scholarly journals Ultrafast and Energy-saving Synthesis of Nitrogen and Chlorine Co-doped Carbon Nanodots via Neutralization Heat for Selective Detection of Cr(VI) in Aqueous Phase

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3416 ◽  
Author(s):  
Qin Hu ◽  
Tao Li ◽  
Lu Gao ◽  
Xiaojuan Gong ◽  
Shengqi Rao ◽  
...  
Keyword(s):  
Energy Saving ◽  
Water Samples ◽  
Fluorescence Probe ◽  
Limit Of Detection ◽  
Inner Filter Effect ◽  
Fluorescence Method ◽  
Carbon Nanodots ◽  
Selective Detection ◽  
Relative Standard ◽  
Co Doped

In this work, it is presented for the first time that nitrogen and chlorine co-doped carbon nanodots (N,Cl-CDs) were synthesized by simply mixing glucose, concentrated hydrochloric acid (HCl), and 1,2-ethylenediamine (EDA). No external heat was employed; the neutralization reaction served as the heat source. The glucose served as the carbon source while EDA and HCl were the N and Cl dopants, respectively. The fluorescence of N,Cl-CDs was adequately quenched by hexavalent chromium Cr(VI) based on a combination of dynamic quenching and inner filter effect (IFE). Accordingly, an efficient N,Cl-CDs-based fluorescence probe was established for sensitive and selective detection of Cr(VI). The proposed fluorescence sensor provides a linear recognition range for Cr(VI) determination from 3 to 40 µM with a limit of detection (LOD) of 0.28 µM (14.6 µg/L). The proposed fluorescence method was successfully utilized to detect Cr(VI) in different water samples with satisfactory results. The spike recoveries vary from 97.01% to 103.89% with relative standard deviations (RSDs) of less than 0.82%. This work highlights the development of a simple, ultrafast, and energy-saving one-step synthetic route to fabricate N,Cl-CDs for highly selective and sensitive detection of Cr(VI) in real water samples. It is anticipated that the proposed fluorescence method could be further explored and widely used for Cr(VI) detection in the environmental industry.

scholarly journals Determination of cobalt in water samples by atomic absorption spectrometry after pre-concentration with a simple ionic liquid-based dispersive liquid-liquid micro-extraction methodology

2010 ◽  
Vol 8 (3) ◽  
pp. 617-625 ◽  
Author(s):  
Hossein Abdolmohammad-Zadeh ◽  
Elnaz Ebrahimzadeh
Keyword(s):  
Ionic Liquid ◽  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Water Samples ◽  
Limit Of Detection ◽  
Absorption Spectrometry ◽  
Experimental Conditions ◽  
Flame Atomic Absorption ◽  
Relative Standard

AbstractA rapid dispersive liquid-liquid micro-extraction (DLLME) methodology based on the application of 1-hexylpyridinium hexafluorophosphate [C6py][PF6] ionic liquid (IL) as an extractant solvent was applied for the pre-concentration of trace levels of cobalt prior to determination by flame atomic absorption spectrometry (FAAS). 1-Phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) was employed as a chelator forming a Co-PMBP complex to extract cobalt ions from aqueous solution into the fine droplets of [C6py][PF6]. Some effective factors that influence the micro-extraction efficiency include the pH, the PMBP concentration, the amount of ionic liquid, the ionic strength, the temperature and the centrifugation time which were investigated and optimized. In the optimum experimental conditions, the limit of detection (3s) and the enrichment factor were 0.70 µg L−1 and 60, respectively. The relative standard deviation (RSD) for six replicate determinations of 50 µg L−1 Co was 2.36%. The calibration graph using the pre-concentration system was linear at levels 2–166 µg L−1 with a correlation coefficient of 0.9982. The applicability of the proposed method was evaluated by the determination of trace amounts of cobalt in several water samples.

scholarly journals Development of a Cloud-Point Extraction Method for Cobalt Determination in Natural Water Samples

