Plasma Emission Spectrometry Research Articles

The Effect of heat and Storage Duration on Physicochemical Properties of Plastic Bottled Water at Sharq El Nile Locality in Khartoum State, Sudan

The physicochemical properties of plastic bottled water were studied using the Inductively Coupled Plasma Emission Spectroscopy Technique (ICPE) before and after heating and storage duration. One sample was taken from Al Byara Well - Block (39) in Sharq El Nile Locality, Sudan at fall season in 2019.This sample was exposed to sunlight in plastic bottled for (50 days) and stored for (40 days). Before heating and storage duration, various macro and micro minerals such as (Sulfur, Calcium, Potassium, Magnesium, Sodium, Copper, Silicon, Manganese, and Zinc) have been detected with different concentrations at ((0.0057, 0.170,0.003, 0.390, 0.089, 0.016, 0.085,0.0014,and 0.00057) ) respectively. The concentrations some toxic and radioactive elements including (Cadmium, Holmium, Thallium, Barium, Scandium, and Strontium) were also appeared with various concentrations at ((1.3,1.5,27,0.62,0.31,and 0.77) ) consecutively. These results may return to the location of sample, and vital activities. After heating and storage duration, concentrations of macro and micro minerals above were changed to (0.0047,0.190, 0.0026, 0.093, 0.072, 0.014,0. 067, 0.00, and 0.00) ) respectively. However, two new micro minerals which called (Iodine and Boron) was found with concentration at ((0.0095 and 0.00060) successively. Moreover, the concentrations of some toxic and radioactive elements above were modified to (1.1,0.00,24,0.65,0.23,and 0.96) ) successively, and three new toxic elements like (Mercury, Nickle, and Antimony) were existed with concentrations at ((1.1,3.7,and 6.9) ) respectively. These results may be attributed to the interaction between water and plastic and storage period. However, the results before and after heating and storage duration were discovered within background values except for (Thallium). Keywords: Inductively Coupled Plasma Emission Spectroscopy, Concentration, Sunlight, Drinking Water, Plastic Bottled.

FERROCENE DISPROPORTIONATION REACTIONS IN A PLASMA-LIQUID SYSTEM WITH A ROTATING GLIDING DISCHARGE

A plasma-liquid system with the activation of H2O distillate and 0.1 M ferrocene solution in organic solvents (ethanol, acetonitrile) with a rotating gliding discharge plasma was studied. The research was conducted using various plasma-forming gases (air, Ar, N2, CO2). Determination of plasma parameters was performed by plasma emission spectroscopy methods. It was shown that the plasma of both the rotating gliding discharge and the plasma of the secondary discharge supported by the gliding discharge are non-isothermal. The study of the physicochemical properties of the synthesis products was performed by adsorption, luminescence analysis, polarimetry, chromatographymass spectrometry and NMR methods. It was found that cyclopentadiene ligands of ferrocene disproportionate into saturated cyclic hydrocarbons (cyclopentane and pentane). Also, as a result of plasma chemical synthesis, aromatic compounds (benzene and its derivatives) are formed.

Vortex-assisted hydrophobic natural deep eutectic solvent liquid-liquid microextraction for the removal of silver ions from environmental water.

This study presents a novel approach for the quantification of silver ions in environmental water through the utilization of liquid-liquid microextraction, employing natural deep eutectic solvents in conjunction with inductively coupled plasma emission spectroscopy. The extracted solvent was characterized by Fourier transform infrared spectroscopy (FT-IR). The impact of various extractant types, extractant molar ratio, extractant volume, extraction time, and salt concentration on the efficacy of silver ion extraction was investigated. The findings indicate that the optimal extraction efficiency was attained by utilizing a 5-mL aqueous solution volume, containing 1000 μL thymol/lactic acid NADES 1:3, a salt concentration of 1 mg mL-1, a pH value of 4, and a vortex time of 4 min. Upon implementing the optimized experimental conditions, the recovery of target metal ions was from 96.9 to 101.0%. The relative standard deviations were observed to be within the range of 1.5 to 2.7%. The present study demonstrates the reproducibility, accuracy, and reliability of the method for detecting silver ions in environmental water, with linear range of 5~1000 ng mL-1 and limits of detection (LOD) and limits of quantification (LOQ) of 1.52 ng mL-1 and 5.02 ng mL-1, respectively.

