Carbon nanoparticles were prepared by refluxing the combustion soot of natural gas in nitric acid. Transmission Electron Microscopy measurements showed that the resulting particles exhibited an ...average diameter of 4.8 ± 0.6 nm, and the crystalline lattices were consistent with graphitic carbons. 13C NMR and FTIR spectroscopic measurements further confirmed the presence of sp2 carbons in the form of aryl and carboxylic/carbonyl moieties. The resulting carbon nanoparticles were found to emit photoluminescence with a quantum yield of approximately 0.43%. Additionally, the emission band energy of the carbon nanoparticle was very similar to that of much smaller carbon nanoparticles obtained from candle soot, suggesting that the photoluminescence might arise from particle surface states, analogous to the behaviors of semiconductor quantum dots with an indirect bandgap. In electrochemical measurements, two pairs of well-defined voltammetric waves were observed, which might be ascribed to the peripheral functional moieties that were analogous to phenanthrenequinone derivatives. Interestingly, the carbon nanoparticles might also be exploited as nanoscale structural scaffolds for the deposition of nanostructures of varied transition metals, leading to the formation of metal−carbon functional nanocomposites.
We herein report a turn-on fluorescent probe based on excited state intramolecular proton transfer (ESIPT) mechanism and self-immolative linker for hydrogen sulfide detection. The new probe exhibits ...high sensitivity and selectivity over other biologically relevant anions. Moreover, we show the utility of the probe for the detection of hydrogen sulfide in living cells as well.
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•A new ratiometric probe for hydrogen sulfide was reported.•The probe shows high selectivity and sensitivity to hydrogen sulfide.•The mechanism is based on excited state intramolecular proton transfer (ESIPT) azide group reduction and self-immolative linker.•The probe was used for the detection of hydrogen sulfide in living cells.
Murexide functionalized halloysite nanotubes have been developed to separate and concentrate trace Pd(II) from aqueous samples. Parameters that affected the sorption and elution efficiency were ...studied in column mode, and the new adsorbent presented high selectivity and adsorption capacity for the solid phase extraction of trace Pd(II).
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► Murexide modified halloysite nanotubes as adsorbent has been reported originally. ► This adsorbent has a unique selectivity for Pd(II) at pH 1.0. ► This adsorbent had high adsorption capacity for Pd(II). ► The precision and accuracy of the method are satisfactory.
The originality on the high efficiency of murexide modified halloysite nanotubes as a new adsorbent of solid phase extraction has been reported to preconcentrate and separate Pd(II) in solution samples. The new adsorbent was confirmed by Fourier transformed infrared spectra, X-ray diffraction, scanning electron microscope, transmission electron microscope and N
2 adsorption–desorption isotherms. Effective preconcentration conditions of analyte were examined using column procedures prior to detection by inductively coupled plasma-optical emission spectrometry (ICP-OES). The effects of pH, the amount of adsorbent, the sample flow rate and volume, the elution condition and the interfering ions were optimized in detail. Under the optimized conditions, Pd(II) could be retained on the column at pH 1.0 and quantitatively eluted by 2.5
mL of 0.01
mol
L
−1 HCl–3% thiourea solution at a flow rate of 2.0
mL
min
−1. The analysis time was 5
min. An enrichment factor of 120 was accomplished. Common interfering ions did not interfere in both separation and determination. The maximum adsorption capacity of the adsorbent at optimum conditions was found to be 42.86
mg
g
−1 for Pd(II).
The detection limit (3
σ) of the method was 0.29
ng
mL
−1, and the relative standard deviation (RSD) was 3.1% (
n
=
11). The method was validated using certified reference material, and has been applied for the determination of trace Pd(II) in actual samples with satisfactory results.
