−) in aqueous media based on the displacement strategy. Due to the presence of the recognition unit GGH (Gly-Gly-His), the probeC-GGH can coordinate with Cu2+and consequently display ON-OFF type fluorescence response. Furthermore, thein situformed nonfluorescentC-GGH-Cu2+complex can act as an effective OFF-ON type fluorescent probe for sensing CN−anion. Due to the strong binding affinity of CN−to Cu2+, CN−can extract Cu2+fromC-GGH-Cu2+complex, leading to the release ofC-GGH and the recovery of fluorescent emission of the system. The probeC-GGH-Cu2+allowed detection of CN−in aqueous solution with a LOD (limit of detection) of 0.017 μmol/L which is much lower than the maximum contaminant level (1.9 μmol/L) for CN−in drinking water set by the WHO (World Health Organization). The probe also displayed excellent specificity for CN−towards other anions, including F−, Cl−, Br−, I−, SCN−,PO43-,N3-,NO3-, AcO−,SO42-, andCO32-.

scholarly journals A Novel Thiophene-Based Fluorescent Chemosensor for the Detection of Zn2+ and CN−: Imaging Applications in Live Cells and Zebrafish

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5458 ◽  
Author(s):  
Min Seon Kim ◽  
Dongju Yun ◽  
Ju Byeong Chae ◽  
Haeri So ◽  
Hyojin Lee ◽  
...  
Keyword(s):  
Hela Cells ◽  
Fluorescence Enhancement ◽  
Limit Of Detection ◽  
Zinc Ion ◽  
World Health ◽  
Live Cells ◽  
Real Samples ◽  
Turn On ◽  
Health Organization ◽  
Nmr Titrations

A novel fluorescent turn-on chemosensor DHADC ((E)-3-((4-(diethylamino)-2-hydroxybenzylidene)amino)-2,3-dihydrothiophene-2-carboxamide) has been developed and used to detect Zn2+ and CN−. Compound DHADC displayed a notable fluorescence increase with Zn2+. The limit of detection (2.55 ± 0.05 μM) for zinc ion was far below the standard (76 μM) of the WHO (World Health Organization). In particular, compound DHADC could be applied to determine Zn2+ in real samples, and to image Zn2+ in both HeLa cells and zebrafish. Additionally, DHADC could detect CN− through a fluorescence enhancement with little inhibition with the existence of other types of anions. The detection processes of compound DHADC for Zn2+ and CN− were demonstrated with various analytical methods like Job plots, 1H NMR titrations, and ESI-Mass analyses.

scholarly journals A SARS-CoV-2 coronavirus nucleocapsid protein antigen-detecting lateral flow assay

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0258819
Author(s):  
Benjamin D. Grant ◽  
Caitlin E. Anderson ◽  
Luis F. Alonzo ◽  
Spencer H. Garing ◽  
John R. Williford ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
Lateral Flow ◽  
World Health ◽  
Analytical Sensitivity ◽  
Rapid Diagnostics ◽  
Middle Income ◽  
Efficient Detection ◽  
Gamma Irradiated ◽  
Health Organization

Inexpensive, simple, rapid diagnostics are necessary for efficient detection, treatment, and mitigation of COVID-19. Assays for SARS-CoV2 using reverse transcription polymerase chain reaction (RT-PCR) offer good sensitivity and excellent specificity, but are expensive, slowed by transport to centralized testing laboratories, and often unavailable. Antigen-based assays are inexpensive and can be rapidly mass-produced and deployed at point-of-care, with lateral flow assays (LFAs) being the most common format. While various manufacturers have produced commercially available SARS-Cov2 antigen LFAs, access to validated tests remains difficult or cost prohibitive in low-and middle-income countries. Herein, we present a visually read open-access LFA (OA-LFA) using commercially-available antibodies and materials for the detection of SARS-CoV-2. The LFA yielded a Limit of Detection (LOD) of 4 TCID50/swab of gamma irradiated SARS-CoV-2 virus, meeting the acceptable analytical sensitivity outlined by in World Health Organization target product profile. The open-source architecture presented in this manuscript provides a template for manufacturers around the globe to rapidly design a SARS-CoV2 antigen test.

