Determination Of Cd Research Articles

The ethylene response factor gene, ThDRE1A, is involved in abscisic acid- and ethylene-mediated cadmium accumulation in Tamarix hispida

Tamarix hispida is highly tolerant to salt, drought and heavy metal stress and is a potential material for the remediation of cadmium (Cd)-contaminated soil under harsh conditions. In this study, T. hispida growth and chlorophyll content decreased, whereas flavonoid and carotenoid contents increased under long-term Cd stress (25 d). The aboveground components of T. hispida were collected for RNA-seq to investigate the mechanism of Cd accumulation. GO and KEGG enrichment analyses revealed that the differentially expressed genes (DEGs) were significantly enriched in plant hormone-related pathways. Exogenous hormone treatment and determination of Cd2+ levels showed that ethylene (ETH) and abscisic acid (ABA) antagonists regulate Cd accumulation in T. hispida. Twenty-five transcription factors were identified as upstream regulators of hormone-related pathways. ThDRE1A, which was previously identified as an important regulatory factor, was selected for further analysis. The results indicated that ThABAH2.5 and ThACCO3.1 were direct target genes of ThDRE1A. The determination of Cd2+, ABA, and ETH levels indicated that ThDRE1A plays an important role in Cd accumulation through the antagonistic regulation of ABA and ETH. In conclusion, these results reveal the molecular mechanism underlying Cd accumulation in plants and identify candidate genes for further research.

Cu-doped graphitic carbon nitride composite functionalized sensor for sensitive Cd2+ detection

Cadmium ions (Cd2+) are one of the highly poisonous heavy metal ions in the environment, but at present, the detection of Cd2+ on the market has the disadvantages of complex operation, high detection cost and slow detection speed, so it is urgent to develop rapid and sensitive detection platforms for detecting Cd2+. In this study, a novel electrochemical sensor (g-C3N4/CuNps) was successfully fabricated. g-C3N4/CuNps composite has a large and unique surface area that is beneficial to the adsorption and preconcentration of Cd2+. The experiment parameters such as deposition potential, deposition time, pH of supporting electrolyte, supporting electrolyte, the amount of g-C3N4/CuNps being coated on the GCE, were optimized. Under the optimized conditions, the electrochemical performances of g-C3N4/CuNps composites modified sensor have been investigated, which shows excellent wider linear range and lower detection limit (0.098 nM). The linear ranges of Cd2+ detections were 1-100µgL-1. Moreover, the sensor shows desirable stability, selectivity, and reproducibility for detecting Cd2+. For real water samples, the sensor has a satisfactory recovery rate, indicating that the sensor could be successfully applied in the determination of Cd2+ in environmental water. Therefore, the designed sensor provides a potential simple and low cost material for electrochemical detection of Cd2+.

Amide-decorated carbon dots as sensitive and selective probes for fluorescence enhancement detection of cadmium ion

As highly toxic metal ions, cadmium ions (Cd2+) are prevalent in varying concentrations around the world. The establishment of an accurate and effective method for Cd2+ determination with high sensitivity and selectivity is of particular concern. The present work fabricated a fluorescence chemosensor for the detection of Cd2+ based on functionalized carbon dots (CDs), which were hydrothermally prepared using amidated hyperbranched-polyethyleneimine (HPEI). As investigated by FTIR, NMR, and XPS, the stably grafted amide groups endowed the CDs with thermosensitivity and high cloud point due to the change in hydrophilic-hydrophobic behaviors. The CDs chemosensor with optimal amidation degree exhibited high sensitivity, selectivity, and stability in the determination of Cd2+ from various water environments. Notably, the fluorescence intensity enhanced with the increase of Cd2+ concentration, originating from the improved structure rigidity caused by the interactions between grafted amides and Cd2+. These impressive features made the CDs not only sensitive to detecting Cd2+ in low-concentration solutions with a limit of detection of 3.41 nM (the lowest known value for Cd2+ detection) but also accurate for the quantification in high-concentration solutions with a detectable Cd2+ concentration of 6.0 × 10−2 M. Owing to the broad detection range, the CDs developed in present work show great potential applications in various scenarios.

