Colorimetric Detection of Chromium(VI) Ions in Water Using Unfolded-Fullerene Carbon Nanoparticles

Water pollution caused by hexavalent chromium (Cr(VI)) ions represents a serious hazard for human health due to the high systemic toxicity and carcinogenic nature of this metal species. The optical sensing of Cr(VI) through specifically engineered nanomaterials has recently emerged as a versatile strategy for the application to easy-to-use and cheap monitoring devices. In this study, a one-pot oxidative method was developed for the cage opening of C60 fullerene and the synthesis of stable suspensions of N-doped carbon dots in water–THF solutions (N-CDs-W-THF). The N-CDs-W-THF selectively showed variations of optical absorbance in the presence of Cr(VI) ions in water through the arising of a distinct absorption band peaking at 550 nm, i.e., in the transparency region of pristine material. Absorbance increased linearly, with the ion concentration in the range 1–100 µM, thus enabling visual and ratiometric determination with a limit of detection (LOD) of 300 nM. Selectivity and possible interference effects were tested over the 11 other most common heavy metal ions. The sensing process occurred without the need for any other reactant or treatment at neutral pH and within 1 min after the addition of chromium ions, both in deionized and in real water samples.

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Humic Acid Functionalized - Silver Nanoparticles as Nanosensor for Colorimetric Detection of Copper (II) Ions in Aqueous Solutions

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.831.142 ◽

2020 ◽

Vol 831 ◽

pp. 142-150

Author(s):

Edgar Clyde R. Lopez ◽

Michael Angelo Zafra ◽

Jon Nyner L. Gavan ◽

Emil David A. Villena ◽

Francis Eric P. Almaquer ◽

...

Keyword(s):

Silver Nanoparticles ◽

Humic Acid ◽

Aqueous Solutions ◽

Limit Of Detection ◽

Colorimetric Detection ◽

Hydrodynamic Diameter ◽

Limit Of Quantification ◽

Local Surface Plasmon Resonance ◽

Optical Absorbance ◽

Absorbance Spectra

Humic acid - functionalized silver nanoparticles (HA-AgNPs) were successfully synthesized and used to detect Cu (II) ions in aqueous solutions. The HA-AgNPs was shown to have an average hydrodynamic diameter of 101.4 nm and a polydispersity index of 0.447. The absorbance spectra of HA-AgNPs showed the characteristic local surface plasmon resonance (LSPR) peak of AgNPs at 408.3 nm. Addition of Cu (II) in the HA-AgNPs led to their agglomeration as evidenced by the change in their surface morphology and their corresponding optical absorbance spectra. The synthesized HA-AgNPs showed a strong linear response for Cu (II) concentrations in the range of 0.00 – 1.25 mM with a limit of detection (LoD) of 4.4428 ± 0.1091 mg L-1, a limit of quantification (LoQ) of 14.8094 ± 0.3636 mg L-1, and a limit of blank (LoB) of 0.1214 ± 0.0065 mg L-1. Statistical analysis showed that this calibration curve could be used to quantify Cu (II) concentrations within a 95% confidence level. Furthermore, HA-AgNPs was found to be selective for Cu (II) detection based on the selectivity study against common metal ions found in drinking water. This shows that the synthesized HA-AgNPs can be used as an environment-friendly colorimetric nanosensor for rapid and point-of-need quantification of Cu (II) ions in aqueous media.

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A Point of Care Lateral Flow Assay for Rapid and Colorimetric Detection of Interleukin 6 and Perspectives in Bedside Diagnostics

Journal of Clinical and Medical Research ◽

10.37191/mapsci-2582-4333-2(3)-032 ◽

2020 ◽

Author(s):

Carla Eiras

Keyword(s):

Interleukin 6 ◽

Limit Of Detection ◽

Inflammatory Diseases ◽

Point Of Care ◽

Colorimetric Detection ◽

Lateral Flow ◽

Lateral Flow Assay ◽

Aggregation Assay ◽

Before And After ◽

Bedside Diagnosis

Interleukin-6 (IL-6) is a multifunctional cytokine and high bloodstream levels of which have been associated with severe inflammatory diseases, such as dengue fever, sepsis, various cancers, and visceral leishmaniasis (VL). Rapid tests for the quantification of IL-6 would be of great assistance for the bedside diagnosis and treatment of diseases such as VL. We have developed a lateral flow assay (LFA) for rapid and colorimetric IL-6 detection, consisting of anti-IL-6 antibodies conjugated to gold nanoparticles (AuNPs). The optimal concentration of anti-IL-6 used in the conjugate was determined to be 800.0 μg/mL, based on an aggregation assay using LFA. A linear relationship between IL-6 standard concentration and color intensity was observed after 20 min, with a linear range between 1.25 ng/mL and 9,000 ng/mL. The limit of detection for this method was estimated a t0.38 ng/mL. The concentration of IL-6 in five patients with severe VL was measured using LFA, and the results were consistent with those obtained using the cytometric bead array (CBA) method. A thorough analysis of the LFA membranes’ surface morphology, before and after sample contact, was performed using atomic force microscopy (AFM).The prototype described here is still being tested and improved, but this LFA will undoubtedly be of great help in the clinical quantification of IL-6.

