含喹诺酮类多残留鳗糜自然基体标准样品快速制备

建立了含5项喹诺酮类多残留鳗糜自然基体标准样品(RM)制备方法。通过鳗鲡药浴并控制药浴液初始浓度与定时捕捞、均质、辐照灭菌、均检稳检、协同定值等过程,制备了预期目标含量水平的含氟甲喹、噁喹酸、氧氟沙星、诺氟沙星、环丙沙星等喹诺酮类多残留鳗糜自然基体标准样品。     

含毒死蜱残留茶叶的自然基体标准样品研制

为获得与真实检测样品完全一致的含毒死蜱残留茶叶自然基体标准样品,建立了其制备方法。以每亩约31.2 g毒死蜱用药量对茶树喷洒0.22 g/L毒死蜱药液,监控检测施药后茶叶中毒死蜱含量,适时采茶,正常制茶,磨粉过网筛获得含毒死蜱残留茶粉样。经均匀性检验、稳定性检验、协同定值和不确定度评估,制得检测质量控制用含毒死蜱残留茶叶自然基体标准样品。     

含氟甲喹残留的鳗鲡肉糜自然基体标准样品的制备

为了获得与实际检测样品完全一致的检测质量控制样品,研制了含氟甲喹的自然基体鳗鲡肉糜标准样品。在模拟人工养殖的自然条件下适量施用氟甲喹药物,采集符合预期水平(氟甲喹含量为5～10 μg/kg)的阳性材料。取带皮的阳性肌肉均质,过10目筛网。样品用尼龙/聚丙烯(PA/CPP)耐蒸煮复合膜袋包装,经Co60-γ射线12 kGy剂量的辐照灭菌;经均匀性检验、稳定性检验、中国合格评定国家认可委员会认可实验室液相色谱-串联质谱法检测协同定值。所建立的制备方法为含药物残留的鳗鲡肉糜的自然基体标准样品的实验室制备提供了一种选择。     

鸡肉中尼卡巴嗪残留基体标准样品的研制

为填补我国尼卡巴嗪药物残留基体标准样品的空白,建立了鸡肉中尼卡巴嗪残留基体标准样品的研制方法。通过在饲料中添加尼卡巴嗪药粉喂养白羽肉鸡,使药物在鸡体内自然代谢,得到尼卡巴嗪残留阳性动物。取鸡前胸肉制成肉糜,经均质、冷冻干燥、粉碎、筛分、包装、辐照灭菌等处理,制备了355份含有尼卡巴嗪残留的鸡肉冻干粉。按照国家标准样品的规范,进行了均匀性检验、稳定性检验、定值和不确定度分析。采用液相色谱-串联质谱法(LC-MS/MS)测定样品中的尼卡巴嗪含量,以8家具有资质的实验室进行协同定值。结果表明本批标准样品的均匀性和稳定性良好,在-70、4、25、50℃下能稳定保存14天,在-18℃下保存的稳定性可达12个月,符合国家标准样品的相关要求。最终确定标准样品中尼卡巴嗪的标准值为(157.7±11.0)μg·kg^-1(k=2)。该标准样品可用于尼卡巴嗪的检测方法优化、检测实验室的能力评价,对于食品中尼卡巴嗪残留检测具有重要意义。     

吡虫啉标准样品的研制

采用重结晶法,以工业品为原料制备吡虫啉标准样品,利用高效液相色谱法测定其纯度并作为均匀性检验方法和定值方法,制得的标准样品均匀性、稳定性检验合格。该标准样品的标准值为(99.47±0.085)%。     

双相不锈钢等六种不锈钢光谱分析校正用标准样品的研制

研制了6种光谱分析校正用的不锈钢标准样品,包括五种奥氏体不锈钢和一种双相不锈钢.此6种不锈钢的化学成分设计参照以下牌号的钢种:0Cr18Ni9、00Cr19Ni10、0Cr17Ni12Mo2、00Cr17Ni14Mo2、0Cr18Ni10Ti及00Cr23Ni5Mo3N.在冶炼、浇铸、轧制及锻造等操作中采取了多种工艺措施,保证了材料的规格和均匀性.由国内5家具有资质的分析实验室参与协作定值.定值元素包括不锈钢样品中的主要合金元素及部分杂质元素总共迭18项(C,Si,Mn,P,S,Cr,Ni,Cu,Mo,V,Co,Ti,Sn,As,W,Al,Nb,N等).分析数据的统计处理采用数据统计软件,并按国内外相关标准的规定进行,文中给出了上述18项元素的标准值及其不确定度.此6种标准样品的有效期定为10年.     