Determination of Cd2+ and Pb2+ by polyindole/Mn2O3 nanocomposite and polyindole/Mn2O3/polyaniline nanofibers modified glassy carbon electrode

Determination of Cd2+ and Pb2+ by polyindole/Mn2O3 nanocomposite and polyindole/Mn2O3/polyaniline nanofibers modified glassy carbon electrode

Speciation and Enrichment of Cadmium and Lead from Water Samples using Fe3O4/rGO Sorbent in Dispersive Magnetic Micro-Solid Phase Extraction with Inductively Coupled Plasma-Optical Emission Spectroscopy

This work reports the development of dispersive magnetic solid-phase extraction (DMSPE) with high resolution ICP-OES for the pre-concentration of cadmium and lead in water samples. The method uses magnetic reduced graphene oxide (Fe3O4/rGO) as adsorbent. The influences of sample pH, extraction time, desorption solvent and desorption time were evaluated and optimized. In the optimized conditions, linear calibration curves for Cd2+ and Pb2+ were obtained in the range of 10-2000 μg L-1 with correlation coefficients of 0.9996 and 0.9995, respectively. Low detection limits of Cd2+ and Pb2+ were found to be 9.03 μg L-1 and 12.4 μg L-1, respectively. Good relative recovery values, in the range of 91-95% and excellent repeatability of 6.4-9.9%, (n = 3) were obtained. The results revealed that Fe3O4/rGO can be a suitable nanocomposite sorbent in the speciation and pre-concentration of Cd2+ and Pb2+ for tap water and drinking water samples. The method is rapid, selective, reliable and environmentally friendly for the determination of Cd2+ and Pb2+ in water samples.

Determination of Cd2+, Cu2+, Mn2+, Pb2+, and Zn2+ in Aqueous Solution after Their Separation and Preconcentation as Metal - Dithizone Complexes on Activated Carbon

A simple and sensitive method for preconcentration and determination of Cd2+, Cu2+, Mn2+, Pb2+ and Zn2+ by flame atomic absorption spectrophotometer was developed. The method is based on the sorption of the studied elements as metal-dithizone complexes (M-DZ) on activated carbon (AC). The effect of various parameters (pH, shaking time, AC amount, ligand concentrations, eluent concentration, and solution volume) on quantitative sorption of metal-dithizone chelates using AC was investigated. The studied elements were eluted from AC simply with HNO3 acid. The results revealed that the optimum pH values for the sorption were 4 for Cu2+, 6 for Zn2+, 8 for Pb2+ and 10 for Cd2+ and Mn2+; shaking time was 10 min for Mn2+ and Pb2+, 30 min for Cu2+ and Zn2+ and 50 min for Cd2+; AC amount was 0.2 g for Zn2+, 0.3 g for Cd2+, 0.5 g for Pb2+, 0.6 g for Mn2+ and 0.8 g for Cu2+; metal: ligand ratio was found to be (1:2 ratio), and eluent concentration used was 1 mol L-1 for Cd2+ and Mn2+, 2 mol L-1 for Zn2+ and 4 mol L-1 for Cu2+ and Pb2+. The method can be applied with a preconcentration factor of 20 for Cd2+, and 40 for Cu2+, Mn2+, Pb2+, and Zn2+. Preconcentration from various water samples showed recovery in the range 95-108 %, confirming the effectiveness and precision of the solid-phase method developed using activated carbon for enrichment of metals examined.

