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제안 방법
- However, critical comparison of these methods is difficult due to differences of steps involved, such as derivatization, clean-up, separation and detection methods with different precision and accuracy, and in the sample matrices. A preliminary experiment was carried out to evaluate efficiency of mechanical and MW extractions with two different extraction solvents using PACS-2 as a reference material. Results from isotopedilution LC-ICP/MS for all four different extraction conditions were in excellent agreement with the certified value as shown in the Table 2.
- Although a reference value is given for the PACS-2 CRM, a preliminary experiment was necessary for the test sediment to obtain approximate amount contents of DBT, which are required in exact sampling for ID analysis. Sediment samples of about 1.
- Four calibration standards were prepared by combining appropriate amounts of 1000 mg/kg Sn standard solution and the Y standard solution so that Sn/Y ratios and concentrations closely matched with those in Y-spiked DBT samples. By performing alternates measurement of peak intensity ratio of Sn/Y for four of calibration standards and four of spiked samples using a Jobin Yvon Ultima ICP/OES (Jobin Yvon, Longjumeau, Cedex, France), total Sn in DBT standard material was determined. Amounts of Sn species other than DBT were determined by LC-ICP/MS analysis of a 100 mg/kg (as Sn) methanolic solution prepared with the DBT standard material.
- 8 Another method is the used of well-characterized CRMs. In this study, the influence of degradation reactions in the sample preparation process to the DBT analysis is shown to be negligible using the PACS-2 CRM as a control sample.
- For purity analysis of DBT where excessive amount of DBT is injected into a column, for example, enough separation of DBT from the other organotin species is required. In this work, a method for purity assay of the standard dibutyltin (DBT) material was developed combining ICP/ optical emission spectrometry (OES) analysis of total Sn content and LC-ICP/MS analysis of the other organotin impurities. Optimized LC condition provided an excellent separation of all butyltin species, which made the impurity analysis of DBT standard as well as the determination of DBT in sediments feasible.
- 9. The same spike solution was also used to prepare four replicates of calibration standards at three different isotope ratios (0.85, 0.90 and 0.95) around that of the sample blends by combining appropriate portions of the solution and four independently prepared DBT standard solutions. Before and after the sediment sampling, about 0.
대상 데이터
- The CCCQM-P43 test sediment and the PACS-2 sediment reference material were provided by the National Research Council of Canada (NRCC), which is one of the pilot laboratories of the interlaboratory study. The DBT standard synthesized from enriched 117Sn for ID analysis was supplied by the other co-pilot laboratory, the Laboratory of the Government Chemist (LGC), UK, in form of methanolic solution with approximate concentration of 110 µg/g as DBTCl2. DBTCl2 with natural isotopic abundance was purchased from Sigma-Aldrich (Sheboygan, WI, USA) and used as calibration standard after purity assay.
이론/모형
- Sn species impurities in the DBT standard material were determined using the optimized LC-ICP/MS method. TBT and MBT were found as major impurities in the analysis with much less amount of an unknown compound regarded as one of the isomeric compounds of TBT.
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