Abstract:Micro (nano) plastics, MNPLs, have become emerging particulate human-made pollutants, and quickly become the fields of increasing concern of the public. Due to the lack of analytical technology with sufficient sensitivity and selectivity, it is difficult to fully detect and determine the characteristics of MNPLs in the environment and biological matrix. Atomic spectrometry has many advantages, such as low detection limit and high sensitivity, and shows great potential in the analysis of MNPLs. However, there is a lack of systematic summary in this field at present in order to give full play to its advantages in the analysis of plastics. In this review, the whole process of analyzing MNPLs in complex matrix based on various atomic spectroscopy techniques have been discussed, including sample labeled, treatment, purification, and detection. Furthermore, the application of atomic spectrometry in tracing the source of MNPLs in the environment, in situ identification and classification, analysis surface morphology and functional groups changes during aging process, assessments of environmental ecological risk assessment and toxicological effects were addressed aiming to improve our understanding on the environmental fate and transport of the fragments. Finally, future outlooks and research directions have been recommended based on the existing research gaps in the area.

Abstract:Vanadium (V) isotopes have shown great potential in studying planetary, geological, and environmental processes over the past decades. The accuracy and precision of V isotopic analysis are prerequisites for its application. This review first summarizes the emerging studies on the V isotope system over the past decades. Then we focus on introducing the advancements in V isotopic analysis methods using multi-colletor inductively coupled plasma mass spectrometry (MC-ICP-MS) and discuss the critical aspects to obtain high precision V isotopic data during sample digestion, chemical purification, and instrumental measurement. Significant future progress can be achieved by combining new generation of collision cell MC-ICP-MS to improve instrument sensitivity and measurement precision.

Abstract:The strontium (Sr) isotopic composition of the atmospheric particulate samples was measured using single-quadrupole inductively coupled plasma mass spectrometry. After the multivariate optimization of the main operating conditions (sample uptake rate, spray chamber temperature, and quadrupole voltages), the 87Sr/86Sr isotopic ratio was measured with an internal precision of ~0.1% (%RSD, n=12) at the Sr concentration of 2?10 μg L?1 and ~0.2% at 0.5?2 μg L?1. The isobaric interferences were mathematically fixed, whereas the instrumental mass bias was efficiently corrected by a combination of internal corrections based on the measurement of the 88Sr/86Sr ratio and bracketing external calibration. Finally, an optimized Sr isolation procedure produced a low procedural blank (0.05±0.01 μg L?1) and good recovery (78±7%) at a low Sr concentration (0.5?2 μg L?1). The applicability of the developed method was demonstrated by the analysis of a time series of PM10 samples collected from the Antarctic Plateau, which are characterized by a low Sr concentration and limited sample mass. The results were in excellent agreement with those published in the literature.

Abstract:Secondary ion mass spectroscopy (SIMS) is often the first choice to analyze precious samples because of its low sample consumption, high spatial resolution, and high sample throughput. However, samples subjected to SIMS analysis are conventionally prepared on the same mount with multiple reference materials (RMs) to monitor instrumental bias and to calibrate its accuracy. SIMS mounts prepared following this conventional protocol cannot fully satisfy requirements for analyzing different minerals containing a wealth of geological information. The limited amount of some RMs also makes it challenging to meet the demands of the increasing number of SIMS laboratories. To facilitate reuse and replacement of RMs, we tested assembling of two split-mounts into the sample holder to constitute a standard one-inch-diameter mount for further SIMS analysis. 91500 zircon, Ple?ovice zircon, Qinghu zircon, ZN3 zircon, and NIST SRM 610 glass RMs were used to evaluate the effects of differences in the electric field due to the gap between spliced parts by analyzing the U-Pb ages and oxygen isotopes on grains close to it. The results show that 206Pb/238U ages and oxygen isotopes of measured spots within a 1.5 mm distance from the spliced gap deviated from their recommended values to varying degrees. However, all spots beyond the 1.5 mm distance exhibited acceptable accuracy and reproducibility. Therefore, we propose a method that allows easy 1) reuse and 2) replacement of RMs during SIMS analysis to meet the modern analytical demands of SIMS laboratories. The proposed method will be useful, especially for the SIMS-based in situ analysis of precious samples limited in amount (e.g., lunar samples, meteorites, and others).