Activated Hordeum vulgare L. dust as carbon paste electrode modifier for the sensitive electrochemical detection of Cd2+, Pb2+ and Hg2+ions

ABSTRACT Hordeum vulgare L. dust (HVW) chemically activated using Na2CO3 (HVW-Na2CO3) was characterised by several techniques (SEM, FTIR and TGA/DTG). The increase in the surface charge of the biomaterial induced by the activation process was demonstrated by multisweep cyclic voltammetry. The modified HVM was then exploited as carbon paste electrode (HVW-Na2CO3/CPE) modifier to prepare a sensor which was applied in the determination of Cd2+, Pb2+ and Hg2+at trace level by stripping voltammetry. Key experimental variables (nature of stripping medium, modifier mass in CPE, electrolysis time and potential and pH of preconcentration solution) were optimised to detect Cd2+, Pb2+ and Hg2+ at HVW-Na2CO3/CPE. Under optimised conditions, calibration plots were obtained for all analytes. The low limits of detection (3s/m) were found to be 1.82 nM, 0.0691 nM and 0.237 nM for Cd2+, Pb2+and Hg2+respectively. The sensor was successfully applied to the detection of trace metals in real samples.

A dispersive liquid–liquid microextraction based on a task-specific ionic liquid for enrichment of trace quantity of cadmium in water and food samples

In this work, a hydrophilic task-specific ionic liquid (TSIL) of 1-chloroethyl-3-methylimidazolium chloride functionalized with 8-hydroxyquinoline was used in a dispersive liquid–liquid microextraction method followed by flame atomic absorption spectrometry for the enrichment and determination of trace amounts of cadmium (Cd2+) ions. The simultaneous chelation and extraction of Cd2+ ions was carried out by the TSIL. Fine droplets of the water-immiscible TSIL containing target analyte were generated in situ by addition of an anion exchanger potassium hexafluorophosphate (KPF6) salt to the sample tube. After phase separation by centrifugation for 4 min, the sedimented TSIL was diluted with acidified ethanol for measurement of Cd2+ content. Some significant parameters influence the preconcentration of Cd2+ ions such as sample pH, TSIL volume, amount of KPF6, non-ionic surfactant and salt concentration were investigated. Under the optimal conditions, calibration curve was linear in the range of 5–250 µg L−1 Cd2+ with correlation coefficient of 0.9975 and a detection limit of 0.55 µg L−1. The relative standard deviation for six replicate measurements of 50 µg L−1 Cd2+ was 1.5%. The method was successfully applied for the extraction and determination of Cd2+ ions in water and food samples.

Development of carbon paste electrode modified with cadmium ion-imprinted polymer for selective voltammetric determination of Cd2+

ABSTRACTA simple and fast voltammetric method based on a new electrode composed of carbon paste electrode/bifunctional hybrid ion imprinted polymer (CPE/IIP) was developed for the quantification of Cd2+ in water samples. The voltammetric measurements by Differential Pulse Voltammetry were performed by using CPE containing 11.0 mg of IIP under phosphate buffer solution at concentration 0.1 mol L−1 and pH 6.5. The electrochemical method was carried out by Cd2+ preconcentration at −1.2 V during 210 s, followed by anodic stripping. The performance of IIP towards Cd2+ determination was evaluated by comparison to non-imprinted polymer, whose detectability of IIP was much higher (45%). The sensitivity of the sensor was found to be 0.0105 µA/µg L−1. The limits of detection and limits of quantification were found to be 4.95 μg L−1 and 16.4 μg L−1, respectively. The developed method was successfully applied to Cd2+ determination in mineral, tap and lake water samples, whose results are in agreement with thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) used as reference analytical technique. According to achieved results, the developed method can be used for routine analysis of quality control of water samples from different sources.