A novel dual-ligand reagent (2Z)-
N,
N′-bis(2-aminoethylic)but-2-enediamide, was synthesized and applied to prepare metal ion-imprinted polymers (IIPs) materials by ionic imprinted technique for ...selective solid-phase extraction (SPE) of trace Cd(II) from aqueous solution. In the first step, Cd(II) formed coordination linkage with the two ethylenediamine groups of the synthetic monomer. Then the complex was copolymerized with pentaerythritol triacrylate (crosslinker) in the presence of 2,2′-azobisisobutyronitrile as initiator. Subsequently, the imprinted Cd(II) was completely removed by leaching the dried and powdered materials particles with 0.5
M HCl. The obtained IIPs particles exhibited excellent selectivity for target ion. The distribution ratio (
D) values of Cd(II)–IIPs for Cd(II) were greatly larger than that for Cu(II), Zn(II) and Hg(II). The relative selective factor (
α
r) values of Cd(II)/Cu(II), Cd(II)/Zn(II) and Cd(II)/Hg(II) were 25.5, 35.3 and 62.1. The maximum static adsorption capacity of the ion-imprinted and non-imprinted sorbent for Cd(II) was 32.56 and 6.30
mg
g
−1, respectively. Moreover, the times of adsorption equilibration and complete desorption were remarkably short. The prepared Cd(II)–IIPs were shown to be promising for solid-phase extraction coupled with inductively coupled plasma atomic emission spectrometry (ICP-AES) for the determination of trace Cd(II) in real samples. The precision (R.S.D.) and detection limit (3
σ) of the method were 2.4% and 0.14
μg
L
−1, respectively. The column packed with Cd(II)–IIPs was good enough for Cd(II) separation in matrixes containing components with similar chemical behaviour such as Cu(II), Zn(II) and Hg(II).
A new method that utilizes ethylenediamine-modified multiwalled carbon nanotubes as a solid-phase extractant has been developed for simultaneous preconcentration of trace Cr(III), Fe(III) and Pb(II) ...prior to the measurement by inductively coupled plasma optical emission spectrometry. Identification of the surface modification was characterized and performed on the basis of transmission electron microscopy, Fourier transform infrared spectra and elemental analysis. The separation/preconcentration conditions of analytes were investigated, including the pH value, the shaking time, the sample flow rate and volume, the elution condition and the interfering ions. The maximum adsorption capacity of the adsorbent at optimum conditions was found to be 39.58, 28.69 and 54.48
mg
g
−1 for Cr(III), Fe(III) and Pb(II), respectively. The detection limits of the method were under 0.35
ng
mL
−1 and the relative standard deviations were lower than 3.5% (
n
=
11). The method was validated using a certified reference material, and has been applied for the determination of trace Cr(III), Fe(III) and Pb(II) in biological and natural water samples with satisfactory results.
A new Ni(II)-imprinted amino-functionalized silica gel sorbent with excellent selectivity for nickel(II) was prepared by an easy one-step reaction by combining a surface imprinting technique for ...selective solid-phase extraction (SPE) of trace Ni(II) in water samples prior to its determination by inductively coupled plasma atomic emission spectrometry (ICP-AES). Compared with non-imprinted polymer particles, the ion-imprinted polymers (IIPs) had higher selectivity and adsorption capacity for Ni(II). The maximum static adsorption capacity of the ion-imprinted and non-imprinted sorbent for Ni(II) was 12.61 and 4.25
mg
g
−1, respectively. The relatively selective factor (
α
r) values of Ni(II)/Cu(II), Ni(II)/Co(II), Ni(II)/Zn(II) and Ni(II)/Pd(II) were 45.99, 32.83, 43.79 and 28.36, which were greater than 1. The distribution ratio (
D) values of Ni(II)-imprinted polymers for Ni(II) were greatly larger than that for Cu(II), Co(II), Zn(II) and Pd(II). The detection limit (3
σ) was 0.16
ng
mL
−1. The relative standard deviation of the method was 1.48% for eight replicate determinations. The method was validated by analyzing two certified reference materials (GBW 08618 and GBW 08402), the results obtained is in good agreement with standard values. The developed method was also successfully applied to the determination of trace nickel in plants and water samples with satisfactory results.
In this work, a new 2-(2-oxoethyl)hydrazine carbothioamide modified silica gel (SG-OHC) sorbent was prepared and applied for preconcentration of trace mercury(II) prior to the measurement by ...inductively coupled plasma atomic emission spectrometry (ICP-AES). The optimization of some analytical parameters affecting the adsorption of the analyte such as acidity, shaking time, sample flow rate and volume, eluent condition, and interfering substances were investigated. At pH 3, the maximum static adsorption capacity of Hg(II) onto the SG-OHC was 37.5
mg
g
−1. The quantitative recovery (>95%) of Hg(II) could be obtained using 2
mL of 0.5
mol
L
−1
HCl and 1% CS(NH
2)
2 solution as eluent. Common coexisting substances did not interfere with the separation of mercury(II) under optimal conditions. The detection limit of present method was 0.10
ng
mL
−1, and the relative standard deviation (RSD) was lower than 4.0% (
n
=
8). The prepared sorbent was successfully applied for the preconcentration of trace Hg(II) in certified and water samples with satisfactory results.
