Zinc- and Copper-Loaded Nanosponges from Cellulose Nanofibers Hydrogels: New Heterogeneous Catalysts for the Synthesis of Aromatic Acetals

Herein we report the synthesis of cellulose-based metal-loaded nano-sponges and their application as heterogeneous catalysts in organic synthesis. First, the combination in water solution of TEMPO-oxidized cellulose nanofibers (TOCNF) with branched polyethyleneimine (bPEI) and citric acid (CA), and the thermal treatment of the resulting hydrogel, leads to the synthesis of an eco-safe micro- and nano-porous cellulose nano-sponge (CNS). Subsequently, by exploiting the metal chelation characteristics of CNS, already extensively investigated in the field of environmental decontamination, this material is successfully loaded with Cu (II) or Zn (II) metal ions. Efficiency and homogeneity of metal-loading is confirmed by scanning electron microscopy (SEM) analysis with an energy dispersive X-ray spectroscopy (EDS) detector and by inductively coupled plasma-optical emission spectrometry (ICP-OES) analysis. The resulting materials perform superbly as heterogeneous catalysts for promoting the reaction between aromatic aldehydes and alcohols in the synthesis of aromatic acetals, which play a fundamental role as intermediates in organic synthesis. Optimized conditions allow one to obtain conversions higher than 90% and almost complete selectivity toward acetal products, minimizing, and in some cases eliminating, the formation of carboxylic acid by-products. ICP-OES analysis of the reaction medium allows one to exclude any possible metal-ion release, confirming that catalysis undergoes under heterogeneous conditions. The new metal-loaded CNS can be re-used and recycled five times without losing their catalytic activity.

Pollution and Potential Ecological Risk Assessment of Heavy Metals Around the Active Bukit Mendi Palm Oil Mill Area, Bera Pahang, Malaysia

The study on the impact of palm oil mill processing activities on the environment of Bukit Mendi Palm Oil Mill was conducted by determining the distribution of six heavy metal concentrations Cadmium (Cd), Copper (Cu), Manganese (Mn), Lead (Pb), Iron (Fe) and Zinc (Zn) and the selected pollution indices. This study provided some information on the accumulation of heavy metals in the selected area and served to identify the potential sources contributing to these heavy metals. Soil samples were collected from eight sampling sites around the palm oil mill and analysed for the selected metals using ICP-OES. Three types of pollution indices were used to observe the pollution level of the area, namely Enrichment Factor (EF), potential ecological risk index (PERI), and Contamination Factor (CF) of heavy metal content. The average total concentration of the selected metals was found to increase in the order of Fe, Mn, Zn, Cd, Pb, and Cu. The metal Fe showed the highest metal content, followed by Mn at 1573.00 mg/kg and 154.00 mg/kg, respectively. The values of EF showed that the metal was unevenly distributed throughout the sampling areas, where heavy metal content ranged from minimal to extremely high enrichment. The potential ecological risk ranging from low to severe was observed in this study. The CF values revealed that the area was heavily contaminated with Cd and only slightly contaminated with Pb. The pollution indices determined in this study suggested that the study area was moderately contaminated with metals, and the metal Cd was found to be the only metal potentially posing an ecological risk to the area.Keywords: ICP-OES, palm oil mill, heavy metals, soil pollution, pollution indices

An Inductively Coupled Plasma Optical Emission Spectrometric Method for the Determination of Toxic and Nutrient Metals in Spices after Pressure-Assisted Digestion

The aim of this study was to develop a simple and rapid inductively coupled plasma optical emission spectrometric (ICP-OES) method for the determination of 17 metals (Ag, Al, B, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Tl and Zn) in packaged spices. For this purpose, the spice samples (200 mg) in the form of powder were submitted to pressure-assisted wet-acid digestion with a mixture of 6 mL concentrated HNO3 and 1 mL H2O2. The proposed method was validated in terms of linearity, trueness, precision, limits of detection (LODs) and limits of quantification (LOQs). Good method trueness, precision and linearity were observed for the examined elements. The LODs of the examined analytes ranged between 0.08 and 5.95 mg kg−1. The present method was employed for the analysis of twenty-two packaged commercially available spices including asteroid anise, clove, cardamon, cinnamon, curry, coriander, turmeric, cumin, white pepper, black pepper, nutmeg, allspice, red pepper, paprika, ginger, green pepper and pink pepper from the Greek market that are widely consumed. A wide variety of metal of different concentration ranges were determined in the samples.