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Mohammad Reza Jamali ◽  
Mohammad Gholinezhad ◽  
Saiedeh Balarostaghi ◽  
Reyhaneh Rahnama ◽  
Seyed Hojjat Allah Rahimi
Keyword(s):  
Cloud Point ◽  
Water Samples ◽  
Cloud Point Extraction ◽  
Limit Of Detection ◽  
Cobalt Content ◽  
Cobalt Ions ◽  
Flame Atomic Absorption ◽  
Relative Standard ◽  
Separation And Preconcentration ◽  
Triton X

A new, simple, and versatile cloud-point extraction (CPE) methodology has been developed for the separation and preconcentration of cobalt. The cobalt ions in the initial aqueous solution were complexed with 4-Benzylpiperidinedithiocarbamate, and Triton X-114 was added as surfactant. Dilution of the surfactant-rich phase with acidified ethanol was performed after phase separation, and the cobalt content was measured by flame atomic absorption spectrometry. The main factors affecting CPE procedure, such as pH, concentration of ligand, amount of Triton X-114, equilibrium temperature, and incubation time were investigated and optimized. Under the optimal conditions, the limit of detection (LOD) for cobalt was 0.5 μg L-1, with sensitivity enhancement factor (EF) of 67. Calibration curve was linear in the range of 2–150 μg L-1, and relative standard deviation was 3.2% (c=100 μg L-1;n=10). The proposed method was applied to the determination of trace cobalt in real water samples with satisfactory analytical results.

scholarly journals Use of Dispersive Liquid-Liquid Microextraction and UV-Vis Spectrophotometry for the Determination of Cadmium in Water Samples

2014 ◽  
Vol 2014 ◽  
pp. 1-4 ◽  
Author(s):  
J. Pérez-Outeiral ◽  
E. Millán ◽  
R. Garcia-Arrona
Keyword(s):  
Water Samples ◽  
Limit Of Detection ◽  
Experimental Conditions ◽  
Cadmium Determination ◽  
A Value ◽  
Relative Standard ◽  
Potential Applicability ◽  
Dispersive Liquid Liquid Microextraction ◽  
Liquid Microextraction

A simple and inexpensive method for cadmium determination in water using dispersive liquid-liquid microextraction and ultraviolet-visible spectrophotometry was developed. In order to obtain the best experimental conditions, experimental design was applied. Calibration was made in the range of 10–100 μg/L, obtaining good linearity (R2 = 0.9947). The obtained limit of detection based on calibration curve was 8.5 μg/L. Intra- and interday repeatability were checked at two levels, obtaining relative standard deviation values from 9.0 to 13.3%. The enrichment factor had a value of 73. Metal interferences were also checked and tolerable limits were evaluated. Finally, the method was applied to cadmium determination in real spiked water samples. Therefore, the method showed potential applicability for cadmium determination in highly contaminated liquid samples.

scholarly journals A Sensitive Impedimetric Aptasensor Based on Carbon Nanodots Modified Electrode for Detection of 17ß-Estradiol

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1346 ◽  
Author(s):  
Mohd Hazani Mat Zaid ◽  
Jaafar Abdullah ◽  
Normazida Rozi ◽  
Aliff Aiman Mohamad Rozlan ◽  
Sharina Abu Hanifah
Keyword(s):  
Water Samples ◽  
Electrochemical Impedance ◽  
Carbon Nanodots ◽  
Visible Absorption ◽  
Transmission Electron ◽  
Relative Standard ◽  
Before And After ◽  
Average Recovery Rate ◽  
Aptamer Probe ◽  
Eis Measurements

A simple and sensitive aptasensor based on conductive carbon nanodots (CDs) was fabricated for the detection of 17ß-Estradiol (E2). In the present study, the hydrothermal synthesis of carbon nanodots was successfully electrodeposited on a screen-printed electrode (SPE) as a platform for immobilization of 76-mer aptamer probe. The morphology and structure of the nanomaterial were characterized by UV-visible absorption spectra, Fluorescence spectra, Transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). Moreover, cyclic voltammetry and electrochemical impedance spectroscopy were used to investigate the electrochemical performance of the prepared electrodes. Subsequently, impedimetric (EIS) measurements were employed to investigate the relative impedances changes before and after E2 binding, which results in a linear relationship of E2 concentration in the range of 1.0 × 10−7 to 1.0 × 10 −12 M, with a detection limit of 0.5 × 10−12 M. Moreover, the developed biosensor showed high selectivity toward E2 and exhibited excellent discrimination against progesterone (PRG), estriol (E3) and bisphenol A (BPA), respectively. Moreover, the average recovery rate of spiked river water samples with E2 ranged from 98.2% to 103.8%, with relative standard deviations between 1.1% and 3.8%, revealing the potential application of the present biosensor for E2 detection in water samples.