▶ A new method was established for the preconcentration of Cr(III), Hg(II) and Pb(II). ▶ Cr(III), Hg(II) and Pb(II) binding only need 2min. ▶ High adsorption capacity for Cr(III), Hg(II) and Pb(II). ...▶ The precision and accuracy of the method are satisfactory.
In this work, the immobilization of 4-aminoantipyrine onto bentonite was carried out and it was then used to investigate the adsorption behavior of Cr(III), Hg(II) and Pb(II) ions from aqueous solutions. The separation and preconcentration conditions of analytes were investigated, including effects of pH, the shaking time, the sample flow rate and volume, the elution condition and the interfering ions. Under optimum pH value (pH 4.0), the maximum static adsorption capacity of the sorbent was found to be 38.8, 52.9 and 55.5mgg−1 for Cr(III), Hg(II) and Pb(II), respectively. 2.0mL of 2% thiourea in 1.0M HCl solution effectively eluted the adsorbed metal ions. The detection limit (3σ) of this method defined by IUPAC was found to be 0.12, 0.09 and 0.23ngmL−1 for Cr(III), Hg(II) and Pb(II), respectively. The relative standard deviation (RSD) was lower 3.0% (n=8). The developed method has been validated by analyzing certified reference materials and successfully applied to the determination of trace Cr(III), Hg(II) and Pb(II) in water samples with satisfactory results.
A procedure for separation and preconcentration trace amount of Cu(II), Fe(III) and Pb(II) by 2-((2-aminoethylamino)methyl)phenol-functionalized activated carbon (AC-AMP) packed column has been ...proposed. Under the optimized conditions (pH 4, flow rate 2.0
mL
min
−1), Cu(II), Fe(III) and Pb(II) were retained on the column, then quantitatively eluted by 2
mL 1
mol
L
−1 nitric acid solution and determined by inductively coupled plasma-optical emission spectrometry (ICP-OES). The tolerance limits of electrolytes were very high. The adsorption capacity of AC-AMP was found to be 12.1, 67.1, and 16.2
mg
g
−1 for Cu(II), Fe(III), and Pb(II), respectively. According to the definition of International Union of Pure and Applied Chemistry, the detection limits (3
σ) of this method for Cu(II), Fe(III) and Pb(II) were 0.27, 0.41 and 0.16
μg
L
−1, respectively. The relative standard deviation under optimum conditions is less than 3.0% (
n
=
11). The proposed method has been validated by analyzing a certified reference material and successfully applied to the preconcentration and determination of Cu(II), Fe(III), and Pb(II) in actual samples with satisfactory results.
A new method that utilizes ethylenediamine-modified activated carbon (AC-EDA) as a solid-phase extractant has been developed for simultaneous preconcentration of trace Cr(III), Fe(III), Hg(II) and ...Pb(II) prior to the measurement by inductively coupled plasma optical emission spectrometry (ICP-OES). The new sorbent was prepared by oxidative surface modification. Experimental conditions for effective adsorption of trace levels of Cr(III), Fe(III), Hg(II) and Pb(II) were optimized with respect to different experimental parameters using batch and column procedures in detail. The optimum pH value for the separation of metal ions simultaneously on the new sorbent was 4.0. Complete elution of absorbed metal ions from the sorbent surface was carried out using 3.0
mL of 2% (%w/w) thiourea and 0.5
mol
L
−1 HCl solution. Common coexisting ions did not interfere with the separation and determination of target metal ions. The maximum static adsorption capacity of the sorbent at optimum conditions was found to be 39.4, 28.9, 60.5 and 49.9
mg
g
−1 for Cr(III), Fe(III), Hg(II) and Pb(II), respectively. The time for 94% adsorption of target metal ions was less than 2
min. The detection limits of the method was found to be 0.28, 0.22, 0.09 and 0.17
ng
mL
−1 for Cr(III), Fe(III), Hg(II) and Pb(II), respectively. The precision (R.S.D.) of the method was lower 4.0% (
n
=
8). The prepared sorbent as solid-phase extractant was successfully applied for the preconcentration of trace Cr(III), Fe(III), Hg(II) and Pb(II) in natural and certified samples with satisfactory results.