Rapid SABRE Catalyst Scavenging Using Functionalized Silicas

In recent years the NMR hyperpolarisation method signal amplification by reversible exchange (SABRE) has been applied to multiple substrates of potential interest for in vivo investigation. Unfortunately, SABRE commonly requires an iridium-containing catalyst that is unsuitable for biomedical applications. This report utilizes inductively coupled plasma-optical emission spectroscopy (ICP-OES) to investigate the potential use of metal scavengers to remove the iridium catalytic species from the solution. The most sensitive iridium emission line at 224.268 nm was used in the analysis. We report the effects of varying functionality, chain length, and scavenger support identity on iridium scavenging efficiency. The impact of varying the quantity of scavenger utilized is reported for the three scavengers with the highest iridium removed from initial investigations: 3-aminopropyl (S1), 3-(imidazole-1-yl)propyl (S4), and 2-(2-pyridyl) (S5) functionalized silica gels. Exposure of an activated SABRE sample (1.6 mg mL−1 of iridium catalyst) to 10 mg of the most promising scavenger (S5) resulted in <1 ppm of iridium being detectable by ICP-OES after 2 min of exposure. We propose that combining the approach described herein with other recently reported approaches, such as catalyst separated-SABRE (CASH-SABRE), would enable the rapid preparation of a biocompatible SABRE hyperpolarized bolus.

Nickels and tines: the myth of nickel allergy in intracranial stents

BackgroundMost intracranial stents contain nickel alloy, and nickel allergy or hypersensitivity is common. Neurological injury following endovascular treatment with a nickel containing intracranial stent has been reported in patients with purported nickel allergy, but it is unclear whether these reactions represent true nickel hypersensitivity. We quantified nickel release from commonly used intracranial stents to investigate whether such stents should be avoided in patients with nickel allergy.MethodsWe examined nickel release from seven commonly used intracranial stents: Enterprise, LVIS Jr, Neuroform, Wingspan, Zilver, Pipeline Flex Embolization Device, and Surpass Evolve. We incubated each stent in human plasma-like media for 30 days. Dimethylglyoxime (DMG) spot testing was performed on each stent to detect released nickel at 0 and 30 days. Inductively coupled plasma–optical emission spectroscopy (ICP-OES) was then used to quantify the nickel concentration of the media at 30 days. Nickel currency and nickel standard for atomic absorption spectrometry were used as positive controls.ResultsDMG spot tests indicated nickel release only from nickel currency at 0 and 30 days of incubation. No nickel release was detected from any stent at 30 days using ICP-OES.ConclusionsNickel release from commonly used intracranial stents is negligible. These results suggest that previously reported hypersensitivity to these stents may be misattributed to nickel allergy, and that patients with nickel allergy may be safely treated with select nickel-containing stents.

Utilization of ionic liquid for ICP-OES based trace metal assay in thorium matrix for decrease in liquid organic waste, cost, human exposure and time of analysis

Ionic liquid based 'Green" separation methodology was used for drastic reduction in organic phase requirement, generation of organic liquid waste, time of analysis, personal exposure towards radiotoxic environment, less chances...

Comparative Evaluation of Anti-Corrosion Coatings for NdFeB-Type Magnets with Respect to Performance and Recyclability via Hydrogen-Assisted Recycling (HPMS)

Various anti-corrosion coatings used on commercially available NdFeB-type magnets were comparatively examined for their durability and suitability for magnet reprocessing by hydrogen-assisted recycling (HPMS). Layer thickness and structure were determined by systematic microstructural analysis, and a standardized corrosion test was used to assess the durability of each layer. Chemical composition of the coatings was analyzed using SEM/EDS and ICP-OES. HPMS behavior was investigated using in situ video monitoring. The results of the presented investigations are an important contribution for the implementation of a sorting and labeling system to support and facilitate a commercially viable recycling of permanent magnets on an industrial scale.

Nutrient composition and bioaccumulation of an edible aquatic insect, Pantala sp. (Odonata: Libellulidae) from the rice field

Numerous edible aquatic insects have unanticipated nutraceutical potential and are consumed in a variety of Thai locations. The proximate composition, amino acid, fatty acid, mineral, and heavy metal content of Pantala sp. (Odonata: Libellulidae) aquatic edible nymphs were determined using standard analytical methods in this study. Pantala sp. had a proximate protein content of 445.14±0.04%, a fat content of 4.93±0.05%, an ash content of 5.24±0.03%, a moisture content of 35.11±0.09%, and a total carbohydrate content of 9.60±0.11%. Total energy was 263.25±0.20 kcal/100 g, with fat energy accounting for 44.37±0.43 kcal/100 g. Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) analysis revealed that this insect was high in phosphorus, iron, and copper for human consumption. In comparison to other edible insects studied, they were also excellent calcium sources. Agilent 7890B Gas Chromatograph (GC) analysis revealed that it contains 236.67 mg/100g of omega-3 and 523.32 mg/100g of omega-6. While the amino acids examined using High Performance liquid Chromatography contained all essential amino acids. ICP-OES was used to determine the levels of cadmium (Cd), lead (Pb), and arsenic (As). Pantala sp. had the highest concentration of As (average = 2.827 ± 0.289 mg kg -1 ), followed by Cd (0.164 ± 0.007 mg kg -1 ) and Pb (0.158 ± 0.015 mg kg -1 ). Although the insects have nutraceutical potential, they also have toxic heavy metals in trace amounts, with the exception of As. This work could serve as a nutritional reference for local consumers interested in entomophagy.