The purification of Mg requires the separation of Mg from matrix elements, which is the prerequisite for the accurate determination of Mg isotopic compositions.With the rapid development of instrumental technology, the purification process has played an important role in affecting the efficiency of isotopic measurement.This study reported a highly efficient optimized method based on the combination of precipitation process and chromatographic procedure to finish purification process within nine hours, which improved the purification efficiency.The precipitation procedure is used to remove K and optimized 2N HNO3 is proposed for collecting Mg fraction, which shortens the time in chromatographic process.With the popularization of Mg isotope analytical method and the wide application of Mg isotope in the geosciences, the existing reference materials with confirmed δ 26 Mg values are being consumed more, and there is a situation of short supply.After the verification of eleven different types of reference materials with confirmed Mg isotopic compositions using established purification process, the δ 26 Mg values of thirteen reference materials were firstly reported for broadening the selection of reference materials.In addition, the Mg concentration mismatch effect and acid molarity mismatch effect were further evaluated using Neptune Plus MC-ICP-MS in wet plasma mode.The long-term instrumental stability was assessed by repeated analysis of the in-house standard GSB-Mg, which yielded δ 25 Mg and δ 26 Mg of 0.00 ± 0.02‰ (2 SD, n = 106) and 0. 00 ± 0.04‰ (2 SD, n = 106), respectively.

The effects of several common interfering elements, low-molecular weight organic compounds (LMWOCs), and surfactants on the analytical performance of solution anode glow discharge optical emission spectrometry (SAGD-OES) were extensively studied. The resistance to interfering elements (Na, K, Mg and Ca) of different analytes (Ag, Cd and Hg) varied wildly. At extremely low concentrations of 1 mg L -1 , Ag and Cd signals were suppressed by 31-38% and 17-30%, respectively; however, even at up to 100 mg L -1 Na/K/Mg/Ca, the method exhibited satisfactory recovery rates of 91-96% for Hg measurement. These findings give references for the quantitative methods directed against different test elements. The LMW alcohols (methanol and ethanol) and carboxylic acids (formic acid, acetic acid, and propionic acid) added to solution anode exhibited complex and diverse behaviors. Signal suppression was present for Ag, while characteristic emission was enhanced in the case of Hg. Surfactants such as Triton X series gave better results in spectral pattern and analyte response, with a sensitivity increase of 1.4-3.3 times and a notable descent in background levels. Furthermore, the experimental results suggested that the Triton X-100 still improved the detection limits (DLs) and signal-to-back ratios (SBRs) of elements in samples with a certain salinity of 500 mg L -1 Na. Despite the presence of Na-rich matrix, the DLs of Ag, Cd and Hg were quite low (1.0, 0.9 and 7 μg L -1 , respectively), comparable to various microdischarge spectroscopy methods and ICP-OES.

The chemical composition of LaNi5 needed to be measured rapidly and sensitively to control the hydrogen storage capability of the material. Glow discharge mass spectrometry (GDMS) was an excellent candidate for the measurement of LaNi5 due to its high sensitivity, simple preparation, and the capabilities of simultaneous analysis of multiple elements as well as direct analysis of solids. In practice, the application of GDMS to LaNi5 analysis was constrained by the difficulties in sample preparation arising from the morphology of LaNi5 and by the lack of the matrix-matched materials. Herein, an analytical method for the determination of 25 impurity elements in ultra-pure LaNi5 particles was established using GDMS. The zirconia mortar was selected as the tool for grinding the sample into powders by comparing the hardness and the introduced contaminants to those of other mortars. Under the optimized instrumental parameters, a set of relative sensitive factors (RSF) for calibration was established using nickel matrix based certified reference material, which was the analog of the matrix-matched material of LaNi5. This assumption was validated using corresponding standards with the relative error below 30% between the measured and the certified values. The previously reported universal RSFs (X. Wei, et al. Spectrochim. Acta, Part B, 2019, 154, 43-49.) were adopted for the absent elements in the available nickel standards. With this protocol, up to 25 impurity elements in LaNi5 were quantified, and the results were further validated by the other independent methods. Our work established a rapid and sensitive GDMS method for the quantitative measurement of 25 concerned impurities in LaNi5, improving the LaNi5 material analysis contents and efficiency. This method might also be applied to the sample preparation and the generation of RSFs of target element for the other complex analytes.

Calcium carbide is an important chemical raw material, and its gas evolution volume is a crucial indicator for its quality.However, the traditional methods to determine the gas evolution volume are costly and complicated.More important, it cannot be quantitatively detected with an in-situ real-time way.Herein, a totally new method to measure the gas evolution volume of calcium carbide based on Laser-induced breakdown spectroscopy (LIBS) is proposed for the first time.Tableting and pre-pulse were used to reduce the matrix effect.Moreover, the spectral pretreatments and standardization are necessary, including the removal of abnormal spectra, fitting and correction of background baselines and optimization of characteristic spectral line.Eventually, based on the principal component analysis combined with partial least squares method (PCA-PLS), a prediction model was successfully established, with the root mean square error of prediction set (RMSEP) of 1.498 L/kg.The average relative error of prediction set (AREP) is 0.48%.Our result illustrates that the LIBS provides a new solution for the rapid, accurate, and safe determination of gas evolution volume of calcium carbide.

This review's main purpose is to provide a succinct overview of recent developments in the field of volatile organic compounds (VOCs) detection based on Laser-induced breakdown spectroscopy (LIBS).VOCs are important air pollutants, which have great harm to the environment and human body.It is of great significance to realize the rapid detection of VOCs in the atmospheric environment.LIBS is a novel atomic emission spectroscopy technology, which can achieve the rapid in-situ detection of substances and shows great potential in the online monitoring of atmospheric VOCs.To illustrate the development and difficulties of LIBS technology in atmospheric VOCs detection, some typical cases for various aspects are listed, including the detection of harmful elements in VOCs, source tracing of VOCs, the identification of isomers, and the detection of VOCs in living environment.

