2021, 42(4):166-174. DOI: 10.46770/AS.2021.106
Abstract:Trace elements play important roles in many physiological processes. The disorder in the metabolism and/or homeostasis of the trace elements will cause pathogenic changes, and finally lead to the development of diseases. This present work aimed to investigate the effect of anticancer metallodrug cisplatin on the homeostasis of trace metal elements, iron (Fe), zinc (Zn) and copper (Cu), in both human HEK293 normal cells and A549 lung cancer cells by using inductively coupled plasma mass spectrometry (ICP-MS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The levels of trace metal elements in both whole cells and nuclei subjected to cisplatin treatment were measured by ICP-MS, and results showed that accompanying with the increasing concentration of cisplatin, the content of Fe inside whole cells and nuclei of both normal and cancer cells increased, implying that cisplatin may induce ferroptosis, contributing to its anticancer activity. While the level of Cu and Zn in the whole cells increased with increase in cisplatin concentration, the level of Cu and Zn, in particular the latter, in nuclei decreased with increase of cisplatin concentration. These implicate that cisplatin may compete with Zn for binding to metalloproteins in nuclei, leading to efflux of Zn from nucleus. The normalized signal intensity of Fe, Zn, and Cu in single cells detected by ToF-SIMS increased accompanying with increased cisplatin concentration, being in line with that obtained by quantitative ICP-MS on large quantity of cells. These findings provide novel insights into better understanding in the mechanism of action of cisplatin.
2021, 42(4):175-182. DOI: 10.46770/AS.2021.023
Abstract:In this work, the characteristic emission lines of Cu, Au, Ag, Al, Ni, and Pd are obtained in a Q-switched Nd: YAG laser-induced plasma. Furthermore, the signal enhancement is carried out separately by making use of the continuous-wave (CW) CO_2 laser as well as the spark discharge. The former enhances the signal intensity via plasma heating according to the inverse Bremsstrahlung (IB) mechanism, whereas the latter relies on plasma reheating and subsequent lifetime elongation. As a consequence, both methods lead to the temperature rise of the plasma. In addition, the corresponding electron density of the plasma is notably elevated in spark-assisted LIBS (SA-LIBS). It is also shown that the enhancement of the ionic lines is much higher in SA-LIBS against the other one. Although the CW-CO_2 laser benefits an electrodeless arrangement, SA-LIBS is considered to be a better candidate due to its facile and low-cost setup.
2021, 42(4):183-189. DOI: 10.46770/AS.2021.070
Abstract:In this work, the depth profile analysis capability with direct current glow discharge mass spectrometry (dc-GD-MS) was evaluated by examining molybdenum disulfide (MoS2) films on Al and steel substrates. The optimized glow discharge conditions for obtaining an ideal flat crater and an efficient signal intensity were a discharge current of 1.0–1.5 mA and a discharge pressure of 4.7 mPa. The dc-GD-MS depth profile analysis provided depth resolutions of 0.55 μm for the MoS2/Al sample and 0.70 μm for the MoS2/Steel sample. The interface of 4.46 μm for MoS2/Al and 4.55 μm for MoS2/Steel determined by dc-GD-MS was close to the thicknesses of 4.85 μm and 5.45 μm, respectively, as measured by field emission scanning electron microscopy (FE-SEM). A high-carbon steel standard sample (NIST SRM 1264a) was used to validate the reliability and accuracy of the method. Relative errors of less than 12% were obtained compared with the certified concentration and the relative standard deviation (RSD, n = 20) of typical elements within 10%. The dc-GD-MS depth profile analysis provided an efficient and reliable approach for the depth analysis of the MoS2 film.
2021, 42(4):190-196. DOI: 10.46770/AS.2021.071
Abstract:A rapid and simple co-precipitation method for iodine separation from natural samples was developed for determination of 129I using accelerator mass spectrometry (AMS). The method includes three steps, i.e. decomposition of organic iodine, iodine separation and target preparation using co-precipitation, and sensitive measurement of 129I/127I ratio using AMS. The recovery of iodine was higher than 90% for most natural water samples in the decomposition step using K2S2O8. Iodine in the digested sample was then co-precipitated as AgI-AgCl-Ag2SO3-Ag2SO4 with a typical recovery of 95-98%. It was observed that addition of 0.2 mg 127I carrier can significantly improve the measurement uncertainty of low-level 129I samples by enhancing iodine ion current. The overall recovery of iodine in the entire procedure was higher than 80%, and a detection limit of 1.0×105 atoms (or 2.2×10-17 g) for 129I was achieved. The developed method was validated by certified reference material (IAEA-418) and five types of natural water samples in comparison with results using the conventional solvent extraction method. Analytical results showed good agreement with the reference values for all samples, confirming the reliability of the developed method. The simple operation, with no need for organic solvent and small amount of iodine carrier addition make the developed method suitable for rapid and reliable determination of low level 129I in natural water samples.