Determination of Cd2+, Cr3+, Cu2+ and Zn2+ in Traditional Chinese Medicine Shuanghuanglian Oral Liquid by High Performance Capillary Electrophoresis

Determination of Cd2+, Cr3+, Cu2+ and Zn2+ in Traditional Chinese Medicine Shuanghuanglian Oral Liquid by High Performance Capillary Electrophoresis

Cadmium determination based on silver nanoparticles modified with 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane

We propose a simple, fast and sensitive colorimetric method for the determination of Cd2+ using 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane modified silver nanoparticles. The addition of Cd2+ causes the aggregation of AgNPs, while other ions do not have such effect. As a result, the color of the solution changes from yellow to red which can be detected using naked eye or by UV–Vis spectroscopy. The aggregation of the AgNPs is confirmed by UV–Vis and transmission electron microscopy. Limit of detection is found to be 0.016 µM for Cd2+ ions. A linear calibration plot is correlated to the concentration of cadmium ion in the 0.5–6.0 μM range with the naked-eye detection limit of 2.0 µM. The method was successfully applied to determine Cd2+ in water and urine samples and gave recoveries that ranged from 93.3 to 98.6%.

A Flow System for Detection of Cadmium Based on 3D-Printed Thin-Layer Cell and Flow-field Shaped Electrode

Abstract The concept of flow-field shaped (FFS) electrode was introduced for the first time and a FFS based three-electrodes system was built accordingly. Combined with a 3D-printed thin-layer flow cell (TLFC), a flow electrochemical system for detection of Cd2+ using square wave stripping voltammetry (SWSV) was thus constructed. Several factors that might affect the determination of Cd2+ were investigated, including the shape of the FFS electrode, the method of measurements, the buffer medium, the flow rate, and the deposition time. The results suggested this new detection system offered high sensitivity, good reproducibility, and great stability. Under the optimized conditions, the system showed a good linearity for detecting Cd2+ in the range of 2–100 μg L−1 with a correlation coefficient of 0.997, and a detection limit of 0.5 μg L−1 was achieved. Furthermore, the newly designed system was used to determine trace Cd2+ in environmental water samples and fermentation broths of biological methane. The results were consistent with that obtained with ICP-AES analysis and the recovery rates were found to be 90%–106%.

Determination of Cd2+ and Pb2+ Based on Mesoporous Carbon Nitride/Self-Doped Polyaniline Nanofibers and Square Wave Anodic Stripping Voltammetry.

The fabrication and evaluation of a glassy carbon electrode (GCE) modified with self-doped polyaniline nanofibers (SPAN)/mesoporous carbon nitride (MCN) and bismuth for simultaneous determination of trace Cd2+ and Pb2+ by square wave anodic stripping voltammetry (SWASV) are presented here. The morphology properties of SPAN and MCN were characterized by transmission electron microscopy (TEM), and the electrochemical properties of the fabricated electrode were characterized by cyclic voltammetry (CV). Experimental parameters, such as deposition time, pulse potential, step potential, bismuth concentration and NaCl concentration, were optimized. Under the optimum conditions, the fabricated electrode exhibited linear calibration curves ranging from 5 to 80 nM for Cd2+ and Pb2+. The limits of detection (LOD) were 0.7 nM for Cd2+ and 0.2 nM for Pb2+ (S/N = 3). Additionally, the repeatability, reproducibility, anti-interference ability and application were also investigated, and the proposed electrode exhibited excellent performance. The proposed method could be extended for other heavy metal determination.

Electrochemical determination of Cd2+ at a titanium electrode modified with a lead film by square wave anodic stripping voltammetry

The modified titanium electrode with lead film (PbTiE) was used for determination of trace levels of cadmium using square wave anodic stripping voltammetry (SWASV). The measurement of cadmium on the PbTiE has the best reply under the following conditions of PbTiE preparation: 10–3 mol L–1 Pb2+ in HCl (pH 1.0), deposition potential of–1.40 V vs. Ag/AgCl/KClsat and deposition time of 300 s. The PbTiE reveals highly linear behavior in the concentration range 5 × 10–8 to 10–6 mol L–1, with a limit of detection of 2 × 10–9 mol L–1. Interference of nine ionic species was evaluated. The measurements were carried out without removing dissolved oxygen from the solution.

