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Essential and non-essential elements, and volatile organic compounds for the discrimination of twenty-three sweet cherry cultivars from Fundão, Portugal

Date: 2022
Authors: Gonçalves, AC;Campos, G;Pinto, E;Oliveira, AS;Almeida, A;de Pinho, PG;Alves, G;Silva, LR;
References: Food chemistry 367 130503
Keywords/Products: iCAP;ICP;ICP-MS;Meinhard;Thermo;
The mineral contents and volatile profiles of 23 sweet cherry cultivars were determined. A total of 27 minerals were determined by ICP-MS and flame atomic absorption spectrometry, including 12 essential and 15 non-essential elements. K was the most abundant in all cultivars, while Tl was the one found in the smallest amounts. A total of 66 volatiles were identified using SPME/GC-MS, including 16 aldehydes, 23 alcohols, 6 ketones, 6 esters, 8 monoterpenes, 3 norisoprenoids, 2 hydrocarbons and 2 acids. Benzaldehyde, hexanal, nonanal, benzyl alcohol, (E)-2-hexen-1-ol, 1-hexanol, (Z)-2-hexen-1-ol, 2-ethyl-1-hexanol, linalool, ?-terpineol and ?-ionone were the major ones. Qualitative and quantitative differences were observed among the cultivars, which influenced nutritional potential and aroma. Cherries from Fundão region contain high concentrations of phytochemicals and nutritional components. 4-84, Burlat and Celeste might be considered some of the most interesting cultivars, since they are rich in essential minerals and present high diversity in volatiles.

Use of single particle inductively coupled plasma mass spectrometry for understanding the formation of bimetallic nanoparticles

Date: 2022
Authors: Heetpat, N;Sumranjit, J;Siripinyanond, A;
References: Talanta 236 122871
Keywords/Products: Concentric;ICP;ICP-MS;Meinhard;NexION;Type C;
Bimetallic nanoparticles (NPs), including core-shell structure and bimetallic alloy nanoparticles, were synthesized and characterized using flow field-flow fractionation (FlFFF), single particle inductively coupled plasma mass spectrometry (SP-ICP-MS), and transmission electron microscope (TEM) with energy-dispersive x-ray spectroscopy (EDS). For the core-shell particles, a nominal 80 nm commercial core-shell AuAg bimetallic nanoparticle was used to examine the applicability of SP-ICP-MS to determine the core size of Au and shell thickness of Ag. Then, the method was applied to estimate the core size of Au and shell thickness of Ag for the laboratory synthesized particles. The results were compared with those obtained from TEM-EDS. For the alloy nanoparticles, two synthesis protocols, based on the galvanic replacement of Ag seed particles with Au, were used. One was to prepare a hollow AgAu particle by varying the volume of dissolved Au in basic solution (K-gold) to etch some parts of AgNPs to dissolved ionic silver with the formation of AuNPs covering the remaining AgNPs, producing a hole inside the core nanoparticles. Another protocol was to prepare AgAu alloy nanoparticles. SP-ICP-MS was used in combination with FlFFF to provide information on the changes of particle size with varying volume of K-gold reagent. Hydrodynamic diameter increased with increasing K-gold, as observed by FlFFF. With SP-ICP-MS without prior FlFFF, bimodal distributions were observed in the size distribution of Au and Ag. With prior FlFFF, monomodal distributions were observed by SP-ICP-MS, which allow the use of particle concentration and size to estimate the mass concentration of elements on the fractionated bimetallic nanoparticles. This study illustrates the potential use of SP-ICP-MS for gaining information about particle transformation during the synthesis of bimetallic nanoparticles.

