A semi-discretization method based on quartic splines for solving one-space-dimensional hyperbolic equations

In this paper, based on C³ quartic splines, a semi-discretization method containing two schemes is constructed to solve one-space-dimensional linear hyperbolic equations. It is shown that both schemes are unconditionally stable and their approximation orders are of O(k⁵+h⁴) and of O(k⁷+h⁴) with k and h being step sizes in time and space, respectively, which are much higher than those of other published schemes. A numerical example is presented and the results are compared with other published numerical results.     

Development of a validated UPLC–MS/MS method for PK/PD analysis of SYL930 and its two major metabolites in dogs

A sensitive and specific UPLC‐MS/MS method was developed and validated for the simultaneous determination of 2‐amino‐2‐(2‐(4′‐(2‐propyloxazol‐4‐yl)‐[1,1′‐biphenyl]‐4‐yl)ethyl)propane‐1,3‐diol (SYL930), phosphorylated metabolite (SYL930‐P) and hydroxylated metabolite (SYL930‐M) in dog blood using SYL927 and SYL927‐P, analogues of SYL930, as the internal standards. Analytes were extracted with protein precipitation followed by chromatographic separation on a ZorbaxSB‐C₁₈ column (3.5 μm, 2.1 × 100 mm) with a gradient elution of methanol–water containing 0.1% formic acid (v /v). A triple quadrupole tandem mass spectrometer operating in the positive electrospray ionization mode was used to detect SYL930, SYL930‐P, SYL930‐M and IS transitions of 381.2 → 364.2, 461.2 → 334.2, 397.3 → 380.3, 367.1 → 350.4 and 447.5 → 320.2, respectively. The linear calibration curves for SYL930, SYL930‐P and SYL930‐M were 0.5–500, 0.2–100 and 0.5–100 ng/mL, respectively (r ² > 0.99). The intra‐day and inter‐day precisions (RSD, %) of analytes did not exceed 9.16% except for low QCs (≤16.22%), and the accuracy (RE, %) ranged from −14 to 11.4%. The mean recoveries for SYL930, SYL930‐P and SYL930‐M in dog blood were 85.13–107.94, 73.84–80.08 and 85.64–95.44%, respectively. The validated method was successfully applied to pharmacokinetic and PK/PD studies of SYL930 and its two major metabolites in dogs after an oral administration of SYL930.     

AFS-9X系列原子荧光仪软件操作功能的开发应用

介绍AFS-9X系列原子荧光仪工作系统应用管理样品校正测试样品检测结果的软件操作方法。仪器可自动显示更接近于真值的校正值及试验的回收率,加强和完善了仪器对检测结果质量控制的功能,说明了软件操作中影响检测数据准确度的注意事项。     

Adsorption of some metal complexes derived from acetyl acetone on activated carbon and purolite S-930

A new Schiff base (HL) derived from condensation of p-anisidine and acetyl acetone has been prepared and used as a chelating ligand to prepare Cr(III), Mn(II), Co(II), Ni(II) and Cu(II) complexes. The study of the nature of these complexes formed in ethanol solution following the mole ratio method (2:1, L:M) gave results which were compared successfully with these obtained from isolated solid state studies. These studies revealed that the complexes having square planner geometry of the type (ML₂), M = Co(II), Ni(II) and Cu(II), and octahedral geometry of the type [Cr^IIIL₂(H₂O)₂]Cl and [MN^IIL₂(H₂O)₂]. The adsorption studies of three complexes Cr(III), Mn(II), and Co(II) on activated carbon, H and Na-forms of purolite S-930 resin show high adsorption percentage for Cr(III) on purolite S-930 due to ion exchange interaction compared with high adsorption of neutral Mn(II), Co(II) complexes on activated charcoal. Linear plot of log Q_e versus log C_e showed that the adsorption isotherm of these three complexes on activated carbon, H and Na-forms of purolite S-930 surface obeys Freundlich isotherm and was similar to S-curve type according to Giles classification which investigates heterogeneous adsorption. The regression values indicate that the adsorption data for these complexes fitted well within the Freundlich isothermal plots for the concentration studied. The accuracy and precision of the concentration measurements of these complexes were determined by preparing standard laboratory samples, the results show relative error ranging from ±1.08 to 5.31, ±1.04 to 4.82 and ±0.28 to 3.09 and the relative standard deviation did not exceed ±6.23, ±2.77 and ±4.38% for A1, A2 and A3 complexes, respectively.     

AFS-230E双道原子荧光光度计测定蔬菜中的砷和汞

采用湿法消解蔬菜样品,用AFS-230E型双道原子荧光光度计测定蔬菜中的As、Hg重金属含量。在最佳实验条件下,As、Hg元素的工作曲线相关系数(r)分别为0.9992、0.9996,检出限分别为0.0119ug/L、0.0139ug/L,回收率分别为：91.6%~101.50%,89.8%~97.3%,相对标准偏差（RSD%,n=7）分别为1.39%、0.52%,该法可供各地测定该类蔬菜中As、Hg等重金属元素含量的参考。     

关于降低AFS-930型原子荧光光度计汞检出限的方法研究

氢化物发生-原子荧光光谱法(HG-AFS)是测试环境样品汞(Hg)的高灵敏度方法,但是为了适应污染物形态分析的需要,其灵敏度需要作进一步的提升和改善。通过提高光电倍增管负高压至280 V和空心阴极灯的灯电流至30 mA,原子化器高度设为10 mm,并降低KBH₄溶液到0.5%(KOH 0.2%)等调整措施大大改善了仪器对Hg的灵敏度,仪器检出限从原来的8 ng·L-1降至2 ng·L-1(n=6)。在优化的条件下,可以获得线性良好的0～10 ng·L-1浓度Hg标准曲线,能够实现对Hg浓度约为4 ng·L-1的水溶液的准确测定,其测试相对标准偏差<5%;选用低吸附的聚四氟乙烯器皿和优级纯以上级别试剂可将仪器的检出限降低为1 ng·L-1(n=10),使Hg的灵敏度得到进一步提升。     

Synthesis of 8-deoxypumiliotoxin 193H and 9-deoxyhomopumiliotoxin 207O

The asymmetric synthesis of 8-deoxypumiliotoxin 193H and 9-deoxyhomopumiliotoxin 207O has been achieved, starting from both enantiomers of (+)- and (?)-10. Enantiomerically pure alcohols (+)- and (?)-10 were obtained by lipase-mediated kinetic resolution of racemic 10, which was prepared in 3 steps from new lactam-type building block (?)-8 in a highly stereoselective manner.     

双道原子荧光光谱法测定蔬菜中的砷和汞

采用湿法消解蔬菜样品,用AFS-230E型双道原子荧光光度计测定蔬菜中的As和Hg重金属含量。在最佳实验条件下,As和Hg元素的工作曲线相关系数(r)分别为0.999 2和0.999 6,检出限分别为0.011 9和0.013 9μg/L,加标回收率分别为:91.6%~101.5%和89.8%~97.3%,相对标准偏差(RSD,n=7)分别为1.4%和0.52%,方法可供各地测定各类蔬菜中As和Hg等重金属元素含量作参考。