Comparison of leaching behaviour of heavy metals from sediments sampled in sewer systems - environmental and public health aspect.

The article analyzes the content of heavy metals and standard physical as well as chemical pollution indicators in different types of sediments from stormwater, combined sewer and sanitary sewer systems. Nickel, lead, chromium, copper, zinc and cadmium, as well as standard physical and chemical pollution indicators, were determined in sewage sediments. Aqueous extracts of sediments samples, taken from storm water sewer inlet sediments traps, storm sewers, sanitary sewers and combined sewers, were prepared in accordance with PN-EN 12457-2:2006. After mineralization, the concentrations of the metals: nickel, lead, chromium, copper, zinc and cadmium in the extracts were determined using the inductively coupled plasma emission spectroscopy technique. The results were analyzed with a non-metric multidimensional scaling algorithm. The heavy metal content was variable depending on the sediments collection site. The heavy metals nickel, lead, chromium, copper, zinc and cadmium were found in the sediments from stormwater inlets, storm sewer and sanitary sewer channels, with variability in the concentration of individual metals. The sediments from the flushing of sanitary sewers and combined sewers did not contain cadmium. The content of heavy metals in sediments varied depending on the sampling location and type of sewer system, indicating the need for detailed monitoring to identify the sources of emissions. Sediments from stormwater sewers have higher concentrations of heavy metals, with those from sewer inlets showing zinc concentrations exceeding regulatory limits, highlighting the variability and potential environmental impact of different sewer systems.

Preparation of cerium-containing nanoporous titanium coatings for osseointegration and their promotion of osteogenic differentiation and anti-inflammatory properties

Conventional implants face many problems, such as failure to form good osseointegration and peri-implantitis in the early stage of implantation. It has been shown that hydroxyapatite (HA) has good osteoconductive ability. Also considering the potential of cerium oxide in osteogenesis and anti-inflammation, we prepared cerium-containing nanoporous HA coatings on the surface of pure titanium using the micro-arc oxidation (MAO) technique. The surface morphology of the coating was observed by scanning electron microscopy (SEM). The mechanical strength of the coating was examined by the ultrasonic oscillator. The elemental composition of the coating was examined by energy spectrum analysis (EDS). The ion release capacity of the cerium-containing coatings was examined by inductively coupled plasma emission spectrometry (ICP-OES). The hydrophilic properties of the coatings were examined by the hydrophilic angle test. In vitro, experiments were performed using rat bone marrow mesenchymal stem cells (BMSCs) and mouse mononuclear macrophages (Raw264.7). The biosafety of the cerium-containing coating was verified by live-dead staining and CCK-8 proliferation assay. The osteogenic and anti-inflammatory ability of the cerium-containing coating was examined by immunofluorescence staining and quantitative polymerase chain reaction (q-PCR). In addition, ion experiments were used to further demonstrate the osteogenic and anti-inflammatory potential of cerium ions. Subsequent animal experiments further demonstrated the osteoinductive potential of the cerium-containing HA coating. In conclusion, our cerium (HA)-containing coatings prepared by micro-arc oxidation on titanium surfaces show excellent osteogenic and anti-inflammatory properties, which are expected to improve the functionality of clinical implants and also lay the foundation for the clinical application of cerium ions.

Application of laser-induced breakdown spectroscopy for the analysis of pig bones

An application of the laser-induced breakdown spectroscopy technique (LIBS) for the elemental analysis of pig shoulder bone samples is reported. Measurements were performed using a compact laboratory-made LIBS system based on the TEA CO2 laser and time-integrated signal detection. The recorded spectra consisted of well-defined atomic and single-charged ionic lines of bone matrix elements (Ca and P) and other constituent elements (e.g. Mg, Zn, Na, K, and C) with a good signal-to-noise ratio suitable for chemical analysis. Based on the elemental composition of bone samples measured by inductively coupled plasma emission spectroscopy, limits of detection (LOD) of LIBS analysis were estimated for several elements. LOD ranged from 2.2 ppm (K) to 16 ppm (Zn). Carbon and Hα spectral lines were used for plasma diagnostics by measuring Stark widths. Optical profilometry was used to assess the capability of LIBS for depth profile analysis. For laser fluence between 13.0 and 18.2 J cm−2, the ablation rate per pulse ranged from 6 to 10 μm.

