The determination of methylmercury in biological samples by HPLC coupled to ICP-MS detection

Plasmonic Nano Silver: An Efficient Colorimetric Sensor for the Selective Detection of Hg2+ Ions in Real Samples

Environmental pollution caused by heavy metal ions has become a major health problem across the world. In this study, a selective colorimetric sensor based on starch functionalized silver nanoparticles (St-Ag NPs) for rapid detection of Hg2+ in real samples was developed. The environmentally friendly green approach was utilized to synthesize starch functionalized silver nanoparticles (St-AgNPs). A multi-technique approach involving UV-Vis absorption spectroscopy, Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and scanning electron microscope (SEM) was used for the characterization of St-Ag NPs. These starch functionalized AgNPs were tested for the detection of heavy metals at 25 °C. The screening process revealed clear changes in the AgNPs color and absorption intensity only in the presence of Hg2+ due to the redox reaction between Ag0 and Hg2+. The color and absorption intensity of nanoparticles remain unchanged in the presence of all the other tested metals ion. The proposed method has strong selectivity and sensitivity to Hg2+ ions, with a detection limit of 1 ppm revealed by UV-visible spectrophotometry. The proposed procedure was found to be successful for the detection of Hg2+ in real samples of tap water.

In vivo study of dose-dependent antioxidant efficacy of functionalized core-shell yttrium oxide nanoparticles

Abstract

Herein, we assess the dose-dependent antioxidant efficacy of ultrafine spherical functionalized core–shell yttrium oxide nanoparticles (YNPs) with a mean size of 7–8 nm and modified with poly EGMP (ethylene glycol methacrylate phosphate) and N-Fluorescein Acrylamide. The antioxidant properties of these nanoparticles were investigated in three groups of Sprague–Dawley rats (10 per group) exposed to environmental stress daily for 1 week and one control group. Groups 2 and 3 were intravenously injected twice a week with YNPs at 0.3 and 0.5 mg at 2nd and 5th day of environmental stress exposure respectively. Different samples of blood and serum were collected from all experimental groups at end of the experiment to measure oxidative biomarkers such as total antioxidant capacity (TAC), hydroxyl radical antioxidant capacity (HORAC), oxygen radical antioxidant capacity (ORAC), malondialdehyde (MDA), and oxidants concentration as hydrogen peroxide (H₂O₂). The liver, brain, and spleen tissues were collected for fluorescence imaging and histopathological examination in addition to brain tissue examination by transmission electron microscope (TEM). Inductively coupled plasma-mass spectrometry (ICP-MS) was used to estimate YNPs translocation and concentration in tissues which is consecutively dependent on the dose of administration. Depending on all results, poly EGMP YNPs (poly EGMP yttrium oxide nanoparticles) can act as a potent direct antioxidant in a dose-dependent manner with good permeability through blood–brain barrier (BBB). Also, the neuroprotective effect of YNPs opening the door to a new therapeutic approach for modulating oxidative stress–related neural disorders.

Highlights

• The dose-dependent antioxidant efficacy of ultrafine spherical functionalized core–shell yttrium oxide nanoparticles (YNPs) with a mean size of 7–8 nm and modified with poly EGMP (ethylene glycol methacrylate phosphate) and N-Fluorescein Acrylamide was assessed.

• The dose of administration directly affecting the brain, liver, and spleen tissues distribution, retention, and uptake of YNPs and direct correlation between the absorbed amount and higher dose administered.

• YNPs can act as a potent direct antioxidant in a dose-dependent manner with good permeability through blood–brain barrier (BBB).

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s00210-022-02219-1.

Determination of metal uptake in single organisms, Corophium volutator, via complementary electrothermal vaporization/inductively coupled plasma mass spectrometry and laser ablation/inductively coupled plasma mass spectrometry

RATIONALE

(Eco-)toxicological effects are mostly derived empirically and are not correlated with metal uptake. Furthermore, if the metal content is determined, mostly bulk analysis of the whole organism population is conducted; thus, biological variability is completely disregarded, and this may lead to misleading results. To overcome this issue, we compared two different solid sampling techniques for the analysis of single organisms.