Titanium dioxide nanoparticles assessment in seaweeds by single particle inductively coupled plasma - Mass spectrometry

Date: 2022
Authors: López-Mayán, J;del-Ángel-Monroy, S;Peña-Vázquez, E;Barciela-Alonso, M;Bermejo-Barrera, P;Moreda-Piñeiro, A;
References: Talanta 236 122856
Keywords/Products: Concentric;ICP;ICP-MS;Meinhard;
In this study, a first attempt for isolating and determining (characterising) background levels of titanium dioxide nanoparticles (TiO2 NPs) in seaweed has been developed by using single particle inductively coupled plasma - mass spectrometry (SP-ICP-MS). Seaweeds were processed using an optimised ultrasound assisted extraction (UAE) procedure based on tetramethylammonium hydroxide (TMAH) before dilution and SP-ICP-MS analysis. The effect of the TMAH percentage in the extracting solution, as well as the volume of extracting solution and sonication (extraction) time, has been fully assessed. Additional experiments also showed that TiO2 NPs were quantitatively released from the seaweed matrix in one UAE step since the analysis of residues gave TiO2 NPs concentrations lower than the limit of quantification (LOQ) of the method. Validation of the method with 50 and 100 nm TiO2 NPs (10 ?g L?1 as Ti) showed good analytical recovery (115% and 112% for 50 and 100 nm TiO2 NPs, respectively), and good reproducibility (2% for size and 16% for number of TiO2 NPs). Experiments regarding TiO2 NPs stability showed that the extracted NPs are stable since there were not changes on the number of TiO2 NPs and TiO2 NPs size distributions when exposing TiO2 NPs standards to the optimised extractive conditions.

Gravitational assisted three-stage block freeze concentration process for producing enriched concentrated orange juice (Citrus sinensis L.): Multi-elemental profiling and polyphenolic bioactives

Date: 2022
Authors: Haas, I;Espindola, J;de Liz, G;Luna, A;Bordignon-Luiz, M;Prudêncio, E;de Gois, J;Fedrigo, I;
References: Journal of Food Engineering 315 110802
Keywords/Products: Concentric;Concentric nebulizer;iCAP;Meinhard;Thermo;
A three-stage block freeze concentration process using minimal instrumental apparatus was studied to concentrate minerals and polyphenols in orange juice, obtaining one cryoconcentrate and one ice fraction at each stage. The process parameters were designed, and the cryoconcentrates and ice fractions were analyzed for physicochemical properties, polyphenolic composition, and mineral profile. The three-stage process obtained high concentrations of polyphenols and minerals in orange juice, with the third stage cryoconcentrate obtaining a 429% increase in polyphenols compared to the initial juice. This cryoconcentrate had the highest K, Mg, and Ca levels, while most of the minerals were significantly retained in the ice fractions. The antioxidant activity of concentrated juices increased sequentially by 168, 272, and 343% across process stages. The last two stages of cryoconcentration using only gravitational force led to high concentrations of polyphenols, minerals, soluble solids, and vitamin C in concentrated juices.

Tracking changes in rhodium nanoparticles in the environment, including their mobility and bioavailability in soil

Date: 2022
Authors: Kowalska, J;Biadu?, E;Ki?ska, K;Gniadek, M;Krasnod?bska-Ostr?ga, B;
References: The Science of the total environment 806 151272
Keywords/Products: ICP;Meinhard;NexION;Perkin Elmer;
The goals of the undertaken studies included assessment of the mobility of Rh nanoparticles (Rh NPs) and ionic forms (Rh(III)) in soil, optimization of the digestion procedure of environmental samples containing Rh NPs, and comparison of Rh NPs and Rh(III) uptake and bioaccumulation by hydroponically cultivated plants. Mass spectrometry with inductively coupled plasma (ICP MS) was used to determine the total content of Rh in solutions obtained after the processes of digestion and extraction. Transmission Electron Microscopy (TEM) supported the investigation of Rh NPs decomposition and proved the presence of uptaken nano forms in plant tissues. Adsorptive stripping voltammetry (AdSV) allowed to distinguish ionic and metallic forms of Rh, based on the fact that Rh NPs are electrochemically inactive. A two-step digestion procedure with H2SO4 and HNO3 was proposed for efficient decomposition of Rh NPs. Based on single extractions with selected extractants, it was found that independently of its chemical form Rh is substantially immobilized in soil. The mobility of Rh(III) and Rh NPs was below 38% and 0.02%, and the accumulation factor in leaves equaled 0.2 and 4.4, respectively.

