Improved potentiometric response of solid-contact lanthanum (III) selective electrode

APTMS-BCAD modified magnetic iron oxide for magnetic solid-phase extraction of Cu(II) from aqueous solutions

Fe₃O₄@SiO₂-3-aminopropyltrimethoxysilane-1,8-bis (3-chloropropoxy) anthracene-9,10-dione was synthesized as a new, sustainable, and environmentally friendly adsorbent for magnetic solid-phase extraction of Cu(II) from aqueous solutions. The structure of the adsorbent was characterized by FTIR, XRD, SEM, EDX, and TEM analysis. Optimum conditions for Cu(II) adsorption were determined as adsorbent dose 0.04 g, pH 5.0, contact time 120 min, and beginning concentration of 30 mg/L in the adsorption process. The adsorption capacity for Cu(II) ions was 43.67 mg/g and the removal efficiency was 84.72 percent. The Langmuir isotherm and the pseudo-second-order model fit the experimental data better. Adsorption was a spontaneous and endothermic process based on the obtained thermodynamic properties such as ΔG°, ΔH°, and ΔS°. The results showed that the sorbent has good selectivity in the presence of competing ions. The method was determined to be accurate and effective using real water samples and CRM.

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Magnetic Fe₃O₄@SiO₂-3-aminopropyl-trimethoxysilane-1,8-bis(3-chloropro-poxy) anthracene-9,10-dione was synthesized as a new, sustainable, and environmentally friendly adsorbent for magnetic solid-phase extraction of Cu(II) from aqueous solutions.

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The results showed that the presence of competitor ions did not have a significant effect on the sorption of Cu(II) ion and the sorbent had good selectivity.

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Using real water samples and CRM, the method was found to be accurate and effective.

Magnetic solid-phase extraction based on multi-walled carbon nanotubes combined ferroferric oxide nanoparticles for the determination of five heavy metal ions in water samples by inductively coupled plasma mass spectrometry

An excellent magnetic multi-walled carbon nanotubes (MMWCNT) containing carboxyl material modified with ferroferric oxide (Fe₃O₄) nanoparticles was synthesized as the adsorbent for magnetic solid-phase extraction (MSPE) of five heavy metal ions (Pb²⁺, Cu²⁺, Co²⁺, Cd²⁺, Cr⁴⁺) in water samples followed by on-line inductively coupled plasma mass spectrometry (ICP-MS) detection. The characteristics of the adsorbent were analyzed using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and vibrating sample magnetometer (VSM). Some factors affecting extraction efficiency including pH of sample solution, the amount of adsorbent, extraction method and time, concentration and volume of desorption solvent, desorption time and evaluation of coexisting ions were optimized. Under the optimum conditions, good linearity (r ≥ 0.9951) was obtained within the range of 0.1-50.0 ng·mL^-1. The limits of detection (LODs) and limits of quantification (LOQs) were 4.0-25.0 ng·L^-1 and 15.0-80.0 ng·L^-1, respectively. And satisfactory recoveries of five heavy metal ions ranged from 81.11% to 105.53% were acquired, and the relative standard deviations (RSDs) were no more than 6.05%. The MMWCNT synthesized had strong adsorption force for the five investigated heavy metal ions, respectively. Hence, the proposed method was so suitable and sensitive that it can be applied to the determination of trace analysis of heavy metals in water samples.

Silica Magnetic Graphene Oxide Improves the Effects of Stem Cell-Conditioned Medium on Acute Liver Failure

OBJECTIVE

Acute liver failure (ALF) is usually associated with inflammation and oxidation of hepatocytes and has high mortality and resource costs. Although mesenchymal stem cell-conditioned medium (MSC-CM) has therapeutic effects similar to MSC transplant in treating liver failure, it may not increase survival. On the other hand, graphene-based nanostructures have been proven useful in biomedicine. In this study, we investigated whether silica magnetic graphene oxide (SMGO) improved the effects of MSC-CM in protecting hepatocytes and stimulating the regeneration of damaged liver cells.

MATERIALS AND METHODS

To provide a rat model of ALF, male rats were injected intraperitoneally with carbon tetrachloride (CCl₄). The rats were randomly divided into six groups, namely control, sham, CCl₄, MSC-CM, SMGO, and MSC-CM + SMGO. In the experimental groups, the rats received, depending on the group, 2 mL/kg body weight CCl₄ and either MSC-CM with 5 × 10⁶ MSCs or 300 μg/kg body weight SMGO or both. Symptoms of ALF appeared 4 days after the injection. All groups were compared and analyzed both histologically and biochemically 4 days after the injection.

RESULTS

The results indicated that the use of SMGO enhanced the effect of MSC-CM in reducing necrosis, inflammation, aspartate transaminase, alanine aminotransferase, and alkaline phosphatase in the CCl₄-induced liver failure of the rat model. Also, the expression of vascular endothelial growth factor and matrix metalloproteinase-9 (MMP-9) was significantly upregulated after treatment with SMGO.

CONCLUSION

SMGO improved the hepatoprotective effects of MSC-CM on acute liver damage, probably by suppressing necrosis, apoptosis, and inflammation of hepatocytes.

Air-Stable Black Phosphorus Devices for Ion Sensing

Black phosphorus (BP) is one of the most attractive graphene analogues, and its properties make it a promising nanomaterial for chemical sensing. However, mono- and few-layer BP flakes are reported to chemically degrade rapidly upon exposure to ambient conditions. Therefore, little is known about the performance and sensing mechanism of intrinsic BP, and chemical sensing of intrinsic BP with acceptable air stability remains only theoretically explored. Here, we experimentally demonstrated the first air-stable high-performance BP sensor using ionophore coating. Ionophore-encapsulated BP demonstrated significantly improved air stability. Its performance and sensing mechanism for trace ion detection were systematically investigated. The BP sensors were able to realize multiplex ion detection with superb selectivity, and sensitive to Pb(2+) down to 1 ppb. Additionally, the time constant for ion adsorption extracted was only 5 s. The detection limit and response rate of BP were both superior to those of graphene based sensors. Moreover, heavy metal ions can be effectively detected over a wide range of concentration with BP conductance change following the Langmuir isotherm for molecules adsorption on surface. The simplicity of this ionophore-encapsulate approach provides a route for achieving air-stable intrinsic black phosphorus sensors that may stimulate further fundamental research and potential applications.