Individual and Simultaneous Stripping Voltammetric and Mutual Interference Analysis of Cd2+, Pb2+ and Hg2+ with Reduced Graphene Oxide-Fe3O4 Nanocomposites

This study attempts to understand the stripping behaviors and mutual impact of different metal ions in electrochemical detection. A reduced graphene oxide-Fe3O4 (rGO-Fe3O4) nanocomposites with small-sized Fe3O4 is prepared by a simple and one-pot synthesis method. The morphology and structure of the nanocomposites are investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectrometer and X-ray diffraction. The electrochemical behaviors of nanocomposite electrode are characterized by cyclic voltammetry and electrochemical impedance spectroscopy. The individual and simultaneous stripping analysis of Cd2+, Pb2+ and Hg2+ using rGO-Fe3O4 electrode are performed by square wave anodic stripping voltammetry (SWASV) under optimized condition, and experimental data show that there are differences in some parameters such as sensitivities and detection limits, etc. To further understand phenomena, a series of interference tests are systematically evaluated by SWASV in detail. The experimental results demonstrate that determination of Cd2+ is easy to be influenced by Pb2+ and Hg2+. At last, the proposed electrode is used to analyze content of Pb2+ in soil sample. The result obtained at the nanocomposite electrode is comparable to that obtained by inductively coupled plasma atomic emission spectroscopy, indicating a good accuracy. The sensor could provide an effective detection and analysis method for heavy metal ions.

Determination of Cd2+ by ultrasound-assisted square wave anodic stripping voltammetry with a boron-doped diamond electrode

In this paper, a boron-doped diamond film, a new type of environmentally friendly electrode, was used as the sensing electrode. The analysis of trace metal cadmium was carried out by ultrasound-assisted square wave anodic stripping voltammetry. The influence of some experimental variables such as the supporting electrolyte, accumulation potential and accumulation time were investigated. Under the optimized conditions, the stripping peak currents showed a good linear relationship with the Cd2+ concentration ranging from 19.80 to 243.9 μg L−1 with a detection limit of 1.0 μg L−1. The effects of potential interfering ions were also studied, and the method was successfully applied to the determination of Cd2+ in real-water samples.

Optimized solid phase extraction based on diethyldithiocarbamate-coated Fe3O4 magnetic nanoparticles followed by ICP-OES for determination of Cd(II) and Ni(II) in rice and water samples

In the present study, application of Fe3O4 magnetic nanoparticles (MNPs) coated with diethyldithiocarbamate as a solid-phase sorbent for extraction of trace amounts of cadmium (Cd2+) and nickel (Ni2+) ions by the aid of ultrasound was investigated. The analytes were determined by inductively coupled plasma-optical emission spectroscopy. Fe3O4 MNPs were prepared by solvothermal method and characterized with dynamic light scattering, scanning electron microscope and X-ray diffraction. Response surface methodology was used for optimization of the extraction process and modeling the data. The optimal conditions obtained were as follows: chelating agent, 1.2 g L−1; pH, 6.13; sonication time, 13 min and Fe3O4 MNPs, 10.3 mg. The calibration curves were linear over the concentration range of 1–1,000 μg L−1 for Cd2+ and 2.5–1,000 for Ni2+ with the determination coefficients (R 2) of 0.9997 and 0.9995, respectively. The limits of detection were 0.27 μg L−1 for Cd2+ and 0.76 μg L−1 for Ni2+. The relative standard deviations (n = 7, C = 200 μg L−1) for determination of Cd2+ and Ni2+ were 2.0 and 2.7 %, respectively. The relative recoveries of the analytes from tap, river and lagoon waters and rice samples at the spiking level of 10 μg L−1 were obtained in the range of 95–105 %.