2021, 42(4):197-202. DOI: 10.46770/AS.2021.026
Abstract:A highly sensitive analytical technique was developed in which gaseous hydrogen selenide generated by sodium tetrahydroborate reduction was transported and trapped on a resistively heated platinum-coated W-coil trap for in situ preconcentration. The selenium concentration was determined using hydride generation-atomic absorption spectrometry (HG-AAS). The surface of the W-coil was covered with platinum using the electrodeposition technique in the presence of H2 and Ar. According to the results of Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy (SEM-EDX) images, the ratio of Pt was 54.74% on the W-coil trap surface. Various experimental conditions, such NaBH4 and hydrochloric acid concentration, and carrier gas flow rate, were optimized. In addition, the effect of the hydride-forming elements was quantitatively evaluated. The limit of detection for Se was 21.1 ng/L. The proposed method was also applied to the determination of selenium in certified reference material (SRM 1640a Trace Elements in Natural Water) which showed that the analysis could be performed with a relative error of about 8%. The precision of the method was evaluated and a relative standard deviation (%RSD) lower than 10% was obtained.
2021, 42(4):203-209. DOI: 10.46770/AS.2021.128
Abstract:Damaged coins can be identified effectively via spectral analysis based on LIBS, which is of great significance for coin recycling. This paper takes the Renminbi (RMB), the Chinese currency, as the example, including the denominations of YI FEN, ER FEN, WU FEN, YI JIAO, WU JIAO and YI YUAN. Some characteristic lines of Mg, Al, Fe, Cr, Cu, Sn, Ni, Na and Ca were observed in the spectra, as well as the molecular bands of AlO. Principal component analysis (PCA) was used to reduce the dimension of the spectra of the different RMB coins. The samples after dimension reduction are classified by k-Nearest Neighbors (KNN), and 4 categories were obtained with a classification accuracy of 100%. Further, new spectra of different denomination RMB coins were added to the original data for the same analysis. The results are in good agreement which shows the potential of the combination of LIBS, PCA and KNN for the analysis and identification of different coins.
2021, 42(4):210-216. DOI: 10.46770/AS.2021.068
Abstract:Analysis of the elemental abundance and distribution in biological tissues by laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) adds to clarifying the basic questions of metabolic research and enables bioaccumulation and bioavailability studies in ecological and toxicological risk assessment. In this work, a method based on matrix-matched gelatin calibration LA-ICP-MS for the determination of essential and toxic elements in biological samples was developed. By using a mold-prepared procedure, the elemental inhomogeneity distributions in the synthesized gelatin gels were improved, which was verified by using the 3D (surface- and depth-mapping) LA-ICP-MS protocols. The limits of detection (LODs) ranged from 0.014 μg g?1 (Ba) to 48 μg g?1 (K). The results of the analysis of biological reference materials (RMs) were in good agreement with the certified values. Furthermore, a reliable bio-mapping LA-ICP-MS method is proposed for studying the metabolism of heavy metals in rat liver injected with CdS/PbS quantum dots. Our results show that the high concentration of Pb and Cd co-exist (positive correlation as high as 78%) in hepatocytes and sinusoids, which indicates that the PbS/CdS quantum dots are not dissociated into toxic heavy metal ions (i.e., Pb2+, Cd2+) in the metabolic process of the liver.
2021, 42(4):217-226. DOI: 10.46770/AS.2021.027
Abstract:A novel magnetic Ce(III) ion-imprinted polymer (Ce(III)-MIIP), grafted on organic-inorganic hybrid monolithic vinyl functionalized Fe3O4 (Fe3O4@HM), was synthesized for the first time by using the surface ion imprinting technology, in which Ce(III) was used as the template ion and acrylamide as the functional monomer. After the synthesized nanocomposites were well characterized, some parameters such as pH, adsorption time, eluent type, elution time and eluent volume, which affects the efficiency of magnetic solid phase extraction (MSPE), were studied in the determination of Ce(III). Under the optimized experimental conditions, Ce(III)-MIIP nanoparticles were used as the MSPE matrix, followed by inductively coupled plasma mass spectrometry (ICP-MS) determination with excellent selectivity, strong anti-interference ability, low mass transfer resistance and high adsorption capacity. The limit of detection, enrichment factor and adsorption capacity were 0.008 μg·L?1, 25 and 67.8 mg·g?1, respectively. The protocol was validated by analyzing certified reference materials and spike recoveries of complex environmental and mineral samples with satisfactory results. The relative standard deviations for the real samples were 1.7%~7.0%. In view of the advantages of facile preparation, fast adsorption rate, excellent selectivity and high adsorption capacity to Ce(III), the hybrid monolith-assisted Ce(III)-MIIP-based MSPE-ICP-MS protocol is promising for the determination of cerium in real environmental and mineral samples.