Strawberry (Fragaria × ananassa cv. Romina) methanolic extract attenuates Alzheimer's beta amyloid production and oxidative stress by SKN-1/NRF and DAF-16/FOXO mediated mechanisms in C. elegans

Date: 2022
Authors: Navarro-Hortal, MD;Romero-Márquez, JM;Esteban-Muñoz, A;Sánchez-González, C;Rivas-García, L;Llopis, J;Cianciosi, D;Giampieri, F;Sumalla-Cano, S;Battino, M;Quiles, JL;
References: Food chemistry 372 131272
Keywords/Products: Agilent;ICP;ICP-MS;Meinhard;
Bioactive compounds from strawberries have been associated with multiple healthy benefits. The present study aimed to assess chemical characterization of a methanolic extract of the Romina strawberry variety in terms of antioxidant capacity, polyphenols profile and chemical elements content. Additionally, potential toxicity, the effect on amyloid-? production and oxidative stress of the extract was in vivo evaluated in the experimental model Caenorhabditis elegans. Results revealed an important content in phenolic compounds (mainly ellagic acid and pelargonidin-3-glucoside) and minerals (K, Mg, P and Ca). The treatment with 100, 500 or 1000 ?g/mL of strawberry extract did not show toxicity. On the contrary, the extract was able to delay amyloid ?-protein induced paralysis, reduced amyloid-? aggregation and prevented oxidative stress. The potential molecular mechanisms present behind the observed results explored by RNAi technology revealed that DAF-16/FOXO and SKN-1/NRF2 signaling pathways were, at least partially, involved.

Determination of photon-driven charge transfer efficiency: Drawbacks, accuracy and precision of different methods using Hematite as case of study

Date: 2022
Authors: Bedoya-Lora, F;Valencia-García, M;Hankin, A;Klotz, D;Calderón, J;
References: Electrochimica Acta 402 139559
Keywords/Products: Meinhard;
The electrochemical properties of photoelectrodes must be measured accurately and precisely to enable better comparisons between different materials. Along with the flat band potential, the interfacial charge transfer efficiency, which is the ratio between charge transfer rate at the photoelectrode surface and rate of charge carrier generation in the photoelectrode, can be used to predict the current density response at a given photon flux and electrode potential. The most widely used techniques for measuring charge transfer efficiencies are Photo-Electrochemical Impedance Spectroscopy (PEIS), current density ratios in the presence and absence of hole/electron scavengers, chrono-amperometry and Intensity Modulated Photocurrent Spectroscopy (IMPS). Charge transfer efficiencies can be estimated from PEIS and IMPS spectra either by using raw data (graphically), by fitting equivalent electrical circuits or by computing the Distribution of Relaxation Times (DRT). However, these techniques have their own drawbacks and impracticalities, that require researchers to make a choice between measuring accurately or pragmatically. Hitherto, the theoretical and experimental details of these techniques have not been summarised collectively and comprehensively. Here, we report the benefits and drawbacks, the accuracy, precision and best experimental recommendations when employing different techniques for photon-driven charge transfer efficiency determination.

Comparison of different winemaking processes for improvement of phenolic composition, macro- and microelemental content, and taste sensory attributes of Teran (Vitis vinifera L.) red wines

Date: 2022
Authors: Rossi, S;Bestuli?, E;Horvat, I;Plavša, T;Luki?, I;Bubola, M;Gani?, K;?urko, N;Jagati? Korenika, A;Radeka, S;
References: LWT 154 112619
Keywords/Products: Meinhard;POINT;
The effect of four different winemaking processes on phenolic compounds, macro- and microelements, and taste sensory attributes of Teran red wines was studied. The study covered seven days of maceration as a control (TM7), prolonged 10-day maceration (TM10), prolonged post-fermentative 21-day maceration (TM21), and 48-h pre-fermentative maceration heating at 45 °C followed by eight-day standard maceration (TPHT). Phenolic compounds were analyzed using high-performance liquid chromatography with UV-Vis diode array and fluorescence detection. Analysis of macro- and microelements was conducted by inductively coupled plasma - optical emission spectrometry. Sensory profiles of wine samples were obtained using quantitative descriptive analysis and the 100-point O.I.V./U.I.O.E. method. The results showed a significant increase of 25% in total flavan-3-ols content in TM21 wine. The concentrations of hydroxybenzoic acids increased significantly upon TM21 and TPHT treatment, while particular hydroxycinnamic acids showed a significant increase after TPHT treatment. The obtained results showed differences in the content of macro- and microelements, with significantly higher values of particular elements in TM21 and TPHT wines. Sensory analysis results corresponded to the chemical content of the wines to a great extent. The findings showed that TM21 and TPHT treatments have a positive influence on the taste attributes of the investigated wines.