METHODS

In this study, complementary electrothermal vaporization/inductively coupled plasma mass spectrometry (ETV/ICP-MS) ⇔ laser ablation/inductively coupled plasma mass spectrometry (LA/ICP-MS)-based methods for the analysis of individual organisms were developed and the results obtained were compared with the concentrations obtained after digestion and measured using ICP-MS. For this purpose, a common (eco-)toxicological test organism, the mud shrimp Corophium volutator, was selected. As proof-of-concept application, these organisms were incubated with environmentally relevant metals from galvanic anodes, which are often used for protection against metal corrosion in, for example, offshore wind farms.

RESULTS

The bulk analysis revealed that large quantities of the incubated elements were detectable. Using the ETV/ICP-MS method, we could identify a high biovariability within the population of organisms tested. Using the LA/ICP-MS method, it could be determined that the large quantities of the elements detected were due to adsorption of the metals and not due to uptake, which correlates well with the absence of (eco-)toxicological effects.

CONCLUSIONS

The results obtained imply the efficiency of complementary methods to explain the absence or presence of (eco-)toxicological effects. In particular, methods that allow for single-organism analysis or provide even a spatial resolution support the interpretation of ecotoxicological findings.

Toxicological alterations induced by subacute exposure of silver nanoparticles in Wistar rats

Silver nanoparticles (AgNPs) have become crucial players in the field of medicine and various other industries. AgNPs have a wide array of applications, which includes production of electronic goods, cosmetics, synthesis of dyes, and printing inks, as well as targeted delivery of drugs to specialized cells inside the body. Even though humans readily come in contact with these particles, the organ-specific accumulation and resulting mechanisms of toxicity induced by inhaled AgNPs are still under investigation. The goal of this study was to determine the organ distribution of inhaled AgNPs and investigate the resulting systemic toxicity. To do this, male Wistar rats were exposed by inhalation to AgNPs for 4 hr/day (200 parts per billion/day) for five consecutive days. The nanoparticles were generated using a laser ablation technique using a soft-landing ion mobility (SLIM) instrument. Inductively coupled plasma mass spectrometric (ICP-MS) analysis showed organ-specific accumulation of the nanoparticles, with the highest concentration present in the lungs, followed by the liver and kidneys. Nanoparticle distribution was characterized in the organs using scanning electron microscopy (SEM) and matrix-assisted laser desorption/ionization mass spectrometric (MALDI-MS) imaging. Bone marrow cytotoxicity assay of the cells from the femur of rats showed micronuclei formation and signs of cellular cytotoxicity. Moreover, rats displayed increased levels of circulating lactate and glutathione disulphide (GSSG), as determined by liquid chromatography-mass spectrometry (LC-MS) analysis. Collectively, our observations suggest that inhaled subacute exposure to AgNP results in accumulation of AgNPs in the lungs, liver, and kidneys, preferentially, as well as mediates induced systemic toxicity.

Direct detection of solid inorganic mercury salts at ambient pressure by electron-capture and reaction-assisted HePI mass spectrometry

Solid HgCl2 is readily detected at ambient conditions by electron capture in a HePI-MS source. The captured electron occupies the empty 6 s orbital of the Hg atom. The resulting radical-anion HgCl2 (-•) can exist as three "flexomers" of different Cl-Hg-Cl angle. The facile in-source formation of HgCl2 (-•) and the adduct [HgCl3](--) is exploited to detect other solid Hg compounds by exposing them to an external chloride source, such as HCl, NaCl, or vapors emanating from solid TiCl3. In situ oxidation of Hg2Cl2 with H2O2 generated signals for HgCl2 (-•) and [HgCl3] (-), suggesting that oxidation makes Hg 6 s orbital available for electron capture.