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A Point of Care Lateral Flow Assay for Rapid and Colorimetric Detection of Interleukin 6 and Perspectives in Bedside Diagnostics

Journal of Clinical and Medical Research ◽

10.37191/mapsci-2582-4333-2(2)-032 ◽

2020 ◽

Author(s):

Carla Eiras

Keyword(s):

Interleukin 6 ◽

Limit Of Detection ◽

Inflammatory Diseases ◽

Point Of Care ◽

Colorimetric Detection ◽

Lateral Flow ◽

Lateral Flow Assay ◽

Aggregation Assay ◽

Before And After ◽

Bedside Diagnosis

Interleukin-6 (IL-6) is a multifunctional cytokine and high bloodstream levels of which have been associated with severe inflammatory diseases, such as dengue fever, sepsis, various cancers, and visceral leishmaniasis (VL). Rapid tests for the quantification of IL-6 would be of great assistance for the bedside diagnosis and treatment of diseases such as VL. We have developed a lateral flow assay (LFA) for rapid and colorimetric IL-6 detection, consisting of anti-IL-6 antibodies conjugated to gold nanoparticles (AuNPs). The optimal concentration of anti-IL-6 used in the conjugate was determined to be 800.0 μg/mL, based on an aggregation assay using LFA. A linear relationship between IL-6 standard concentration and color intensity was observed after 20 min, with a linear range between 1.25 ng/mL and 9,000 ng/mL. The limit of detection for this method was estimated at a t0.38 ng/mL. The concentration of IL-6 in five patients with severe VL was measured using LFA, and the results were consistent with those obtained using the cytometric bead array (CBA) method. A thorough analysis of the LFA membranes’ surface morphology, before and after sample contact, was performed using atomic force microscopy (AFM). The prototype described here is still being tested and improved, but this LFA will undoubtedly be of great help in the clinical quantification of IL-6.

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A rapid, accurate, scalable, and portable testing system for COVID-19 diagnosis

Nature Communications ◽

10.1038/s41467-021-23185-x ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Guanhua Xun ◽

Stephan Thomas Lane ◽

Vassily Andrew Petrov ◽

Brandon Elliott Pepa ◽

Huimin Zhao

Keyword(s):

Limit Of Detection ◽

Low Cost ◽

High Volume ◽

N Gene ◽

Testing System ◽

Target Sequence ◽

One Pot ◽

Sequence Detection ◽

Highly Sensitive ◽

Speed Accuracy

AbstractThe need for rapid, accurate, and scalable testing systems for COVID-19 diagnosis is clear and urgent. Here, we report a rapid Scalable and Portable Testing (SPOT) system consisting of a rapid, highly sensitive, and accurate assay and a battery-powered portable device for COVID-19 diagnosis. The SPOT assay comprises a one-pot reverse transcriptase-loop-mediated isothermal amplification (RT-LAMP) followed by PfAgo-based target sequence detection. It is capable of detecting the N gene and E gene in a multiplexed reaction with the limit of detection (LoD) of 0.44 copies/μL and 1.09 copies/μL, respectively, in SARS-CoV-2 virus-spiked saliva samples within 30 min. Moreover, the SPOT system is used to analyze 104 clinical saliva samples and identified 28/30 (93.3% sensitivity) SARS-CoV-2 positive samples (100% sensitivity if LoD is considered) and 73/74 (98.6% specificity) SARS-CoV-2 negative samples. This combination of speed, accuracy, sensitivity, and portability will enable high-volume, low-cost access to areas in need of urgent COVID-19 testing capabilities.

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Facile Hydrothermal and Solvothermal Synthesis and Characterization of Nitrogen-Doped Carbon Dots from Palm Kernel Shell Precursor

Applied Sciences ◽

10.3390/app11041630 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1630

Author(s):

Yakubu Newman Monday ◽

Jaafar Abdullah ◽

Nor Azah Yusof ◽

Suraya Abdul Rashid ◽

Rafidah Hanim Shueb

Keyword(s):