甲醇中溴苯标准样品的研制

介绍甲醇中溴苯标准样品的研制方法.标准样品采用称量法制备,气相色谱-质谱法进行均匀性和稳定性检验,以配制值为标准值,并对其不确定度进行分析评定.结果表明,甲醇中溴苯标准样品的均匀性良好,至少在24个月内是稳定的,可用于环境监测分析.     

高炉生铁化学分析用与光谱分析用国家标准样品的研制

在冶炼、铸造、加工等操作中采取多种工艺措施,研制了高炉生铁化学分析用与光谱分析用国家标准样品,对研制的标准样品进行严格的均匀性和稳定性检验.由国内8家具有资质的分析实验室参与协作定值.定值元素达19项(C,Si,Mn,P,S,Cr,Ni,Cu,Mo,V,Ti,Co,Als,Alt,As,Sb,Sn,Pb,Zn等).分析...     

含磷元素铸造铝合金光谱分析标准样品的研制

介绍含磷元素铸造铝合金光谱分析标准样品的制备工艺、数据处理及定值结果。采用分步调整化学成分法调整标准样品中化学成分的含量,用极差法进行均匀性检验,多家实验室协同定值。研制出的标准样品经过生产试用分析,达到设计指标,可满足分析含磷元素铸造铝合金中磷的需要。     

土壤中有机氯农药残留分析用标准样品的制备

介绍了土壤中有机氯农药残留分析用标准样品的制备方法。土壤样品经风干、研磨、筛分、混匀后装瓶。样品经索氏提取、弗罗里硅土小柱净化后,采用气相色谱-质谱法对残留的有机氯农药进行测定。结果表明,采自沈阳地区的土壤中的有机氯农药含量分布较为均匀,是一种理想的环境标准样品候选物样品。该研究为土壤中有机氯农药残留分析用标准样品的研制奠定了基础。     

Immobilization of (dd)heteronuclear hexacyanoferrates(II) in a gelatin matrix

The data concerning a possibility of the synthesis (dd)heteronuclear hexacyanoferrates(II) with (M¹)^II and (M²)^II ions (M¹, M² = Mn, Co, Ni, Cu, Zn, or Cd) due to the contact of M¹ ₂[Fe(CN)₆] immobilized in the gelatin matrix with aqueous solutions of M²Cl₂ chlorides, were systematized and generalized. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 8–17, January, 2008.     

Graft copolymers of natural rubber and poly(dimethyl(acryloyloxymethyl)phosphonate) (NR-g-PDMAMP) or poly(dimethyl(methacryloyloxyethyl)phosphonate) (NR-g-PDMMEP) from photopolymerization in latex medium

Graft copolymers of natural rubber and poly(dimethyl(acryloyloxymethyl)phosphonate) (NR-g-PDMAMP), and natural rubber and poly(dimethyl(methacryloyloxyethyl)phosphonate) (NR-g-PDMMEP), were prepared in latex medium via a “grafting from” methodology based on the photopolymerization of dimethyl(acryloyloxymethyl)phosphonate (DMAMP) and dimethyl(methacryloyloxyethyl) phosphonate (DMMEP), respectively, used as phosphorus-containing monomers. The grafting polymerization was initiated from N,N-diethyldithiocarbamate groups previously bound in side position of the rubber chains. The effects of monomer concentration on monomer conversion and grafting rate were investigated, showing that conversion and grafting rate increased with increasing monomer concentration and reaction time. Highest conversions and grafting rates were obtained with a molar ratio [DMAMP]/[initiating units] = 7 for a reaction time of 180 min. Calculation of the graft average length () from ¹H NMR spectra of the synthesized graft copolymers showed values were in the range of 9-73. Visualizations of NR-g-PDMAMP and NR-g-PDMMEP latices by Transmission Electron Microscopy (TEM) showed that they exhibit core-shell morphologies. Degradation of NR-g-PDMAMP and NR-g-PDMMEP occurred in two steps: decomposition of dimethylphosphonate-functionalized grafts took place prior to the second step corresponding to the decomposition of NR backbone, but the degradation temperature of this last step was higher than that of pure NR.     

Determination of combustion energies and the standard enthalpies of formation for the complexes of RE(Et_2dtc)_3(phen)

Solid complexes, RE(Et2dtc)3(phen) (RE=La, Pr, Nd, Sm-Lu), were synthesized with sodium diethyldithiocarbamate (NaEt2dtc3H2O),1,10-phenanthroline (o-phen·H2O) and hydrated lanthanide chlorides in absolute ethanol. The constant-volume combustion energies of complexes,ΔcU, were determined by a precise rotating-bomb calorimeter at 298.15 K. The standard enthalpies of combustion,ΔcHmθ, and standard enthalpies of formation,ΔfHmθ, were calculated for these complexes, respectively. The experiment results showed the "tripartite effect" of rare earth.     