Efficient catalytic degradation of VOCs using Mn-based hydrotalcite-like compounds coupled with non-thermal plasma

Aiming to discover a novel catalyst that exhibits a high synergistic effect with plasma technology for the degradation of volatile organic compounds (VOCs), we employed manganese-based layered double hydroxides (LDHs), which are referred to as MMn-LDHs (M=Ni, Co, Fe). Comprehensive physicochemical characterization via catalyst characterization techniques such as XRD, SEM, XPS, BET, confirmed the successful synthesis of the catalysts. These analyses revealed excellent crystallinity, distinctive lamellar structure, and remarkable thermal stability for three synthesized catalysts. The experimental results demonstrate that post non-thermal plasma (post-NTP) catalytic system has significantly improved the degradation efficiency, CO2 selectivity, and carbon balance for toluene, while notably suppressing the formation of by-products (e.g., NOx and O3) compared to the NTP alone system. Among the three MMn-LDHs, NiMn-LDHs exhibited the best performance in the post-NTP-catalytic system, achieving a toluene degradation rate of 95.87%, a CO2 selectivity of 57.41%, a carbon balance of 79.86%, and an energy efficiency of 3.19 g·kWh−1 at a specific energy density (SED) of 930.45 J/L. The catalytic degradation mechanism of toluene was proposed based on a combination of catalyst characterization techniques, plasma emission spectroscopy, and gas chromatography-mass spectrometry (GC-MS). The findings revealed that plasma discharge generated a substantial amount of free radicals and active species, thereby promoting the decomposition of toluene. Subsequently, the residual toluene and intermediate products were adsorbed onto the catalysts, where they underwent further reacted with the abundant hydroxyl radicals and activate metal species on the catalyst surface, ultimately decomposing into CO2 and H2O. Additionally, the interaction of ozone with LDHs facilitated the generation of reactive oxygen species, consequently accelerating the decomposition of organic intermediates, formation of CO2, and the enhancement of toluene mineralization. The finding in this work offer valuable theoretical support for the plasma-catalytic degradation of VOCs.

Utilizing H2O2 for the selective flotation separation of chalcopyrite and galena with their surface pre-adsorbed with Isopropyl Ethyl Thiocarbamate

Chalcopyrite and galena often coexisted in ore deposits, and they are usually processed by bulk flotation and then separated to obtain valuable mixed concentrateds. In this paper, we propose a flotation reagent strategy, that uses Isopropyl Ethyl Thiocarbamate (IPETC) and hydrogen peroxide (H2O2) to achieve different floatability on chalcopyrite and galena, it is evident that chalcopyrite and galena with IPETC adsorbed on the surface can be separated by H2O2. The flotation results show that H2O2 has a great inhibition effect on galena and exhibits a weak inhibition effect on chalcopyrite. Mixture of chalcopyrite and galena with IPETC adsorbed on the surface was successfully separated by flotation with 15 mg·L-1 H2O2 at pH 7. The inhibition mechanism of H2O2 was analyzed by contact angle measurements, single-channel scanning Inductively Coupled Plasma emission spectroscopy (single-channel ICP) analysis, Fourier Transform Infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The characterization analysis indicates that the rate of H2O2 oxidation of galena is faster, resulting in more hydrophilic oxidation products such as oxides and hydroxides on the surface of galena, while the surface of chalcopyrite is less affected by H2O2. Also, compared with chalcopyrite, the adsorbed IPETC on the galena surface can be easily blanketed by oxidation products, so realizes the effective separation of chalcopyrite and galena.