Carbon Dots ◽

Batch Reactor ◽

Average Particle Size ◽

Research Work ◽

Palm Kernel ◽

Average Particle ◽

One Pot ◽

Palm Kernel Shell ◽

Doped Carbon Dots ◽

Nitrogen Doped Carbon

Carbon dots (CDs), a nanomaterial synthesized from organic precursors rich in carbon content with excellent fluorescent property, are in high demand for many purposes, including sensing and biosensing applications. This research focused on preparing CDs from natural and abundant waste, palm kernel shells (PKS) obtained from palm oil biomass, aiming for sensing and biosensing applications. Ethylenediamine and L-phenylalanine doped CDs were produced via the hydrothermal and solvothermal methods using one-pot synthesis techniques in an autoclave batch reactor. The as-prepared N-CDs shows excellent photoluminescence (PL) property and a quantum yield (QY) of 13.7% for ethylenediamine (EDA) doped N-CDs (CDs-EDA) and 8.6% for L-phenylalanine (L-Ph) doped N-CDs (CDs-LPh) with an excitation/emission wavelength of 360 nm/450 nm. The transmission electron microscopy (TEM) images show the N-CDs have an average particle size of 2 nm for both CDs. UV-Visible spectrophotometric results showed C=C and C=O transition. FTIR results show and confirm the presence of functional groups, such as -OH, -C=O, -NH2 on the N-CDs, and the X-ray diffraction pattern showed that the N-CDs were crystalline, depicted with sharp peaks. This research work demonstrated that palm kernel shell biomass often thrown away as waste can produce CDs with excellent physicochemical properties.

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Optical, electrochemical and photocatalytic properties of cobalt doped CsPbCl3 nanostructures: a one-pot synthesis approach

Scientific Reports ◽

10.1038/s41598-021-95088-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Aadil Ahmad Bhat ◽

Shakeel Ahmad Khandy ◽

Ishtihadah Islam ◽

Radha Tomar

Keyword(s):

Optical Properties ◽

Visible Light ◽

Active Material ◽

Blue Emission ◽

Structural Features ◽

Ion Concentration ◽

Photocatalytic Properties ◽

Charge Storage ◽

Cobalt Doping ◽

One Pot

AbstractThe present manuscript aims at the synthesis of cesium based halide perovskite nanostructures and the effect of cobalt doping on the structural, optical, lumnisent, charge storage and photocatalytic properties. In a very first attempt, we report the solvothermal synthesis of Co doped CsPbCl3 nanostructures under subcritical conditions. The structural features were demonstrated by X-ray diffraction (XRD) Surface morphology determined cubic shape of the synthesized particles. Doping is an excellent way to modify the properties of host material in particular to the electronic structure or optical properties. Incorporation of Co2+ ions in the perovskite structure tunes the optical properties of the nanostructures making this perovskite a visible light active material (Eg = 1.6 eV). This modification in the optical behaviour is the result of size effect, the crystallite size of the doped nanostructures increases with cobalt doping concentration. Photolumniscance (PL) study indicated that CsPbCl3 exhibited Blue emission. Thermogravametric analysis (TGA) revealed that the nanostructures are quite stable at elavated temperatures. The electrochemical performance depicts the pseudocapacative nature of the synthesized nanostructures and can used for charge storage devices. The charge storage capability showed direct proportionality with cobalt ion concentration. And Finally the photocatalytic performance of synthesized material shows superior catalytic ability degrading 90% of methylene blue (MB) dye in 180 min under visible light conditions.

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Highly sensitive and selective colorimetric detection of dual metal ions (Hg2+ and Sn2+) in water: an eco-friendly approach

RSC Advances ◽

10.1039/d0ra09926k ◽

2021 ◽

Vol 11 (24) ◽

pp. 14700-14709

Author(s):

Rintumoni Paw ◽

Moushumi Hazarika ◽

Purna K. Boruah ◽

Amlan Jyoti Kalita ◽

Ankur K. Guha ◽

...

Keyword(s):

Metal Ions ◽

Ag Nanoparticles ◽

Limit Of Detection ◽

Colorimetric Detection ◽

Garlic Extract ◽

Selective Detection ◽

Highly Sensitive ◽

Dual Metal

Synthesis of Ag nanoparticles using Allin based garlic extract for highly sensitive and selective detection of metal ions Hg2+ and Sn2+ in water. The limit of detection (LoD) for Hg2+ and Sn2+ ions were found as 15.7 nM and 11.25 nM respectively.

