An environmental friendly enrichment method for microextraction of cadmium and lead in groundwater samples: Impact on biological sample of children

Determination of toxic elemental levels in whey milk of different cattle and human using an innovative digestion method: risk assessment for children < 6.0 months to 5 years

In present study, the toxic elements, arsenic (As), cadmium (Cd), and lead (Pb), were determined in whey milk samples obtained from various cattle (cow, goat, buffalo, sheep, camel) and human subjects of different areas of Sindh, Pakistan, based on consuming drinking water (exposed area) and surface water (control/non-exposed area). The whey milk was separated from casein by lowering the pH, and heating in an ultrasonic bath at 60 °C for 5 min and centrifuged. The whey milk samples were treated with deep eutectic solvent, prepared from choline chloride-oxalic acid (ChCl-Ox) at different mole ratio. Effects of different parameters on digestion efficiency of whey milk samples, including time and temperature of electric hot plate, mole ratio, and volumes of deep eutectic solvent were examined. The total levels of all selected toxic elements were also detected in whole milk samples of all exposed and nonexposed cattle and human, after acid digestion method. The validity of the proposed method was established by a conventional acid digestion method of selected whey milk samples and spiked certified standards in replicate real whey milk samples. The resulted elements obtained after proposed and conventional heating system were determined by inductively coupled plasma-optical emission spectrometry. The % of all three toxic elements found in whey milk samples were 24 to 50% of their total content in milk samples of different cattle and human. The As, Cd, and Pb contents in cattle and human milk consumed contaminated groundwater was significantly higher (2- to 3-fold) than those values observed for milk samples of cattle, who receive drinking water from fresh canal water (p < 0.01). Estimating the daily intake, hazard quotient and carcinogenic risk for <6 month to 5 years old children, based on the concentrations of toxic elements in milk samples of different cattle and human..

Mercapto-functionalized ordered mesoporous silica-modified PVDF membrane for efficiently scavenging Cd2+ from water

In this study, (3-mercaptopropyl) triethoxysilane (MPTMS)-modified ordered mesoporous silica (OMS) materials were prepared using a post-grifting method, with MPTMS as the organic functionalized reagent. The OMS materials were analyzed by FT-IR spectra, N₂ sorption, and small angle X-ray scattering to evaluate their potential for scavenging Cd²⁺ from water. Moreover, a (3-mercaptopropyl) triethoxysilane-functionalized ordered mesoporous silica modified polyvinylidene fluoride (MPTMS-OMS/PVDF) membrane was synthesized using the solvent phase inversion method to remediate wastewater containing heavy metal ions. The MPTMS-OMS was characterized by a maximum specific surface area of 422 m²/g, high surface hydrophilicity, and high pure water flux. The MPTMS-OMS/PVDF exhibited a dynamic adsorption capacity for Cd²⁺ in water. At an MPTMS-OMS content of 5 wt%, the Cd²⁺ removal efficiency was 90%, whereas the pure PVDF showed no Cd²⁺ adsorption capacity. These results highlight the potential of the MPTMS-OMS/PVDF membrane to eliminate Cd²⁺ during the decontamination of aqueous streams containing low-concentrations of contaminants.

Trends in microextraction approaches for handling human hair extracts - A review

The complementary role of hair in testing scenarios has expanded across the spectrum of toxicological and clinical monitoring investigations and, over the last 20 years, hair analysis has gained increasing attention and recognition. Moreover, a great deal of attention has been paid to the miniaturisation of extraction procedures, minimising/eliminating toxic organic solvents consumption, making them user-friendly and rapid, in addition to maximising extraction efficiency. The aim of this work is to provide a critical review of the advances observed over the last 5 years in the use of miniaturised approaches for sample clean-up and drug pre-concentration in hair analysis. There have been major improvements in some well-established microextraction approaches, such as liquid phase microextraction, mainly through the use of supramolecular and ionic liquids. In addition, new developments have also been reported in solid phase microextraction, driven by d-SPE applications. In the last 5 years, a total of 69 articles have been published using some type of microextraction technique for hair specimens, thus justifying the relevance of a critical review of innovations, improvements and trends related to these miniaturised approaches for sample preparation.