Decoupling of isotopes between magmatic zircons and their mafic host rocks: A case study from the ca. 830 Ma Jiabang dolerite, South China

Date: 2022
Authors: Wu, T;Wang, X;Wilde, S;Li, Q;Pang, C;Zhou, J;
References: Precambrian Research 369 106519
Keywords/Products: Glass Nebulizer;ICPMS;Meinhard;
Zircon is widely used to constrain the crystallization age and magma source of the host rocks. However, in recent years an increasing number of studies have demonstrated that Hf-O isotopes of zircon grains are not always in equilibrium with the whole-rock isotopes of the host rocks. Here we present a case from the Jiabang dolerite from southeastern Guizhou Province, South China, to demonstrate the decoupling of isotopes between magmatic zircons and their mafic host rocks as a result of limited crustal contamination. In-situ SIMS U-Pb zircon dating shows that the Jiabang dolerite formed at 838 ± 7 Ma. The Jiabang dolerite has low SiO2 of 47.6 - 54.2 wt%, high MgO of 4.93 - 15.6 wt%, and Fe2O3 of 8.51 - 11.9 wt%, typical of mantle-derived magma. All whole-rock samples in this study have depleted Nd-Hf isotopes, with ?Nd(t) values ranging from + 2.6 to + 3.8 and ?Hf(t) values from + 6 to + 10, with whole-rock ?Nd(t) values similar to those of contemporary OIB-like mantle-derived melts in South China. Such whole-rock chemical features imply that the source of the Jiabang dolerites is mantle-dominated and that any crustal contribution should be insignificant. However, zircons from the dolerite display negative ?Hf(t) values of ?6 to ?1 and high ?18O values of 9.7-11.5 ‰ that are similar to those of the Guibei granitoids in the study area, suggesting a crustal origin. Our AFC simulation based on Magma Chamber Simulator (MCS) demonstrates that AFC played a limited role in the generation of the Jiabang dolerite and indicates that the decoupling between zircon Hf-O and the whole-rock Nd-Hf isotopes likely reflects a contribution from wallrock-derived melts during emplacement of the dolerites. We propose that the zircons crystallized in interstitial liquids that were contaminated by crustal-derived fluids/melts, resulting in decoupling between the whole-rock isotopes and the magmatic zircon isotopes. Due to mass balance requirements, the crustal melts/fluids would have insignificant effect on the whole-rock isotopes, but will strongly modify the Hf-O isotopes of zircons that crystallized in the interstitial liquids. This case study shows that caution needs to be applied when comparing zircon Hf-O isotopes from mafic intrusive rocks to constrain their source.

X-ray fluorescence analysis of air particulate matter generated at a welding site

Date: 2022
Authors: Ghosh, M;Biswas, S;Swain, K;
References: Spectrochimica Acta Part B: Atomic Spectroscopy 187 106328
Keywords/Products: Concentric;Concentric nebulizer;Meinhard;
The air particulate matter generated during welding operations is a major health concern for the welders as they trigger respiratory diseases. The information on elemental composition of the air particulate matter is required to know the toxicity as it depends on the constituent elements. We report the rapid analysis of air particulate matter at welding site, collected on whatman-41 filter paper. Internal standard method was used for the quantification of the elements both in energy dispersive X-ray fluorescence (EDXRF) and total reflection X-ray fluorescence (TXRF) spectrometry. In EDXRF, the sample was found to be thin for the elements Z > 29 and intermediate thickness for the elements 28 ? Z ? 19 and thick for elements of Z ? 17. About 17 elements were detected in air particulate matter and out of which Al, Si, Ca and Fe share the highest contribution. The composition of particulate matter is modulated by the composition of the welding material and the adjacent construction activities. The combined uncertainty in XRF was evaluated by identifying all the uncertainty sources. The study showed fast, non-destructive analysis capability of EDXRF and TXRF as an excellent micro-analytical technique for the air particulate samples.Nebulizer Meinhard Concentric Nebulizer Concentric

