79SeAMS测量实验室标准中79Se/78Se比值

Using liquid scintillation counting (LSC) to determine the ratio of ⁷⁹Se/⁷⁸Se in the irradiated sample was reported. Firstly, the γ and β spectrum of irradiated sample was measured to find out the interferefering nuclide. Then, the irradiated sample was heated up to remove the interferefering nuclide from the sample as much as possible. At last, the activity ⁷⁹Se was determined by LSC, and the ratio of ⁷⁹Se/⁷⁸Se was determined to be (5.44±0.23)×10^－5. It provides reliable standard sample for AMS measurement.     

长寿命裂变产物126Sn活度和原子数的γ能谱法测定

By using HPGe γ-ray spectrometry, the activity of the long-lived fission product ¹²⁶Sn was measured. The number of ¹²⁶Sn atoms and the isotopic abundance of 126Sn/Sn were calculated based on the half-life value of 2.35×10⁵ a. The result of the isotopic abundance, (1.037±0.044)×10^－8, is consistent with the results measured by the accelerator mass spectrometry (AMS) within uncertainty limits, that confirms our procedures in the measurement of ¹²⁶Sn by AMS and lays a foundation for the AMS measurement of ¹²⁶Sn at much lower levels.     

解吸附-电喷雾离子化质谱方法快速检测啤酒中的甲基乙二醛

A desorption electrospray ionization mass spectrometry(DESI-MS) method was developed to determine methylglyoxal(MG) present in beers. This method utilized 1,2-diamino-4,5-dimethoxybenzene to convert MG to 6,7-dimethoxy-2-methylquinoxaline, and then determined the derivative by DESI-MS. 1×10^－5 mol•L^－1 MG in water and 5×10－5 mol•L^－1 MG in Yan Jing beer can be determined using this method. This time-saving method may provide a way for high-throughput analysis of MG in beverages.     

钚气溶胶直接进样ICP-MS快速分析技术-6级高效过滤器后钚气溶胶的定量

A technique for fast analysis of plutonium in airborne aerosol was developed with directly sampling ICP-MS in this laboratory. And the Pu-242 aerosol particle addition calibration method was established. The nebulized Pu-242 solution aerosol was quantitatively mixed with the airborne aerosol and then introduced into ICP-MS. The results show that the detection limit for Pu-239 concentration is down to 1.4×10^－6 Bq·L^－3. The airborne aerosol sample after through a high efficiency particulate air (HEPA) filter with six stages (efficiency per stage 99.95%) was analyzed using this technique, the plutonium concentration determined is 3×10^－4 Bq·L^－3. However plutonium could not be detected when sampling using HEPA filter at same situation, airborne aerosol also could not be detected at same situation with Condensation Particle Counter (CPC). This result shows there were some tiny plutonium particulates which passed through the six stages HEPA filter with airflow and could not be collected by the HEPA filter     

热表面电离质谱法测量钚同位素

The plutonium isotopic abundance ratio was analyzed by thermal ionization mass spectrometry (TIMS) with the ion counting technique. The ion counting system was developed and applied by our lab teem on the MAT261. It is verified with the certificated isotopic reference material. Using 3×10^－9 g of plutonium, the combined standard uncertainty of ratio of ²⁴⁰Pu to ²³⁹Pu plutonium isotopes in 3 ng is 0.070%.     

79Se-AMS生物示踪方法学的研究

由于具有放射性非常弱以及对生物组织甚至是细胞无损伤的特点，⁷⁹Se是对硒元素进行长期无损伤生命科学研究的理想示踪核素。⁷⁹Se示踪方法学的建立对于硒的生命科学与生物医学研究将具有十分特殊的意义。加速器质谱测量⁷⁹Se（⁷⁹Se-AMS）的生物示踪方法学具有高灵敏度，高准确性以及高精度等特点。通过采用⁷⁹Se-AMS方法对亚毒性剂量的硒代谢过程进行研究，建立了⁷⁹Se-AMS生物示踪方法学，重点探索了生物示踪样品的制备流程，化学处理以及样品测量过程。采用分子负离子的引出形式以及四阳极双栅电离室对⁷⁹Se和⁷⁹Br两种同量异位素进行鉴别，从而记录实际样品中⁷⁹Se的原子个数。实验建立了亚毒性剂量硒在Wistar大鼠肾脏内的代谢曲线，为生命科学以及生物医学领域提供了新的测量方法与手段，也为AMS的应用开拓了新的领域。     

电喷雾萃取电离质谱直接测定啤酒中多种氨基酸

A novel method was developed for directly detection of amino acids in beer by using extractive electrospray ionization mass spectrometry (EESI-MS) without any sample pretreatment. Taking the advantage of multiple-stage tandem MS capability of an ion trap mass analyzer, all the signals detected from beer samples were quickly identified using their characteristic fragments, resulting in confident validation of the analytical results. The average time for a single sample analysis was less than 0.5 min, and the relative standard deviations of the method were in the range of 5.0%-10.0%. The limit of determination of this method was found to be 10^－10 g•mL^－1 for most amino acids.     

简易氢化物发生-ICP-MS法测定高纯钴中痕量的砷

A method for the determination of trace arsenic in high purity cobalt with hydride generation-ICP-MS was reported. Due to the interference of the oxide complex ions ⁵⁹Co¹⁶O^＋, the background concentration of ⁷⁵As is about 100 µg•L^－1 in 1 g•L^－1 cobalt solution, which lead to the impossibility of the direct analysis for the trace As in high purity cobalt. However, the As background concentration can be decreased to several µg•L^－1 if the simple HG system was applied and the 0.05 µg•g^－1 of determination limits can obtained with this method.     

HPLC-MS/MS法测花旗松素在Beagle犬血浆中的浓度及其药代动力学研究

A rapid, sensitive and selective method for the determination of taxifolin in Beagle dog plasma was described by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Resveratrol was used as internal standard (I.S.). MS detection and quantitation were done by mass spectrometer using selected reaction monitoring at m/z 303 and 285 [M－H]^－ for taxifolin, and m/z 227 and 185 [M－H]^－ for resveratrol. The calibration curve is linear (r＞0.998) from 2 to 1 000 μg L^－1, and the lower limit of quantification(LLOQ) is 2 μg L^－1.     

多接收电感耦合等离子体质谱测定182Hf/180Hf的方法研究

¹⁸²Hf is an important radionuclide for nuclear research and supernova explosions. The reference material of ¹⁸²Hf/¹⁸⁰Hf is especially important, but not yet available. Considering the demands of nuclear science research an development, a method was developed to measure the ratio of ¹⁸²Hf/¹⁸⁰Hf with high-precision by using multi-collector inductively plasma mass spectrometry (MC-ICP-MS). The operating parameters of MC-ICP-MS were optimized. Isobar interference and mass bias were studied. The measurement result of the ratio of ¹⁸²Hf/¹⁸⁰Hf was obtained based on deducting the interference of isobaric ¹⁸²W.