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Radiological Assessment of Indoor Radon and Thoron Concentrations and Indoor Radon Map of Dwellings in Mashhad, Iran

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18010141 ◽

2020 ◽

Vol 18 (1) ◽

pp. 141

Author(s):

Mohammademad Adelikhah ◽

Amin Shahrokhi ◽

Morteza Imani ◽

Stanislaw Chalupnik ◽

Tibor Kovács

Keyword(s):

Limit Of Detection ◽

Indoor Radon ◽

Absolute Error ◽

Soil Gas ◽

Indoor Radon Concentration ◽

Soil Gas Radon ◽

Distance Weighting ◽

The City ◽

Monitoring Devices ◽

Radon Concentrations

A comprehensive study was carried out to measure indoor radon/thoron concentrations in 78 dwellings and soil-gas radon in the city of Mashhad, Iran during two seasons, using two common radon monitoring devices (NRPB and RADUET). In the winter, indoor radon concentrations measured between 75 ± 11 to 376 ± 24 Bq·m−3 (mean: 150 ± 19 Bq m−3), whereas indoor thoron concentrations ranged from below the Lower Limit of Detection (LLD) to 166 ± 10 Bq·m−3 (mean: 66 ± 8 Bq m−3), while radon and thoron concentrations in summer fell between 50 ± 11 and 305 ± 24 Bq·m−3 (mean 115 ± 18 Bq m−3) and from below the LLD to 122 ± 10 Bq m−3 (mean 48 ± 6 Bq·m−3), respectively. The annual average effective dose was estimated to be 3.7 ± 0.5 mSv yr−1. The soil-gas radon concentrations fell within the range from 1.07 ± 0.28 to 8.02 ± 0.65 kBq·m−3 (mean 3.07 ± 1.09 kBq·m−3). Finally, indoor radon maps were generated by ArcGIS software over a grid of 1 × 1 km2 using three different interpolation techniques. In grid cells where no data was observed, the arithmetic mean was used to predict a mean indoor radon concentration. Accordingly, inverse distance weighting (IDW) was proven to be more suitable for predicting mean indoor radon concentrations due to the lower mean absolute error (MAE) and root mean square error (RMSE). Meanwhile, the radiation health risk due to the residential exposure to radon and indoor gamma radiation exposure was also assessed.

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Synthesis of catalytically active multielement-doped carbon dots and application for colorimetric detection of glucose

Sensors and Actuators B Chemical ◽

10.1016/j.snb.2017.09.067 ◽

2018 ◽

Vol 255 ◽

pp. 2601-2607 ◽

Cited By ~ 38

Author(s):

Bin Wang ◽

Feng Liu ◽

Yuanya Wu ◽

Yanfen Chen ◽

Bo Weng ◽

...

Keyword(s):

Carbon Dots ◽

Colorimetric Detection ◽

Catalytically Active ◽

Doped Carbon Dots

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SEPARATION OF CHROM (VI) FROM ELECTROPLATING WASTE USING POLYMER INCLUSION MEMBRANE (PIM) METHOD

ALCHEMY Jurnal Penelitian Kimia ◽

10.20961/alchemy.13.1.4562.119-132 ◽

2017 ◽

Vol 13 (1) ◽

pp. 119 ◽

Cited By ~ 1

Author(s):

Muhammad Cholid Djunaidi ◽

Khabibi Khabibi ◽

Rizka Nurfitriana

Keyword(s):

Metal Ion ◽

Membrane Surface ◽

Separation Process ◽

Ion Concentration ◽

Aliquat 336 ◽

Nacl Solution ◽

Chromium Ion ◽

Chromium Vi ◽

Base Polymer ◽

Feed Phase

Research of chromium (VI) separation has been done using polymer inclusion membrane (PIM) method. This study aims to generate PIM, separate the metal ion chromium (VI) using PIM and determine the effect of the concentration of the feed phase, the thickness of the membrane and the amount of usage of the membrane for ion chromium (VI) diffusion.Polymer inclusion membrane (PIM) was made by mixing Aliquat 336-TBP as carrier compounds, PVC as the base polymer, DBE as a plasticizer and THF as a solvent. PIM membrane was placed between the source of analyte as a feed phase and result of the separation as a receiver phase. Feed phase was electroplating waste metal containing chromium (VI) at pH 4, while the receiver phase was a 2 N NaCl solution with a pH 6.7. The change of variables in this study were the concentration of the feed phase at various dilution i.e., 100x, 50x and 10x, the thickness of the membrane i.e., 25 μm, 20 μm and 10 μm, and the time of membrane using i.e., 1, 2 and 3 times. The concentration of chromium (VI) diffused after separation process was analyzed by atomic absorption spectroscopy (AAS). The stability of membrane was observed by analyzing the presence of membrane’s component in the feed phase and in the receiver phase. The analysis was conducted by UV-Vis spectrophotometry. Meanwhile, scanning electron microscopy (SEM) analysis was used to determine the morphology of membrane surface.The results showed that the chromium ion concentration diffused from the feed phase was 99.24%, meanwhile the 85.88% of it diffused to the receiving phase. The highest Cr(VI) ions diffusion was occured at the first use of PIM membrane with a thickness of 10 μm and the concentration of the feed phase was 10.55 ppm (resulted from 100 times dilution). Therefore, it can be concluded that the diffusion of chromium (VI) ion was influenced by the concentration of feed phase, the thickness of membrane and the number of membrane application.

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