Short exposure to ethyl and methylmercury prompts similar toxic responses in Drosophila melanogaster

Date: 2022
Authors: Wildner, G;Loreto, JS;de Almeida, P;Claro, MT;Ferreira, SA;Barbosa, NV;
References: Comparative biochemistry and physiology. Toxicology & pharmacology : CBP 252 109216
Keywords/Products: Concentric;Concentric nebulizer;ELAN;Meinhard;
Methylmercury (MeHg) and ethylmercury (EtHg) are important mercury organic forms in terms of human poisoning. Since the comparative effects of compounds are mainly in vitro, this study was designed to investigate the toxicities induced by MeHg and EtHg in an in vivo study using adult Drosophila melanogaster (D. melanogaster). Firstly, we performed a survival curve, where the flies were fed on a medium containing MeHg and EtHg at concentrations ranging from 2.5 to 200 ?M, until the end of their lifespan. After that, the concentrations 25 and 200 ?M of MeHg and EtHg were chosen to be tested in a short exposure for 5 days. The analysis of survival by Kaplan-Meier plot revealed that all concentrations of MeHg and EtHg reduced significantly the lifespan of the flies. Short exposure to both concentrations of MeHg and EtHg impaired the ability of flies in the climbing assay and induced lipid peroxidation. Only the flies exposed to the highest concentration had viability loss, thiol depletion, and increased reactive species (RS) and Hg levels in the whole body. Our findings indicate that MeHg and EtHg exhibit similar toxic effects in vivo, and that oxidative stress is a phenomenon behind the toxicity of both mercurials. The data obtained also reinforce the use of D. melanogaster as a useful organism for basic toxicological research.

Bioactivity, volatile profile, and physicochemical properties of set?type yogurt enriched with European cranberrybush ( Viburnum opulus L.) juice during storage

Date: 2022
Authors: Taspinar, T;Güven, M;A?çam, E;
References: Journal of Food Processing and Preservation 46 1
Keywords/Products: Concentric;Meinhard;Quartz Nebulizer;
This study aimed to investigate the effect of using European cranberrybush (EC; Viburnum opulus L.) juice at three different concentrations (4%, 8%, 12%) on the quality attributes and shelf life (28 days, 4°C) of the yogurts. The addition of EC juice to yogurts promoted a significant increase in all bioactive components of the yogurts. Thirty-seven volatiles were identified as acids, aldehydes, ketones, terpenes, esters, and alcohols. According to texture results, yogurts acted less firmly and consistently based on rising in EC juice concentration. In addition, the scanning electron microscopy results showed that with the addition of EC juice yogurt has a less compact network structure and bigger pores. The principal component analysis revealed that yogurts were distributed at least three quadrants of the score plot at each storage day and also in the preference map the samples were located in different percentages.

Emission Spectra of Hydrocarbon Flames Doped with Phosphorus-Containing Compounds

Date: 2022
Authors: Turner, M;Parajuli, P;Kulatilaka, W;Petersen, E;
References: AIAA SCITECH 2022 Forum 1 1
Keywords/Products: DIHEN;Glass Nebulizer;Meinhard;
Phosphorus-containing compounds, including organophosphorus substances, are valuable laboratory flame additives for understanding the combustion behavior of sarin. Chemiluminescence features of excited intermediate species are useful markers of combustion, but an effective chemiluminescence-based combustion diagnostic for phosphorus-based compounds is yet to be developed. In this study, chemiluminescence spectra of atmospheric-pressure flames doped with three phosphorus-containing compounds, namely, dimethyl methylphosphonate (DMMP), diisopropyl methylphosphonate (DIMP), and phosphoric acid (H3PO4), were obtained in two flame configurations, namely, spherically expanding flames and piloted liquid-spray flames. The spectra are compared with those obtained from undoped flames fueled by methane and methanol, respectively. Spectra were recorded for the wavelength range of 200 to 800 nm and for three equivalence ratios (? = 0.8, 1.0, 1.2) of spherical flames. For both flame configurations, the intensity of the doped flame emission increased relative to the neat flames by over an order of magnitude, but no clear spectral features besides a broad, featureless continuum emission could be identified. No significant difference was observed between the spectra of the spray flames doped with H3PO4 and with DIMP. The observance of a continuum emission for all the doped flames is attributed to blackbody emission, likely resulting from high-temperature soot particles in the flame originating from condensed, phosphorus-containing combustion products. However, unique, narrow chemiluminescence features specific to phosphorus combustion could not be identified at this time.