scholarly journals OCORRÊNCIA DO HERBICIDA TEBUTHIURON NA ÁGUA SUBTERRÂNEA DA MICROBACIA DO CÓRREGO ESPRAIADO, RIBEIRÃO PRETO - SP

2001 ◽  
Vol 11 ◽  
Author(s):  
MARCO ANTONIO FERREIRA GOMES ◽  
CLÁUDIO A. SPADOTTO ◽  
VERA LÚCIA LANCHOTTE
Keyword(s):  
Biological Activity ◽  
Low Temperature ◽  
Water Samples ◽  
Critical Level ◽  
World Health ◽  
Contamination Risk ◽  
Soil Mobility ◽  
Drinkable Water ◽  
Health Organization ◽  
Monitoring Area

Pretendeu-se mostrar que o herbicida Tebuthiuron, selecionado entre outros usados na cultura de cana-de-açúcar, oferece risco de contaminação para a água subterrânea em função de suas características físico-químicas, principalmente, quando aplicado em áreas de recarga direta de aqüíferos consideradas de alta vulnerabilidade natural. Assim, efetuou-se monitoramento do referido herbicida no período compreendido entre 1995 e 1999, coletando amostras de água de poço semi-artesiano, com 53 metros de profundidade, localizado na microbacia do Córrego Espraiado, município de Ribeirão Preto/SP, Brasil, no qual tem sido freqüente o uso do produto em questão. Para efeito de testemunha da amostra de água foi considerado um poço semi-artesiano de profundidade semelhante, localizado cerca de três quilômetros de distância do poço objeto de monitoramento. Os resultados obtidos mostraram que o Tebuthiuron está presente em todas as amostras analisadas, embora em concentrações abaixo do nível crítico para padrão de potabilidade, conforme os limites mais restritivos estabelecidos pela Organização Mundial de Saúde (para os pesticidas em uso é de 0,1 µg/L por pesticida e de 0,5 µg/L para pesticidas totais). Mesmo com os baixos valores de concentração encontrados fica evidente que o Tebuthiuron está atingindo a água subterrânea podendo aumentar sua concentração pela existência de condições ambientais favoráveis à preservação da molécula em profundidade (tais como baixa temperatura, baixa atividade biológica e ausência de luz). Caso o nível crítico seja atingido, o risco de contaminação poderia ser minimizado por meio da substituição do Tebuthiuron por outro herbicida com menor mobilidade no perfil do solo. OCCURRENCE OF THE HERBICIDE TEBUTHIURON IN GROUNDWATER OF ESPRAIADO CATCHMENT RIBEIRAO PRETO - SP (BRASIL) Abstract The herbicide Tebuthiuron, selected among others utilized in sugar-cane crop, shows groundwater contamination risk due to its physicochemical properties, mainly, when applied in direct recharge areas of aquifers considered of high natural vulnerability. In this context, the monitoring of this herbicide in the period of 1995 through 1999 was realized, by collecting water samples of aquifers 53 m depht, located in Espraiado catchment, Ribeirao Preto/SP (Brazil) in which the product has been extensively used. For blank assays it was utilized water samples collected similarly 3 Km away from the monitoring area. The results obtained showed that Tebuthiuron is present in all analyzed samples. Although in lower concentrations of the critical level for drinkable water, following the restrictive limits established by World Health Organization (for pesticides in use is 0,1 µg/L by pesticide and of 0,5 µg/L for total pesticides). Even if the low concentration values found it is evident that the Tebuthiuron affects the groundwater, and could enhance its concentration by favorable ambiental conditions for molecule preservation in deep water (such as low temperature, low biological activity and absence of light). The present scenary reflects contamination risk in case of reaching the critical level, which could only be minimized by the substitution of Thebuthiuron for other herbicide with lower soil mobility.

scholarly journals Physico-chemical quality of drinking water in the Njoro sub-county in Kenya