Study on the Interaction Mechanism between Residual Coal and Mine Water in Goaf of Coal Mine Underground Reservoir

In this paper, the coal pillar dam body of the underground reservoir in Daliuta coal mine, along with the residual coal and the mine water present in the goaf, were taken as research subjects, and a dynamic simulation experiment device was constructed to simulate the actual process of a coal mine underground reservoir (CMUR). The composition and structure of middling coal during the experiment were determined by X-ray diffraction analysis (XRD) and X-ray fluorescence spectrometry (XRF), while changes in ion content in the mine water were assessed through ion chromatography (IC) and inductively coupled plasma emission spectrometry (ICP-OES). Based on both the composition and structure of coal as well as variations in ion concentrations in water, the interaction mechanism between coal and mine water was explored. The results showed that the water–coal interaction primarily arose from the dissolution of minerals, such as rock salt and gypsum, within coal. Additionally, coal samples in mine water exhibited adsorption and precipitation of metal ions, along with cation exchange reaction. Na+ in mine water predominantly originated from the dissolution of rock salt (sodium chloride) in coal, while Ca2+ and SO42− were released through the dissolution of gypsum and other minerals in coal. In the process of the water–coal interaction, Ca2+ in the water body was adsorbed and immobilized by the coal sample, leading to the formation and deposition of CaCO3 on the surface of the coal, thereby increasing the calcite content. These processes collectively contributed to a decrease in the concentration of Ca2+ in the water body. Moreover, the cation exchange reaction occurred between Ca2+ and Mg2+ in mine water and Na+ in the coal sample. The presence of Ca2+ and Mg2+ resulted in their displacement of Na+ within the coal matrix, consequently elevating Na+ concentration in the mine water while reducing both the Ca2+ and Mg2+ concentrations. On this basis, combined with insights from the water–rock interaction, it can be inferred that the adsorption mechanisms involving rocks played a dominant role in the decrease of Ca2+ concentration during the water–rock interactions. Meanwhile, the dissolution processes of minerals both in the water–rock and water–coal interactions predominantly contributed to the increase of Na+ and Cl− concentrations.

In vitro techniques for evaluating smear layer removal by root canal irrigants: a literature review

Introduction: The purpose of this review is to address the most commonly used techniques for evaluating smear layer removal ability or chelating capacity of root canal irrigants, including Energy Dispersive X-Ray Spectroscopy (EDS or EDX), Atomic Absorption Flame Spectrometry (AASF), wavelength dispersive X-ray fluorescence spectrometry (WDXRF), inductive coupled plasma emission spectroscopy (ICP-AES), Scanning Electron Microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FTIR). Methods: An electronic literature search was conducted in the Pub Med / MEDLINE database of indexed journals from 1992 to 2020. The search terms included chelating, chelation, calcium chelation, smear layer, smear layer removal, and demineralizing effect. Results: All the techniques were classified in terms of their results, both quantitatively and qualitatively. Even though smear layer removal and chelating capacity are not the same parameters, most of the studies included both techniques to correlate their results. SEM is the most commonly used technique for evaluating smear layer removal using various root canal irrigants. Ethylenediaminetetraacetic acid (EDTA) (17%) was the most widely studied root canal irrigant. Conclusion: Different techniques can be used to evaluate smear layer removal and chelating capacity of root canal irrigants. All of these methods have their corresponding advantages and disadvantages. This study aimed to provide researchers with a background for the selection of technique(s) to study the irrigant´s capacity for calcium chelation, which is applicable to smear layer removal.

The discrimination of geographical origin of lotus root from major producing areas of China based on multi-elemental analysis combined with multivariate data analysis

Lotus root is a popular traditional Chinese food of great economic and nutritional significance, which has different qualities, characteristics, and commercial value from various regions due to the climate and growing environment. Therefore, it is essential and urgent to establish an accurate and effective method to trace the geographical origins of lotus roots. This study combined mineral element analysis and multivariate statistical analysis to discriminate the origins of 147 lotus root samples from different production regions of China. The concentrations of 15 elements were determined by inductively coupled plasma emission spectrometry and inductively coupled plasma mass spectrometry. In addition, chemometric techniques, including ANOVA, principal component analysis and stepwise linear discriminant analysis were utilized to identify the geographical origin of lotus roots. The results showed that the levels of the 15 elements were significantly different by ANOVA. The study indicates that stepwise linear discriminant analysis yielded an average discrimination rate of 99.3%.