Phase Behavior of Internal Mixtures of Hydrocarbon-like Primary Organic Aerosol and Secondary Aerosol Based on Their Differences in Oxygen-to-Carbon Ratios

Date: 2022
Authors: Mahrt, F;Huang, Y;Zaks, J;Devi, A;Peng, L;Ohno, PE;Qin, YM;Martin, ST;Ammann, M;Bertram, AK;
References: Environmental science & technology ~ ~
Keywords/Products: Aerosol;Meinhard;TR-30-C0.5;
The phase behavior, the number and type of phases, in atmospheric particles containing mixtures of hydrocarbon-like organic aerosol (HOA) and secondary organic aerosol (SOA) is important for predicting their impacts on air pollution, human health, and climate. Using a solvatochromic dye and fluorescence microscopy, we determined the phase behavior of 11 HOA proxies (O/C = 0-0.29) each mixed with 7 different SOA materials generated in environmental chambers (O/C 0.4-1.08), where O/C represents the average oxygen-to-carbon atomic ratio. Out of the 77 different HOA + SOA mixtures studied, we observed two phases in 88% of the cases. The phase behavior was independent of relative humidity over the range between 90% and <5%. A clear trend was observed between the number of phases and the difference between the average O/C ratios of the HOA and SOA components (?O/C). Using a threshold ?O/C of 0.265, we were able to predict the phase behavior of 92% of the HOA + SOA mixtures studied here, with one-phase particles predicted for ?O/C < 0.265 and two-phase particles predicted for ?O/C ? 0.265. The threshold ?O/C value provides a relatively simple and computationally inexpensive framework for predicting the number of phases in internal SOA and HOA mixtures in atmospheric models.

Occurrence, distribution, and associations of essential and non-essential elements in the medicinal and edible fungus 'Fuling' from southern China

Date: 2022
Authors: Zhang, J;Falandysz, J;Hanc, A;Lorenc, W;Wang, Y;Baralkiewicz, D;
References: Science of The Total Environment ~ 155011
Keywords/Products: Concentric;Concentric nebulizer;ELAN;Meinhard;
In Asian countries, the sclerotia of the wild-grown fungus Pachyma hoelen ('Fuling'), have been used as food and as medicinal products for centuries. To close the knowledge gaps about the value and possible environmental impacts, the occurrence, distribution, and associations of a range of elements (Ag, Al, As, Ba, Cd, Co, Cr, Cs, Cu, Li, Mg, Mn, Ni, Pb, Rb, Sb, Sr, Tl, U, V, and Zn) were studied in the inner (core) and outer (shell) morphological parts of the sclerotia from a diverse collection in Southern China. Quality of forest and agricultural soil in terms of a geogenic element source and composition can be considered as the main factor determining the occurrence of minerals in sclerotia through the host wood, largely of Pinus yunnanensis, while the anthropogenic impact (basically at remote rural areas of cultivation) in Southern China was negligible. In general, the mean concentration of each element in the outer part was significantly higher than that in the inner part (t-test, p?

Separation of heavy rare-earth elements by non-aqueous solvent extraction: Flowsheet development and mixer-settler tests