2018 ◽  
Vol 8 (3) ◽  
pp. 497-507
Author(s):  
Philip Ruciaka Kirianki ◽  
Edward Muchiri ◽  
Natasha Potgieter
Keyword(s):  
Drinking Water ◽  
Water Samples ◽  
Water Source ◽  
World Health ◽  
Water Shortages ◽  
Storage Container ◽  
Standard Assessment ◽  
Physico Chemical ◽  
Study Support ◽  
Health Organization

Abstract Njoro sub-county in Kenya suffers from constant water shortages causing the residents to rely on both improved and unimproved water sources in the area. The households in the sub-county also use different household storage containers to store drinking water in times when water is not readily available. This study was therefore undertaken to assess selective physico-chemical parameters of water used by the population for drinking purposes using standard assessment methods. A total of 372 water source samples and 162 storage container water samples were tested over a period of three months. Turbidity (0.70–273.85 NTU), iron (0.7–2.10 mg/L), fluoride (0.15–4.01 mg/L), manganese (0.01–0.37 mg/L), and nitrate (0.09–27.90 mg/L) levels in water samples were generally higher than the Kenya Bureau of Standards (KEBS) and/or the World Health Organization (WHO) water quality recommendations for safe drinkable water. The results from this study support the need for continuous monitoring and treating drinking water at the points of collection and of consumption to minimize the long-term health effects on communities consuming this water.

scholarly journals Water Quality of the Trstionica River (Bosnia and Herzegovina)

2020 ◽  
Vol 69 (7-8) ◽  
pp. 371-376
Author(s):  
Šuhreta Delibašić ◽  
Jasna Huremović ◽  
Sabina Žero ◽  
Sabina Gojak-Salimović
Keyword(s):  
Water Quality ◽  
Bosnia And Herzegovina ◽  
Limit Of Detection ◽  
Weather Conditions ◽  
Ion Exchange Resin ◽  
World Health ◽  
Mean Values ◽  
Significant Difference ◽  
Health Organization

The present study was conducted to investigate the water quality of the Trstionica River, Bosnia and Herzegovina. The physicochemical properties (temperature, pH, conductivity, total solids after evaporation at 105 °C), content of metals (calcium (Ca), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), sodium (Na), nickel (Ni), lead (Pb) and zinc (Zn)), and anions (chloride (Cl–), and phosphate (PO43–)) were determined in water samples collected at seven locations during two sampling periods: unstable weather conditions (precipitation), and stable weather conditions (without precipitation). There was a significant difference in the content of individual parameters in the river water depending on the sampling time. For determination of metals concentrations, which were below the limit of detection, a preconcentration method using an ion-exchange resin was applied. The metals concentrations during the rainy day were in the order Ca > Mg > Na > Fe > Cu > Zn > Pb > Mn with mean values of 343, 6.03, 1.94, 0.18, 0.20, 0.03, 0.02, 0.01 mg dm–3, respectively, and during stable weather conditions: Ca > Mg > Na > Cu > Fe > Mn > Zn with mean values of 288, 7.62, 2.38, 0.11, 0.10, 0.01, 0.01 mg dm–3, respectively. Cd, Cr, and Ni concentrations were below limit of detection in both cases. Obtained values were compared with World Health Organization (WHO) regulations. The results showed that the Trstionica River in the investigated part of the stream meets most of the parameters required by the regulations. The correlation between analysed parameters was assessed, as well. Based on the calculated water quality index values, the water of Trstionica River falls into the category of excellent water.

Investigation of the physicochemical and pharmacognostical properties of Anzaroot (The manna of Astragalus sarcocola Dymock.) according to the World Health Organization

2020 ◽  
Vol 42 (5) ◽  
pp. 564-571
Author(s):  
Hadi Esmaeeli ◽  
Ali Davoodi ◽  
Masoud Azadbakht ◽  
Mohammad Azadbakht
Keyword(s):  
Traditional Medicine ◽  
World Health Organization ◽  
Pharmaceutical Products ◽  
Water Soluble ◽  
World Health ◽  
Flavonoid Content ◽  
Therapeutic Properties ◽  
The Common ◽  
Health Organization ◽  
Scientific Name