Synthesis, characteristics, adsorption and catalytic behavior of NiO‐ZnO‐ CdO/reduced graphene oxide Nanocomposites

AbstractThe nanocomposites NiO‐ZnO‐CdO/reduced graphene oxide (N‐Z‐C/rGO) were prepared using the reflux method. These nanocomposites were characterized using various techniques, including infrared spectroscopy (FTIR), Raman spectroscopy, scanning electron microscopy (SEM), electron dispersive spectroscopy (EDS), induced coupled plasma emission spectroscopy (ICP), and X‐ray diffraction (XRD). The application of the synthesized nanocomposites was investigated in two fields: the removal of azo dyes and the oxidation of certain organic compounds. To explore the use of this compound as an adsorbent, the removal of methylene blue (MB) and rhodamine B (RhB) dyes was studied. Under optimal conditions, the adsorbent absorbed MB with 98 % efficiency in 15 minutes and RhB with 96 % efficiency in 30 minutes. In the second part of the study, the performance of the nanocomposite in the oxidation of benzyl alcohol and styrene was examined. Optimal conditions for oxidizing benzyl alcohol used tert‐butyl hydroperoxide(TBHP) and acetonitrile, achieving 83 % efficiency and 92 % selectivity for benzoic acid in 6 hours. α‐methyl styrene oxidation used chloroform and TBHP, reaching 97 % efficiency and 90 % selectivity for acetophenone in 4 hours.

Investigation and characterization of black crusts on limestone at historical buildings in the cities of İstanbul and Edirne (Turkey)

The formation of black crust upon building stones and the resulting damage depend upon the fabric of the stone and atmospheric effects. The formation of black crust on limestone occurs more rapidly and distinctly compared to stones such as granite and sandstone, in which the mineral calcite is absent or in small quantities in its composition. In this study, black crust formation developed on the surfaces of limestone in İstanbul and Edirne, where important historical monuments belonging to the Byzantine and Ottoman Empires are located, were examined visually, microscopically, and experimentally. The factors causing the development of this crust and their effects on weathering were determined, and comparative analyses of the black crust with the sub-layer stone were made. In addition, by classifying the morphology, chemical structure, mineralogical composition, and damage to the stone by the black crust, chemical, and physical weathering that causes surface deterioration on the stone and back of the crust were examined. Physical (Schmidt hammer), mineralogical (X-ray diffraction), petrographic (polarizing microscopy), chemical (inductively coupled plasma-emission spectrometry, inductively coupled plasma-mass spectrometry, Fourier transform infrared spectrometry), and microstructural (field emission scanning electron microscopy with energy dispersive X-ray spectrometry) analyses were carried out to characterize this process. The black crust formation on limestone was shown to be caused by sulfation.

Changes in Physicochemical Properties of Coal and Their Mechanism Due to Supercritical CO2–H2O Treatment

The dissolution of supercritical carbon dioxide (ScCO2) in water forms a ScCO2–H2O system, which exerts a transformative influence on the physicochemical characteristics of coal and significantly impacts the CO2-driven enhanced coalbed methane (CO2-ECBM) recovery process. Herein, the effect of ScCO2–H2O treatment on the physicochemical properties of coal was simulated in a high-pressure reactor. The migration of major elements, change in the pore structure, and change in the CH4 adsorption capacity of coal after the ScCO2–H2O treatment were detected using plasma emission spectroscopy, the low-temperature liquid nitrogen adsorption method, and the CH4 adsorption method, respectively. The results show that (1) the ScCO2–H2O treatment led to mineral reactions causing a significant migration of constant elements in the coal. The migration of Ca ions was the most significant, with an increase in their concentration in treated water from 0 to 16–970 mg·L−1, followed by Na, Mg, and K. Al migrated the least, from 0 to 0.004–2.555 mg·L−1. (2) The ScCO2–H2O treatment increased the pore volume and pore-specific surface area (SSA) of the coal via the dissolution and precipitation of minerals in the coal pores. The total pore volume increased from 0.000795–0.011543 to 0.001274–0.014644 cm3·g−1, and the total pore SSA increased from 0.084–3.332 to 0.400–6.061 m2·g−1. (3) Changes in the CH4 adsorption capacity were affected by the combined effects of a mineral reaction and pore structure change. The dissolved precipitates of the minerals in the coal pores after the ScCO2–H2O treatment caused elemental migration, which not only decreased the mineral content in the coal pores but also increased the total pore volume and total pore SSA, thus improving the CH4 adsorption capacity of the coal. This study provides theoretical support for CO2 sequestration and ECBM recovery.