scholarly journals Extraction and Determination of Oxymatrine Pesticide in Environmental Sample and in its Formulation using High-Performance Liquid Chromatography

2020 ◽  
Vol 8 (2) ◽  
pp. 1-7
Author(s):  
Ihsan M. Shaheed ◽  
Saadiyah A. Dhahir
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Water Samples ◽  
High Performance ◽  
Limit Of Detection ◽  
Limit Of Quantification ◽  
Chromatography Method ◽  
Relative Standard ◽  
Dispersive Liquid Liquid Microextraction

The quinolizindine alkaloid compound, oxymatrine pesticide, was analysis in the river water samples collected from different agriculture areas in the Iraqi city of Kerbala and also in its formulation using developed reverse-phase high-performance liquid chromatography method. Acetonitrile:methanol (60:40 v/v) was chosen as mobile phase at pH (7.0), flow rate 0.5 mL/min, and 20 µL as volume injection. Modified ecological-friendly method, dispersive liquid-liquid microextraction, was used for the extraction of oxymatrine from water samples. Linearity study was constructed from 0.1 to 70 μg/mL at λmax 205 nm. The limit of detection and limit of quantification were 0.025 and 0.082 μg/mL, respectively, and the relative standard deviation (RSD) % was 0.518%. Three spiked levels of concentration (20.0, 40.0, and 70.0 μg/mL) were used for the validation method. The percentage recovery for the three spiked samples was ranged between 98.743 and 99.432 and the RSD% was between 0.051 and 0.202%, the formulation studies of oxymatrine between 99.487 and 99.798, and the RSD% was ranged from 0.045 to 0.057%. The developed method can be used accurately and selectively for the determination of oxymatrine in environmental samples and in the formulation.

scholarly journals Assessment of Arsenic Levels in Water, Sediment, and Human Hair around Ie Seu’um Geothermal Manifestation Area, Aceh, Indonesia

Water ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2343
Author(s):  
Irnawati Irnawati ◽  
Rinaldi Idroes ◽  
Utari Zulfiani ◽  
Muslim Akmal ◽  
Eko Suhartono ◽  
...  
Keyword(s):  
River Water ◽  
Water Samples ◽  
Hot Springs ◽  
Limit Of Detection ◽  
Graphite Furnace ◽  
Hot Water ◽  
Sediment Samples ◽  
Hair Samples ◽  
Relative Standard ◽  
Manifestation Area

The concentration of arsenic in water, sediment, and resident hair in the Ie Seu’um geothermal manifestation area has been analyzed using the Atomic Graphite Furnace Atomic Absorption Spectrophotometry (GF-AAS) method. Sediment and hair samples were prepared by wet digestion using an acid solution. The measurement results were validated by linearity, Limit of Detection (LoD), Limit of Quantification (LoQ), Relative Standard Deviation (%RSD), and %Recovery. The validation test showed that this method is very linear, sensitive, accurate, and precise with a correlation coefficient of 0.9999, LoD of 0.009 μg/L, LoQ of 0.027 μg/L, recovery values of 89.117–101.027% for hair samples and 88.337–105.175% for sediment samples, and RSD of 1.067%. The sample test results showed that the hot springs contained the highest arsenic with levels of 166.73 ± 0.0081 μg/L (IS1). In comparison, the water samples with the lowest arsenic levels were in the rivers that had not been in direct contact with the hot water (IS2) flow, which is 0.80 ± 0.0036 μg/L. All the river water samples that had been in contact with hot water were boreholes, and the resident boreholes located around hot water streams/rivers contaminated with arsenic were above the threshold. Only the river water that had not been in contact with hot water, refill water, and borehole waters outside the hot water flow were detected to be below the threshold level. All the sediment samples showed arsenic contamination, with levels ranging from 2.56–6.86 mg/kg, and it was still within the normal limits recommended by the National Oceanic and Atmospheric Administration (NOAA). Arsenic exposures in communities living around the Ie Seu’um geothermal area, Mesjid Raya Sub-District, Aceh Besar District, Aceh Province, were very high, where 9 out of 10 respondents were positive for arsenic with levels ranging from 54.59–164.57 mg/kg, which was already above the threshold set by the researchers.