The miscellaneous materials, including gangue, plastic, and wood commonly present in coal.These miscellaneous materials affect the reliability of coal analysis using laser-induced breakdown spectroscopy in power plants, but have significantly distinct spectral characteristics from coal.Hence, this paper proposes a step-by-step classification method to screening the false spectra of miscellaneous materials.The first step aims to identify the plastic and wood spectra by determining the existence of specific characteristic spectral lines using the standard deviation (SD) values.The spectral lines Si 288.16 nm with the SD value of more than 850 counts and Li 670.78nm with SD value of more than 1750 counts were used as the distinguishing markers.The classification accuracy of first step was 100%.Due to the high similarity between gangue and coal, the second step utilized the random forest (RF) classification model to identify the gangue spectra.The number of trees and random variables in the RF model was optimized.The accuracy of classification model without and with the proposed step-by-step method was 98.30 and 99.96%, respectively.To assess the necessity of spectra classification, a set of calorific value analysis was performed by adding false spectra of different proportions, which were compared with analysis after removing the false spectra.The root mean square error of prediction () was 0.42 MJ kg -1 (after removing), compared with 0.50 MJ kg -1 (mixing with 10% gangue spectra), 0.56 MJ kg -1 (mixing with 20% gangue spectra) and 0.57 MJ kg -1 (mixing with 30% gangue spectra).The results demonstrated that the proposed stepby-step classification method could effectively identify the spectra of coal and miscellaneous materials and improve the accuracy of coal analysis.

In this study, a laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) method is developed for in -situ quantitative imaging of trace impurity elements in Bi4Si3O12 (BSO) crystals.This method has unique advantages of low detection limit and high spatial resolution for the analysis of defects in crystal microregions.The regression coefficients of the calibration curves for each element were greater than 0.99, and the detection limits (DLs) were 17, 5, 7, 48, 5, 7, 16, 27, and 7 ng/g for 24 Mg, 45 Sc, 48 Ti, 90 Zr, 139 La, 146 Nd, 172 Yb and 208 Pb, respectively.The LA-ICP-MS measurements were in good agreement with the results obtained using conventional ICP-MS method.Segregation phenomena of elemental impurities in the axial direction of the BSO crystal can exist during crystal growth.Finally, the distribution of the impurity elements in the dendritic crystal defect region of the crystal was visualized.We believe that this work proposes a novel less-invasive analysis method for exploring the composition-defect relationship of crystals.

Non-spectroscopic (also called matrix effects) and spectroscopic interferences (in particular, from oxide and doubly-charged ions) may compromise the accuracy of inductively coupled plasma mass spectrometry measurements.Dilution is widely used to reduce the matrix effects that depend on the absolute quantity of matrix.However, dilution is a source of errors (especially when performed manually) and takes considerable time.An alternative method of reducing the absolute quantity of matrix is proposed in this article, through a reduction in sample injection volume.In this study, capillary-based mono-segmented flow analysis (MSFA) with sample injection as small as 1 L was compared to the continuous nebulization of sample solutions and flow injection of 50-L aliquots.The injection volume and oxide interference had a positive correlation, with 1-L MSFA reducing the amount of CeO + /Ce + by up to 69%.The concurrent increase in Ba ++ /Ba + as the sample volume decreased suggests an increase in plasma temperature when smaller sample volumes are introduced.Signal suppression induced by the 400-mg L -1 Na matrix significantly decreased as the volume of the injected sample decreased and was virtually eliminated with 1-L MSFA.This decrease translated into a negative correlation between the sample volume and accuracy when a drinking water-certified reference material was analyzed by external calibration without internal standardization or matrix matching.Only 1-L MSFA yielded concentrations within the range of inclusion for all analytes.

An alternative radiocarbon sample preparation with the flame-sealed Zn/Fe reduction method by removing the reagent of TiH2 was developed, and the specifications and practices are described in detail. The graphitization parameters were optimized with 5 mg Fe powder (-325 mesh; H2-reduced spherical particles) as the catalyst, 15 mg Zn dust as the sole reductant and a reduction temperature of 500 C for 3 h, followed by 550 C for 4 h. The m-scale morphology indicated that the spherical Fe particles were coated with a mix of graphite sheets and fuzz carbon. Simultaneously, SEM-EDS, XRD and XPS verified that the graphite-Fe target consisted of mostly graphitizable semidisordered carbon and Zn-Fe crystals, with minimal amounts of ZnO and Fe3ZnC crystals, which jointly ensured good performance (high and stable ion current output and good thermal conductivity) during the AMS measurements. The average fraction modern values of the SRM OX-II (consensus value, Fm=1.3407 0.0019) and SRM IAEA-C7 (consensus value, Fm=0.4953 0.0012) samples prepared from 2017 to present were 1.3403 0.0058 (n=73) and 0.4964 0.0031 (n=18), respectively. Thus, the long-term precision of the Zn/Fe sealed tube method was better than 6 and good accuracy was achieved over several years. The average background 14 C age of inorganic material was 43392 1489 yr BP (n=44), and the ages of two 14 C-free organic materials were 45285 2016 yr BP (n=15) and 46388 2306 yr BP (n=36), indicating that low and stable carbon contamination levels were maintained throughout the entire chemical preparation process and AMS measurement over the last couple of years. The consistency between measured values and preferential values makes us confident in the preparation of various types of natural samples at normal mass size with our established vacuum line using the flame-sealed Zn/Fe reduction method.