A Novel Composite Hydrogel Material for Sodium Removal and Potassium Provision.

Sodium ions are commonly found in natural water sources, and their high concentrations can potentially lead to adverse effects on both the water sources and soil quality. In this study, we successfully synthesized potassium polyacrylate (KMAA) hydrogel through free radical polymerization and evaluated its capability to remove sodium ions from and supply potassium ions to aqueous solutions. To assess its performance, inductively coupled plasma emission spectroscopy (ICP) was employed to analyze the sodium ion removal capacity and potassium ion exchange capability of the KMAA hydrogel at various initial sodium ion concentrations and pH values. The results demonstrated that the KMAA hydrogel exhibited remarkable efficiency in removing sodium ions and providing potassium ions. At pH 7, the maximum adsorption capacity for sodium ions was measured at 70.7 mg·g-1. The Langmuir model, with a correlation coefficient of 0.98, was found to be more suitable for describing the adsorption process of sodium ions. Moreover, at pH 4, the maximum exchange capacity for potassium ions reached 243.7 mg·g-1. The Freundlich model, with a correlation coefficient of 0.99, was deemed more appropriate for characterizing the ion exchange behavior of potassium ions. In conclusion, the successfully synthesized KMAA hydrogel demonstrates superior performance in removing sodium ions and supplying potassium ions, providing valuable insights for addressing high sodium ion concentrations in water sources and facilitating potassium fertilizer supply.

A real-time monitoring of pre-overcharge in high‑nickel lithium ion batteries via plasma emission spectroscopy

Using the calibration-free atomic spectroscopic technique on lithium (Li) I with its wavelengths at 610.35, 610.65, and 670.79 nm, Li ion signals at varying state of charge (SOC) from high‑nickel (>88 %) batteries with NCA (Ni-Co-Al) cathode and SCN (silicon carbon nanocomposite) anode are detected in real-time (<3 s). The laser-induced plasma spectroscopy (LIPS) revealed that moderate changes in the concentrations of Li and metals (Ni, Co, and Al) during the normal charging underwent an abrupt concentration change in Li as the SOC reached above 75 %. Verified by using SEM-EDS (Scanning Electron Microscopy-Energy Dispersive Spectrometer), this sudden decrease of Li ions in cathode is deemed as being indicative of the state of overcharge. The present work is aimed at developing a new opto-chemical SOC sensor while the experimental set up offers a new method for detecting the state of pre-overcharge in nickel-rich Li-ion batteries.

Fast degradation of carbamazepine in water by electric discharge plasma

The proliferation of pharmaceuticals in the aqueous environment has adversely impact on human health and ecosystem balance. Pharmaceutical contaminations are difficult to remove effectively by conventional treatment technologies. In order to degrade carbamazepine (CBZ) efficiently, a common antiepileptic drug, three plasma discharge modes were studied, including liquid-phase discharge, air gas-liquid jet and dielectric barrier discharge. It is noteworthy that the degradation efficiency and energy yield reached to highest levels (0.11 g/kWh) when operating at 225 W input power under liquid phase discharge, compared with the other discharge modes. The parameters of concentration, electrode distance, volume, input power and frequency of the discharge were also evaluated and optimized. Plasma emission spectroscopy revealed the degradation process is mainly attributed to reactive oxygen species (ROS), while the role of reactive nitrogen species was not significant. The contributions of diverse ROS were assessed by radical quenching experiments, including p-benzoquinone, p-phthalic acid and tert-butanol. The possible degradation intermediates and pathways of CBZ were tested and analyzed by liquid chromatography-mass spectrometry (LC-MS). Comprehensively consideration of cleanliness, degradation efficiency and application difficulty, liquid-phase discharge treatment is a promising technology for water treatment.