scholarly journals EXTRACTION AND DETERMINATION OF TEBUCONAZOLE IN ENVIRONMENTAL SAMPLES FROM THE CITY OF KERBALA, IRAQ AND IN ITS FORMULATION USING HIGH- PERFORMANCE LIQUID CHROMATOGRAPHY (HPLC)

2020 ◽  
Vol 17 (34) ◽  
pp. 1046-1054
Author(s):  
Ihsan Mahdi SHAHEED ◽  
Saadiyah Ahmed DHAHIR
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Water Samples ◽  
High Performance ◽  
Limit Of Detection ◽  
Limit Of Quantification ◽  
Chromatography Method ◽  
Percentage Recovery ◽  
Relative Standard

The triazole, tebuconazole pesticide, was determined in its formulation and also in the river water samples collected from different agriculture areas in the Iraqui city of Kerbala using developed high-performance liquid chromatography method(HPLC) with UV-visible detection, The mobile composition phase was a mixture of acetonitrile:methanol (50:50 v/v) and the column was C18 (250 cm x 4.6 mm,5μm). Also modified dispersive liquidliquid microextraction (DLLME), which is regarded as an ecological -friendly method, was used for the extraction of tebuconazole from water samples using acetonitrile and chloroform as solvents extraction and dispersive agent, respectively. Linearity to maintain the calibration curve was achieved from (0.1-70) μg.mL-1 with a limit of detection(0.053) μg.mL-1 and limit of quantification (0.174) μg.mL-1. Three spiked levels of concentration (1.0, 5.0, and 10) μg.mL-1 were used for the validation of the method. The relative standard deviation (RSD%) was (0.294- 0.813)%, and the percentage recovery was (100.001-100.005). The formulation studies for two different concentrations (10 and 40) μg.mL-1, which prepared from tebuconazole formulation (Raxil ODS2 2%), gave acceptable percentage recovery between (98.956-99.833). The developed method can be used accurately for the determination of tebuconazole in water samples and in the formulation of tebuconazole effectively.

scholarly journals Vortex-assisted liquid–liquid microextraction combined with spectrophotometry for the determination of trace nitrite in water samples

2017 ◽  
Vol 17 (5) ◽  
pp. 1225-1231 ◽  
Author(s):  
Yang Jiao ◽  
Jianping Yu ◽  
Yaling Yang
Keyword(s):  
Organic Solvent ◽  
Water Samples ◽  
Limit Of Detection ◽  
Environmental Water ◽  
Cationic Dye ◽  
Optimum Conditions ◽  
Relative Standard ◽  
Optimized Conditions ◽  
Liquid Microextraction

A vortex-assisted liquid–liquid microextraction (VALLME) method using isooctanol as extractant followed by spectrophotometry was developed for the extraction and determination of trace nitrite in water samples. The method is based on selective ion-pairing complex (I3− MG+) formation of triiodideanion I3− with cationic dye malachite green (MG) at pH 3.0, and its subsequent extraction in an organic solvent. The extracted organic solvent-rich phase is diluted with methanol, and its absorbance is measured against an analyte blank at 630 nm. The variables affecting VALLME efficiency were investigated, and a set of optimized conditions was obtained. Under the optimum conditions, the linear range of nitrite was from 1.0 to 100 ng mL−1. The relative standard deviations (n = 10) were 2.1–3.9% and the limit of detection was 0.5 ng mL−1 and was successfully applied to the determination of nitrite in environmental water.

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