Date: 2022
Authors: Dewulf, B;Riano, S;Binnemans, K;
References: Separation and Purification Technology 290 120882
Keywords/Products: Meinhard;
The separation of rare-earth elements (REEs) is considered one of the most challenging processes in solvent extraction. In recent years, non-aqueous solvent extraction, a unit operation within solvometallurgy, has stepped into the limelight as one of the promising techniques for efficient REEs separation. In this paper, a rare-earth hydroxide concentrate, originating from mining waste and containing mainly heavy rare-earth elements (HREEs), was redissolved in ethylene glycol + 10 vol% water, 0.43 mol L?1 HCl and 0.8 mol L?1 NaCl. Based on batch experiments, a conceptual flowsheet was proposed for the separation of the HREEs into 2 groups: a thulium group (Tm, Yb and Lu) and a dysprosium group (Dy, Ho, Er and Y). Continuous solvent extraction tests in lab-scale mixer-settlers were performed to confirm the technical feasibility of the developed system, as well as to identify and resolve possible bottleneck points. Eventually, using only 16 stages of lab-scale mixer-settlers, the purity of the thulium group and dysprosium group elements, originally 34% and 54%, respectively, reached 99.8% and 98.7%, respectively. Further optimization remains necessary for the separation and purification into highly pure single REEs.

Laser ablation-single particle-inductively coupled plasma mass spectrometry as a sensitive tool for bioimaging of silver nanoparticles in vivo degradation

Date: 2022
Authors: Wang, M;Zheng, L;Wang, B;Yang, P;Fang, H;Liang, S;Chen, W;Feng, W;
References: Chinese Chemical Letters ~ ~
Keywords/Products: HEN;ICP;ICP-MS;Meinhard;sample introduction;
The in vivo degradation behavior of metallic nanoparticles (NPs) is very important for their biomedical applications and safety evaluation. Here, a method of laser ablation-single particle inductively coupled plasma mass spectrometry (LA-sp-ICP-MS) is shown to have high spatial resolution, sensitivity and accuracy for simultaneous imaging the in situ distribution of particulate Ag (P-Ag) and released ionic Ag (Ion-Ag) in the sub-organs of spleen, liver and kidney after intravenous injection of Ag nanoparticles (50-nm AgNPs) to mice. Under the optimized parameters of 0.4 J/cm2 laser fluence on a 30 ?m spot with dwell time at 100 ?s, the signals of P-Ag and Ion-Ag in the organic tissues can be easily distinguished from the mass spectra. The method of iterative threshold algorithm has been used to distract the signals of P-Ag and Ion-Ag and separate each other. The resulting images for the first time provide visualized evidence that a considerable amount of P-Ag accumulated in the splenic marginal zone, but widely distributed in the liver parenchyma at 24 h after injection of AgNPs, and in the meantime, obvious amounts of ionic Ag released and distributed in the organs. In addition, the imaging results indicate that the AgNP excretion in the kidney is mainly in ionic forms. The investigation here demonstrates that the developed LA-sp-ICP-MS method with high spatial resolution, sensitivity and visualization capability can become a powerful tool in the clinical context of metallic NPs.

Gold nanoclusters as elemental label for the sequential quantification of apolipoprotein E and metallothionein 2A in individual human cells of the retinal pigment epithelium using single cell-ICP-MS

Date: 2022
Authors: Lores-Padin, A;Mavrakis, E;Fernandez, B;Garcia, M;Gonzalez-Iglesias, H;Pereiro, R;Pergantis, SA;
References: Analytica chimica acta 1203 339701
Keywords/Products: HEN;ICP;ICP-MS;Meinhard;sample introduction;
Gold nanoclusters (AuNCs) with a diameter of 1.99 nm on average were synthesized and applied as labels in immunoprobes for the determination of cytosolic proteins in individual human retinal pigment epithelium (HRPEsv) cells by single cell - inductively coupled plasma - mass spectrometry (sc-ICP-MS). For quantitative purposes, the number of gold atoms per immunoprobe (i.e., the amplification factor) was determined; 466 gold atoms on average were obtained. Human metallothioneins (MT), including the 2A isoform (MT2A), and apolipoprotein E (APOE) play an important role under inflammation and oxidation processes in the RPE. The new single biomarker strategy introduced was applied to the sequential determination of MT2A and APOE in HRPEsv cells under pro-inflammatory and control conditions through the development of immunoassays with the corresponding AuNCs immunoprobes and the measurement of the 197Au+ signal by sc-ICP-MS. In addition, 56Fe+ signal was measured as constituent element of HRPEsv cells in order to check the integrity of the cells after the immunoassay and to confirm the number of cell events detected when monitoring the protein label (197Au+). Optimisation of parameters related with the sample preparation for the analysis of cytosolic proteins in intact HRPEsv cells was carried out. The method was successfully applied to the determination of both proteins in control cells and cells treated with the recombinant human interleukin-1?. Quantitative results obtained per cell for the average protein amounts of APOE and MT2A using the sc-ICP-MS procedure were corroborated with commercial ELISA kits.