Background: Anzaroot is a manna produced from Astragalus sarcocola Dymock (Family Leguminosae) that is widely distributed in Fars, Kerman, Baluchestan and Hormozgan in Iran. Since the study of the physicochemical properties and quality control (QC) of herbal materials results in the validation and standardization for clinical uses, in accordance with World Health Organization (WHO) guidelines, it is necessary to carry out for Anzaroot which has indication in traditional medicine. Methods: Anzaroot was identified and determinated scientific name by a systematic specialist after purchasing from Niak pharmaceutical co. in gorgan. Physicochemical and pharmacognostical properties of Anzaroot have been determinated According to the WHO guidlines. Results: Anzaroot is a very bitter, crisp and fragile manna and non-stick in dry state, which is seen as separate binary grains under the microscope. The moisture content, foreign matter, sucrose content, total ash and water-soluble ash were reported 5.25 ± 0.2, 2.8 ± 0.2, 12.09 ± 0.04, 9.8 ± 0.5 and 2.9±0.15, respectively. It has significant foaming index, 72% Solublity in water and less than 50% in 96% ethanol and not swelling index. The levels of lead, mercury and cadmium were 0.0006, 0.0002 and 0.0007 ppm and total flavonoid content was reported 18.61 μg/ml with respect to standard Quercetin at 415 nm. Conclusion: This study can be a novel idea for the discovery or development of pharmaceutical products based on Anzaroot of Iran and its diverse therapeutic properties, such as the common cold, contusion, and bone fracture in traditional medicine.

scholarly journals Assessment of Some Heavy Metals in Drinking Water Samples of Tunceli, Turkey

2011 ◽  
Vol 8 (1) ◽  
pp. 276-280 ◽  
Author(s):  
Olcay Kaplan ◽  
Nuran Cikcikoglu Yildirim ◽  
Numan Yildirim ◽  
Nilgun Tayhan
Keyword(s):  
Heavy Metals ◽  
Drinking Water ◽  
Water Samples ◽  
World Health ◽  
Environment Protection ◽  
Protection Agency ◽  
Supply Networks ◽  
Health Organization ◽  
The City ◽  
Drinking Water Samples

The drinking water quality is associated with the conditions of the water supply networks, the pollution and the contamination of groundwater with pollutants of both anthropogenic and natural origin. In this study, water samples were taken from four different waterworks in Tunceli, Turkey and heavy metals concentrations (As, Cu, Cd, Cr, Pb, Ni and Hg) were measured. Four sampling sites were pre-defined in different locations of the city. The obtained results showed that, the heavy metals concentrations in water samples did not exceed the values of WHO (World Health Organization), EC (Europe Community), EPA (Environment Protection Agency) and TSE-266 (Turkish Standard) guidelines.

scholarly journals A Sensitive Near-Infrared Fluorescent Probe for Detecting Heavy Metal Ag+ in Water Samples

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 247 ◽  
Author(s):  
Yawen Zhang ◽  
Aiying Ye ◽  
Yuewei Yao ◽  
Cheng Yao
Keyword(s):  
Fluorescent Probe ◽  
Water Samples ◽  
Near Infrared ◽  
Color Change ◽  
World Health ◽  
Naked Eye ◽  
Real Water Samples ◽  
Frequent Use ◽  
The World ◽  
Health Organization

Silver is a common catalyst in industrial production, and the frequent use of Ag+ can cause water pollution. Thus, the detection of Ag+ in the environment is necessary to determine the level of pollution from silver. In this work, we designed a new, highly selective near-infrared (NIR) fluorescent probe QCy to detect Ag+. The probe exhibits “turn-off” fluorescence quenching responses at 760 nm towards Ag+ over other relevant cations, with outstanding sensitivity and a low detection limit (0.03 µM), which is considerably lower than the standard of the World Health Organization (WHO) for drinking water (0.9 µM). Meanwhile, QCy showed a very good linearity at a low concentration of Ag+ with a ‘naked eye’ visible color change of solution from blue to red. The probe has been applied successfully for the detection of Ag+ in real water samples.

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