Boosting sensitive and selective detection toward Pb(II) via activation effect of Co and orbital coupling between Pb and O over Co@Co3O4 nanocatalyst

Fruitful achievements on electrochemical detection toward Pb(II) have been achieved, and their good performance is generally attributed to the adsorption property of nanomaterials. However, the design of sensing interfaces from the electronic structure and electron transfer process is limited. Here, Co@Co₃O₄ acquired an ultra-high detection sensitivity of 103.11 µA µM^-1 toward Pb(II), outperforming the results previously reported. The interfacial oxygen atoms build an electron bridge for Co activating Co₃O₄. Particularly, new energy levels of oxygen atoms were generated and matched with that of Pb(II). The strong orbital coupling effect between O and Pb makes the Co@Co₃O₄ sensitive and selective toward Pb(II). Compared with Co metal and Co₃O₄, Pb(II) got more electrons from Co@Co₃O₄, and longer Pb-O bonds were formed, allowing more Pb(II) to be catalyzed and reduced. Also, the superior stability and reproducibility of electrochemical detection make electrodes practicably. This work reveals that metals can stimulate intrinsically catalytic activity of their metal oxides, with the generation of orbit energy levels that match to a specific analyte. It provides a promising strategy for constructing sensitive and selective sensing interfaces toward ultra-low concentration analyte in body fluid and other complex samples.

Determination of prohibited lead and cadmium traces in hair dyes and henna samples using ultrasound assisted-deep eutectic solvent-based liquid phase microextraction followed by microsampling-flame atomic absorption spectrometry

In this study ultrasound assisted-deep eutectic solvent-based liquid phase microextraction followed by microsampling-flame atomic absorption spectrometry was developed to determine prohibited lead and cadmium traces in hair dye and henna samples. For this purpose, deep eutectic solvent, prepared from choline chloride and phenol, was used as an extraction solvent, dithizone was used as a complexing agent, and THF was used as an aprotic solvent. All parameters that affect extraction efficiency, such as pH, the DES volume and composition, the extraction time, the amount of dithizone, were optimized. Under the optimal conditions, for Pb(ii) and Cd(ii), enhancement factors of 92 and 57, LODs of 2.5 μg L^-1 and 0.75 μg L^-1, LOQs of 7.8 μg L^-1 and 2.5 μg L^-1, linear working ranges of 10-250 μg L^-1 and 2.5-50 μg L^-1, were obtained, respectively. Relative standard deviation (n = 10) was calculated to be 2.7 for 100 μg L^-1 of Pb(ii) and 2.1 for 25 μg L^-1 of Cd(ii). The matrix effect was investigated by comparing the solvent-based calibration curve with the matrix-matched calibration curve. The determination of lead and cadmium in hair dye and henna samples without being affected by the sample matrix was successfully performed. The lead content was between 1.3 and 6.5 μg g^-1, and the cadmium content was between 0.028 and 0.54 μg g^-1 for the selected hair dye and henna samples.

Sequential removal and recovery of cadmium ions (Cd2+) using photocatalysis and reduction crystallization from the aqueous phase

The removal of cadmium ions using photocatalysis, reduction crystallization and their sequencial system.

Removal of aqueous-phase lead ions by dithiocarbamate-modified hydrochar

Hydrochar produced from agricultural and forestry wastes and its application into the environment are very attractive. Herein, a high-efficiency dithiocarbamate-modified hydrochar (DTHC) was prepared successfully and then applied to eliminate Pb(II) from aqueous solutions. DTHC was characterized by various techniques. It was found that dithiocarbamate and amine groups were successfully grafted onto the surface of hydrochar. The surface area of DTHC was 7.94 m²·g^-1, which was four folds less than pristine hydrochar (31.60 m²·g^-1), but its adsorption capacity obviously increased. Adsorption experiments showed that the Pb(II) adsorption process onto DTHC well accorded with pseudo-2nd-order kinetics and Langmuir isotherms. The highest Pb(II) uptake by DTHC at 293 K determined from the Langmuir model was 151.51 mg·g^-1. Fourier transform infrared spectra and X-ray photoelectron spectroscopy verified that dithiocarbamate, carboxylate, amine and sulfonate groups all facilitated the Pb(II) adsorption. The adsorption mechanism was ascribed to the inner-sphere surface complexation of Pb(II) by these groups and to the ion exchange between Pb(II) and Na(I). Thus, DTHC is an effective adsorbent for Pb(II) removal from water.