Electrochemical determination of cadmium and lead based on the joint enhancement effects of SBA-16 and iodide

Mesoporous SBA-16 was synthesized using tetraethoxysilane as silicon source and a ternary system consisting of surfactant F127, water and butanol. Owing to the excellent properties of SBA-16 such as lager surface area and strong accumulation ability, the stripping peak current of Cd2+ and Pb2+ remarkably increases at the SBA-16 modified carbon paste electrode. Moreover, the peak current of Cd2+ and Pb2+ further enhances after the addition of I−. Under the joint enhancement effects of SBA-16 and I−, the detection sensitivity of Cd2+ and Pb2+ is greatly improved. The influences of concentration of I−, amount of SBA-16, accumulation potential and time were investigated. As a result, a new electrochemical method with high sensitivity was developed for the simultaneous determination of Cd2+ and Pb2+. The limit of detection is 0.6 nM for Cd2+ and 1 nM for Pb2+. It was used to determine Cd2+ and Pb2+ in waste water sample, and the results consisted with the values that obtained by atomic absorption spectrometry.

Sensitive Simultaneously Determination of Cd<sup>2+</sup> and Pb<sup>2+</sup> by Polypyrrole/Multi-Walled Carbon Nanotube Modified Electrode

A new functionalized composites (PPy/c-MWNT) by carboxylic multiwalled carbon nanotube (c-MWNT) with polypyrrole (PPy) was studied. PPy/c-MWNT modified glassy carbon electrode (PPy/c-MWNT/GCE) for determination of Cd2+ and Pb2+ was described by cyclic voltammetry, electrochemical impedance spectroscopy, and anodic stripping voltammetry (ASV). PPy/c-MWNT/GCE greatly improved the sensitivity of determining Cd2+ and Pb2+. The striping peak currents changed linearly with the concentration of Cd2+ from 1.0×10-4 to 2.0×10-7 mol/L for an accumulation time of 400 s, and Pb2+ from 1.0×10-4 to 1.0×10-7 mol/L. The high sensitivity, selectivity, and stability of the PPy/c-MWNT/GCE demonstrated its practical application for a simple, rapid and economical determination of trace level of Cd2+ and Pb2+ in water samples

Pleurotus eryngii immobilized Amberlite XAD-16 as a solid-phase biosorbent for preconcentrations of Cd2+ and Co2+ and their determination by ICP-OES

This article reports a method that is used for the preconcentration and determination of Cd2+ and Co2+ in vegetables, using Pleurotus eryngii immobilized Amberlite XAD-16 as a solid-phase biosorbent. The concentrations of metals were determined by inductively coupled plasma-optical spectrometry (ICP-OES). Critical parameters, such as the pH of the solution, flow rate, the amount of biosorbent, type and volume of eluent, and the sample volume, that affect the solid-phase extraction (SPE) procedure were optimized. The optimum extraction conditions were determined as being a pH of 6.0 for Cd2+ and of 5.0 for Co2+; a sample flow rate of 2.0mLmin−1; 200.0mg of biosorbent; and 5.0mL of 1.0molL−1 HCl as eluent. The capacities of the biosorbent for metal uptake were found to be 11.3 and 9.8mgg−1 for Cd2+ and Co2+ ions, respectively. Limit of quantitations (LOQs) were found to be 0.67 and 0.82ngmL−1, respectively, for Cd2+ and Co2+. The linear working curves were observed to be in the linear range from 1.0 to 50.0ngmL−1, and possessed high correlation coefficients. The use of the SPE method showed 50.7- and 35.7-fold improvements in the sensitivities of ICP-OES. The developed method was successfully applied to NCS ZC-73014 (a certified reference tea sample). Relative standard deviations (RSD) were lower than 5.0%. The Cd2+ and Co2+ concentrations in the different parts (leave, root, stem, and fruit) of purslane, onion, rocket, okra, and aubergine were determined after microwave digestion and solid-phase extraction by P. eryngii immobilized on Amberlite XAD-16.