Microwave-induced self-ignition: An efficient approach for high purity graphite digestion and multitechnique halogen determination

Date: 2022
Authors: Cruz, SM;Druzian, GT;Santos, RF;Mesko, MF;Duarte, FA;Flores, EMM;
References: Analytica chimica acta 1199 339569
Keywords/Products: Concentric;Concentric nebulizer;ELAN;ICP;ICP-MS;Meinhard;POINT;
In this work, high purity graphite, a high chemically stable material, was effectively digested using a single method allowing compatible solutions for the further multitechnique determination of halogens by: ion chromatography (F and Cl), inductively coupled plasma mass spectrometry (Cl, Br and I) and by ion selective electrode (only for F). The recent system using microwave-induced self-ignition (MISI) is based on the strong interaction between microwave radiation and graphite in a closed system pressurized with oxygen (Maxwell-Wagner effect). Carbon-based materials present intense and specific interfacial polarization when exposed to microwave electromagnetic field resulting in a fast heating rate. This effect associated to a pressurized oxygen system, provides a quick self-ignition of carbon-based materials and consequent combustion/digestion of organic matrices. Under optimized conditions, sample masses up to 600 mg were fully digested in a quartz vessel under 20 bar of oxygen pressure and using just a diluted solution (100 mmol L-1 NH4OH) for the quantitative absorption of all the analytes. MISI method was validated, and the accuracy (better than 94%) was evaluated by comparison of results obtained by pyrohydrolysis for two coal certified reference materials as well as with subsequent analytes determination by the three techniques: IC, ICP-MS and ISE. It is important to point out that no filter paper disks, electrical connections or other ignition aids are required as in the case of previous or classical combustion methods. Moreover, just a diluted absorbing solution was used resulting in negligible blanks and relatively low limits of detection. The digestion efficiency was higher than 99%, making the proposed method a suitable and powerful alternative for the quasi complete digestion of graphite and determination of halogens virtually free of interferences.

A novel approach for adapting the standard addition method to single particle-ICP-MS for the accurate determination of NP size and number concentration in complex matrices

Date: 2022
Authors: Aramendia, M;Garcia-Mesa, J;Alonso, E;Garde, R;Bazo, A;Resano, J;Resano, M;
References: Analytica Chimica Acta 1205 339738
Keywords/Products: Concentric;Concentric Quartz Nebulizer;Glass Nebulizer;ICP;ICP-MS;Meinhard;Quartz Nebulizer;sample introduction;Type A;Type C;
This paper presents a novel approach, based on the standard addition method, for overcoming the matrix effects that often hamper the accurate characterization of nanoparticles (NPs) in complex samples via single particle inductively coupled plasma mass spectrometry (SP-ICP-MS). In this approach, calibration of the particle size is performed by two different methods: (i) by spiking a suspension of NPs standards of known size containing the analyte, or (ii) by spiking the sample with ionic standards; either way, the measured sensitivity is used in combination with the transport efficiency (TE) for sizing the NPs. Moreover, such transport efficiency can be readily obtained from the data obtained via both calibration methods mentioned above, so that the particle number concentration can also be determined. The addition of both ionic and NP standards can be performed on-line, by using a T-piece with two inlet lines of different dimensions. The smaller of the two is used for the standards, thus ensuring a constant and minimal sample dilution. As a result of the spiking of the samples, mixed histograms including the signal of the sample and that of the standards are obtained. However, the use of signal deconvolution approaches permits to extract the information, even in cases of signal populations overlapping. For proofing the concept, characterization of a 50 nm AuNPs suspension prepared in three different media (i.e., deionized water, 5% ethanol, and 2.5% tetramethyl ammonium hydroxide-TMAH) was carried out. Accurate results were obtained in all cases, in spite of the matrix effects detected in some media. Overall, the approach proposed offers flexibility, so it can be adapted to different situations, but it might be specially indicated for samples for which the matrix is not fully known and/or dilution is not possible/recommended.