Mcclainmccain7239

Determination of 135Cs concentration and 135Cs/137Cs atomic ratio is of great importance in characterization of radioactive waste from decommissioning of nuclear facilities. In this work, an effective analytical method was developed for simultaneously determination of 135Cs and 137Cs in different types of waste samples (steel, zirconium alloy, reactor coolant, ion exchange filter paper and spent ion exchange resin) by coupling AMP-PAN, AG MP-1M and AG 50 W-X8 chromatographic separation with ICP-MS/MS measurement. Lenalidomide Decontamination factors of 7.0 × 106 for Co, 6.0 × 106 for Ba, 4.2 × 105 for Mo, 3.2 × 105 for Sn and 2.1 × 105 for Sb were achieved using the chemical separation procedure. The overall chemical yields of cesium were higher than 85%. A detection limit of 3.1 × 10-14 g/g for 135Cs was achieved for 0.2 g stainless steel sample or spent resin. The developed method was validated by analysis of standard reference materials (IAEA-375) and successfully applied for analysis of zirconium alloy, steel, ion exchange filter paper and spent ion exchange resin from nuclear power reactors. The obtained 135Cs can be used to evaluate the long-term environmental impact and provide useful information for waste disposal. The measured 135Cs/137Cs ratio in reactor coolant, as a characteristic information, might be useful for source identification and localization of leaked fuel element. The neutron flux of the leaked fuel element can be estimated based on the measured 135Cs/137Cs atomic ratios in the reactor coolant water. The developed method is simple and rapid (8 samples/day) for the determination of 135Cs concentrations and 135Cs/137Cs ratios in various waste samples from nuclear decommissioning.Since the rare earth elements (REEs) determination in waters is still not a routine procedure, different analytical protocols have been developed to deal with complexity and variability of sample matrices, problems caused by spectral and non-spectral interferences, insufficient instruments sensitivity, potential contamination and lack of certified reference materials. The aim of this work is to review the current measurement approaches given for REEs total concentrations in natural water samples, including surface and groundwaters as well as rain water and Antarctic ice. As inductively coupled plasma mass spectrometry (ICP-MS) has become the most widely employed technique for analysis of trace concentrations of REEs in aqueous samples it has been intended to present the common issues affecting the measurement results. Apart from a sample preparation step, various configurations of mass spectrometers and sample introduction systems, means of interferences elimination or correction, and calibration strategies used in analytical approaches for REEs analysis are discussed and compared.In this paper, a UPLC-ESI-MS was established to analyze macamide and macaene fractions from Lepidium meyenii (Maca). The antioxidant activity of Maca crude extract (MCE), total macamides (TMM) and total macaenes (TME) was evaluated by DPPH radical scavenging, ABTS radical scavenging and reducing power. The ability of MCE, TMM and TME against multiple cancer cell lines (leukemia HL-60, lung cancer A549, liver cancer SMMC-7721, breast cancer MCF-7, and colon cancer SW480) was used to evaluate their anticancer activity. The results demonstrate that TMM has the best free radical scavenging ability and reducing power compared to MCE, TME, and TMM, TME has the weakest antioxidant capacity compared to them. The difference in antioxidant properties between TMM and TME may be caused by benzylated alkamide in the chemical structure. TMM also has a good inhibitory effect on the five cancer cells. N-benzyl-(9Z, 12Z, 15Z)-octadecatrienamide (NBot) is the most cytotoxicity inhibitory of the macamides tested. The inhibitory effect of N-benzyl-9Z, 12Z-octadecadienamide (NBod) on colon cancer SW480 is near that of control group, while the inhibitory rates of NBot on leukemia HL-60, lung cancer A549, liver cancer SMMC-7721, and breast cancer MCF-7 are near those of the control group. Hence, NBot can be considered to have great potential as a natural drug with high efficiency and low side effects for cancer therapy.Here we report the peroxidase-like Au@Pt nanozyme as an integrated nanosensor for selective detection of silver ions (Ag+), where the nanozyme plays the roles as both the signal trigger and reporter simultaneously. This method relies on two critical chemical reactions, including (1) the unique inhibitory effect of Ag+ on the nanozyme triggered H2O2 decomposition at weak acid environment and (2) H2O2 induced Ag+ reduction onto the nanozyme surface at basic environment, leading to a blueshift in the localized surface plasmonic resonance wavelength (LSPR λmax) of the nanosensor. With this simple strategy, we demonstrated the sensitive and selective detection of Ag+ over a dynamic range from 0.5 to 1000 μM with a limit of detection (LOD) of 500 nM by UV-visible spectroscopy, which is below the permitted level of Ag+ in drinking water by U.S. Environmental Protection Agency (EPA). This method also exhibits satisfying recovery efficiency for Ag+ detection both in tap water and spring water from the Yuelu Mountain. With this satisfying sensing performance and excellent stability of nanoprobes, this strategy is promising for the detection of Ag+ in environment monitoring and food safety analysis.Electrophoretic stacking is developed for sensitive determination of three zwitterionic antiepileptics, namely vigabatrin, pregabalin and gabapentin, in human serum. CE separation is performed in a 25 μm fused silica capillary covalently coated with the copolymer of acrylamide with 5% content of permanently charged 3-acrylamidopropyl trimethylammonium chloride (PAMAPTAC). In background electrolyte of 500 mM acetic acid, the 5% PAMAPTAC generates an anodic electro-osmotic flow with a magnitude of (-18.6 ± 0.5) · 10-9 m2V-1s-1, which acts against the direction of the electrophoretic migration of the analytes. A sample of the antiepileptic prepared in a 25% v/v infusion solution and 75% v/v acetonitrile is injected into the capillary in a large volume attaining a zone length of up to 270 mm. After turning on the separation voltage, the antiepileptics are isotachophoretically focussed behind the zone of Na+ ions with a sensitivity enhancement factor of 78. For the clinical determination of antiepileptics, the human serum is diluted with acetonitrile in a ratio of 13 v/v and a zone with a length of 90 mm is injected into the capillary.