Co-pyrolysis of olive residue with poly(vinyl chloride) using thermogravimetric analysis

Pyrolytic process has a promising potential for the environmentally friendly upgrading of lignocellulosic materials and plastic waste. The co-pyrolysis of olive residue and poly(vinyl chloride) was investigated under nitrogen atmosphere by dynamic thermogravimetric analysis in the temperature range of 300–975 K. Two main stages of mass loss have been evidenced by TG analysis. The first occurs in the temperature range of 420–684 K, and the second occurs at 631–840 K. This research was focused on the interaction between olive residue and poly(vinyl chloride) during the pyrolysis process. Discrepancies between the experimental and calculated TG/DTG profiles were considered as a measurement of the extent of interactions occurring on co-pyrolysis. It was found that reactivity of olive residue was increased in olive residue/PVC mixture. In addition, a kinetic analysis was performed to fit thermogravimetric data, the mixture is considered as multistage process. A reasonable fit to the experimental data was obtained for all materials and their mixture by isoconversional Friedman method.     

H-point standard addition method for simultaneous determination of Fe(II), Co(II) and Cu(II) in micellar media with simultaneous addition of three analytes

H-point standard addition method, HPSAM, with simultaneous addition of three analytes is proposed for the resolution of ternary mixtures. It is a modification of the previously described H-point standard addition method that permits the resolution of three species from a unique calibration set by making the simultaneous addition of the three analytes. The method calculates the analyte concentration from spectral data at two wavelengths where the two species selected as interferents present the same absorbance relationship. These wavelength pairs are easily found, and can be selected to give the most precise results. Diethyldithiocarbomate (DDC) in a cationic micellar solution of cetyltrimethylammonium bromide (CTAB) was used for determination of Fe(II), Co(II) and Cu(II) at pH 5.50. The results showed that simultaneous determination of Fe(II), Co(II) and Cu(II) could be preformed in the range of 0.0–6.0, 0.0–8.0 and 0.0–12.0 μg ml⁻¹, respectively. The proposed method was successfully applied to the simultaneous determination of Fe(II), Co(II) and Cu(II) in several synthetic mixtures containing different concentration of Fe(II), Co(II) and Cu(II).     

Recent topics in application of selective Rh(II)-catalyzed CH functionalization toward natural product synthesis

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Yb(III)-daunomycin interactions. Determination of Nature and number of species by matrix rank analysis

The nature and number of species in Yb(III)-daunomycin solutions have been investigated by graphical and computational methods both of which are based on matrix rank analyses. Determination of the rank of an absorbance matrix, which is the largest non-zero determinant of the matrix, permits the determination of the number of species in solution. The multiple regression analyses performed on the Yb(III)-daunomycin system enabled the determination of the nature of a species that exists at different metal to ligand ratios: ML₂ at ratios less than 1.5, M₂L at ratios greater than 15, and probably predominantly ML in between the two ratios. The matrix rank analyses approach is suited, it was found, to bracket the range of concentration ratios where a particular species predominates. While this is true by and large, it appears that the adequacy of the methods depends on the degree of complexity of the system.     

Simultaneous determination of Fe(II) and Fe(III) by kinetic spectrophotometric H-point standard addition method

The H-point standard addition method (HPSAM) for simultaneous determination of Fe(II) and Fe(III) is described. The method is based on the difference in the rate of complex formation of iron in two different oxidation states with Gallic acid (GA) at pH 5. Fe(II) and Fe(III) can be determined in the range of 0.02–4.50 μg ml⁻¹ and 0.05–5.00 μg ml⁻¹, respectively, with satisfactory accuracy and precision in the presence of other metal ions, which rapidly form complexes with GA under working conditions. The proposed method was successfully applied for simultaneous determination of Fe(II) and Fe(III) in several environmental and synthetic samples with different concentration ratios of Fe(II) and Fe(III).     

基于定量指纹图谱技术的中药质量控制

定量指纹图谱技术是中药指纹图谱技术与多指标成分定量分析相结合的中药质量控制模式。定量指纹图谱技术的发展包括定量组分的制备、过程控制的指纹图谱技术和产品含量测定3个主要部分。本文以丹参为例,通过水提、醇沉、过膜、大孔树脂分离和工业色谱分离5个工艺流程制备了丹参定量组分,对各个工艺步骤以指纹图谱技术考察其稳定性和重复性。对丹参定量组分中的原儿茶醛、迷迭香酸、丹酚酸B 3个成分进行含量测定。3个成分的含量总和大于50%。定量组分的制备以现有的活性成分为目标,经过去粗存精的工艺过程,其质量标准得到了有效的提高。