Abstract:MgAl2O4@MoSe2 nanocomposite was used to separate-preconcentrate bismuth ions for micro solid phase extraction (μ-SPE). FT-IR, SEM, XRD, SEM-Mapping and SEM-EDX were used to find out about the functional groups, surface morphology, surface area, elemental composition, and crystalline structure of MgAl2O4@MoSe2. Analytical parameters, such as pH, adsorbent dose, sample volume, eluent concentration and volume, vortex time, and matrix effect, were optimized to get the best recovery values. Under optimized experimental conditions and by using FAAS measurements, analytical parameters were calculated, such as the limit of detection, the limit of quantification, the preconcentration factor, the enhancement factor (EF), the relative standard deviation, the sample volume, and the eluent volume as 0.012 μg L-1, 0.04 μg L-1, 10, 8.69, 5.5, 30 mL, and 3.0 mL, respectively. The validation of the presented procedure was checked by the analysis of certified reference materials and the addition-recovery test to real samples. The presented method was applied to the determination of bismuth contents of natural water, food, and cosmetic products. Two certified reference materials (CRMs) (NCS ZC 73028 Rice and NCS ZC 73036 Green tea) were used for the validation of the presented method.

Abstract:Rapid analysis of uranium is useful for the exploration and exploitation of uranium ore, while traditional methods always require several hours for a single analysis procedure. Herein, a novel online extraction device that incorporates a heating unit was fabricated to efficiently extract the uranium from ore, followed by real-time ICP-MS detection. As a result, without sample pretreatment, the uranium content in two kinds of uranium ore can be obtained directly within 15 min with low sample consumption (1.0 mg), low energy consumption, and high recovery (90%). The present method provided a useful platform for the rapid quantitative analysis of uranium, which is beneficial for the improvement of the efficiency of exploration and exploitation of uranium.

Abstract:Foliar spay of zinc oxide nanoparticles (ZnO-NPs) is a common practice to provide the necessary Zn element for crops, which may also be a potential source for human expose to NPs with possible adverse health effects. Presently little is known about the forms and distributions of ZnO-NPs in plants after it is applied by foliar spay due to the lack of reliable quantification method. In this work, a complexed enzymatic extractant combined with single particle-ICP-MS system (SP-ICP-MS) was developed for simultaneously determining the concentrations and size distributions of ZnO-NPs in plant tissues. The measuring conditions were optimized and the method was applied to quantify ZnO-NPs uptake and distributions in rice plants after foliar application of ZnO-NPs. The results showed that the established method could well quantify the NP concentration in plant tissues with a detection limit of 16 nm; foliar spray of ZnO-NPs increased the Zn concentration (22.66 ± 0.51 mg·kg-1) in rice grains by 447%, which was still within the limits of the food safety standard of China (NY 861-2004, 50 mg·kg-1 for Zn). ZnO-NPs larger than 60 nm cannot be directly absorbed by the leaves and may instead fall into the soil. ZnO-NPs with a size between 30-60 nm in the leaves could be retained due to the hindering effect of the cellulose-hemicellulose network. The smaller ZnO-NPs with size less than 30 nm could only be detected in stems but not in the grains, indicating that ZnO-NPs were dissociated or resolved as ionic form before they were transported into grains. The xylem and phloem were believed to be the organs responsible for the translocation and transformation of ZnO-NPs after being uptake by rice leaves. The study demonstrated the feasibility of the proposed method in characterizing NP behaviours in plants and proved the effectiveness and safety of foliar application of ZnO-NPs to rice.

Abstract: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 31-35% 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.

Abstract: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 δ26Mg 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 δ26Mg 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 δ25Mg and δ26Mg of 0.00 ± 0.02‰ (2 SD, n = 106) and 0. 00 ± 0.04‰ (2 SD, n = 106), respectively.

Abstract:Analyzing the δ13C-DOC in high-salinity water remains challenging due to significant differences in interfering ions and analyte concentrations. In this study, halide interference was eliminated using an AgF solution to generate AgCl precipitate, and the δ13C-DOC was measured using a GasBench Plus preparation device coupled with isotope ratio mass spectrometry (IRMS), establishing an accurate and sensitive method to determine δ13C-DOC in high-salinity water samples. The external accuracy of the method was 0.09‰, and the difference between the measured and certified δ13C values of IAEA-601 was 0.14‰. When the carbon content of the sample was 2.0 μg (equivalent to 0.5 μg mL-1 DOC content in the sample), the precision was 0.11‰ with a 0.15‰ difference. The interference of various NaCl concentrations on the measured δ13C-DOC was evaluated, and 200 g L-1 NaCl produced an approximately -13.97‰ difference between the stable isotope result and its true value. This difference was observed when we analyzed saline samples without any measures to deal with salt interference. However, this difference was overcome using the presented procedure. The δ13C-DOC of twenty-one high-salinity water samples was determined using the proposed procedure and a total organic carbon analyzer with a high-temperature catalytic oxidation unit coupled to IRMS. The δ13C-DOC results obtained using the two methods are consistent, with differences of -0.17‰ to -0.40‰, indicating that the influence of halides is completely overcome by the proposed procedure. Therefore, the proposed method enables the analysis of the ??13C-DOC in high-salinity water regardless of the type and origin of the salt solution, provided the concentrations of DOC are between 0.5 to 50 μg mL-1, and shows great promise in allowing many labs that are currently limited to analyzing freshwaters to expand their capabilities.