A Co‐Ni‐CM Heterogeneous Catalyst for the Direct Synthesis of Amides from the Oxidative Coupling of Aldehydes with N‐Substituted Formamides

AbstractGiven the importance of amides in pharmaceutical and chemical industries, a Co−Ni composites (Co−Ni‐CM) heterogeneous catalytic system for the synthesis of amides from the oxidative coupling of aldehydes with N‐substituted formamides has been developed under mild conditions. The catalyst was prepared by pyrolysis under ambient atmosphere using Co‐BTC supported NiCl2 as a precursor. The catalytic system possesses good catalytic ability and good compatibility with functional groups. The surface morphology and internal element composition of the catalyst were characterized by powder X‐ray diffraction (XRD), BET adsorption, high resolution transmission electron microscope (HRTEM), scanning electron microscope (SEM), inductively coupled plasma emission spectroscopy (ICP‐OES) and X‐ray photoelectron spectroscopy (XPS). The results show that the interaction of Co−Ni is a key factor for the good catalytic activity of the catalyst. Then control experiments related to the mechanism of this transformation indicate a free radical process is involved in this transformation. More importantly, the catalyst has an excellent recycling performance and can be recycled seven times without obvious loss of catalytic activity.

Progress Toward Machine Learning Methodologies for Laser-Induced Breakdown Spectroscopy With an Emphasis on Soil Analysis

Optical emission spectroscopy of laser-produced plasmas, commonly known as laser-induced breakdown spectroscopy (LIBS), is an emerging analytical tool for rapid soil analysis. However, specific challenges with LIBS exist, such as matrix effects and quantification issues, which require further study in the application of LIBS, particularly for the analysis of heterogeneous samples, such as soils. Advancements in the applications of machine learning (ML) methods can address some of these issues, advancing the potential for LIBS in soil analysis. This article aims to review the progress of LIBS application combined with ML methods, focusing on methodological approaches used in reducing matrix effect, feature selection, quantification analysis, soil classification, and self-absorption. The performance of various adopted ML approaches is discussed, including their shortcomings and advantages, to provide researchers with a clear picture of the current status of ML applications in LIBS for improving its analytical capability. The challenges and prospects of LIBS development in soil analysis are proposed, offering a path toward future research. This review article emphasizes ML tools for LIBS soil analysis, which are broadly relevant for other LIBS applications.

A comparative study of the mineral elements in different medicinal plant parts of Daphne altaica Pall.

Daphne altaica Pall. is an important plant in traditional Chinese medicine. Mineral elements play an important role in the formation of active ingredients in medicinal plants. In this study, 14 mineral elements were quantitatively determined by inductively coupled plasma emission spectrometry using the roots, stems and leaves of D. altaica. The distribution variance of mineral elements between different organs were analyzed by statistical analysis methods such as single factor analysis of variance (ANOVA), correlation analysis (CA), principal component analysis (PCA) and cluster heat map. The results show that the mineral element contents in corresponding parts of D. altaica exhibited significant variation, with the order from highest to lowest being K > Ca > Mg > Fe > Al > Mn > Na > Zn > Sr > Cr > Ni > Cu > Pb > Mo. Among them, the highest content of mineral elements are K, Ca, Mg, Mn, Cu and Mo in leaves, and the stems contains more Zn, Sr, Cr and Ni, while the content of mineral elements Fe, Al, Na and Pb in roots is much higher than the other two organs. The ANOVA revealed significant variations in the mineral element content across different regions of D. altaica (p < 0.05). Based on single factor analysis of variance, different parts of D. altaica had different fingerprint of mineral elements, and the concentration of the same mineral elements in different parts had significant difference (p < 0.05). The principal component analysis (PCA) model showed that the cumulative variance contribution rate of first two principal components was 99.10%, in which Mn, Mg and Ca have higher load values, which is consistent with the results of bi-plot and cluster analysis. These results indicated that there were great differences in absorption and utilization of mineral nutrient elements between roots, stems and leaves of D. altaica, and there was significant correlation among mineral elements, indicating that there was a complex synergistic and antagonistic effect among the elements. At the same time, the discriminant analysis of the characteristic elements provided a scientific basis for the quality control of D. altaica.