羊毛的化学改性及其阳离子染料染色性能研究

合成了一种阴离子型羊毛改性剂,测定了羊毛纤维经改性剂处理后的白度、碱溶解度、断裂强度及伸长率等性能,讨论了改性羊毛对阳离子染料上染率的影响因素,测定了改性羊毛染色后的皂洗牢度和磨擦牢度。实验结果表明,羊毛经阴离子改性剂处理后机械性能基本不变,在100℃、pH=5、染色60 m in后阳离子染料的上染率达到80%以上,并且具有较高的染色牢度。     

Determination of antimony in sediments and soils by slurry sampling graphite furnace atomic absorption spectrometry using a permanent chemical modifier

For comparison of action of mixed permanent modifiers Ir/Nb and Ir/W, the influence of the amounts of modifier components was studied and the atomic absorption pyrolysis and atomization curves were determined with different modifiers. The optimum amounts of modifier components were 30 μg Ir and 40 μg of Nb that were deposited onto the L'vov platform in advance to analytical measurements. The long-term performance of the Ir and Nb permanent modifiers was derived from the investigations by scanning electron microscopy and energy dispersive X-ray spectrometry. The soil and sediment slurries were prepared in 4% hydrofluoric acid and 6% suspension of polytetrafluoroethylene in order to remove the high concentration of silica during the pyrolysis step of 900 °C. The calibration was made by using aqueous standards. The analysis of certified reference materials confirmed the accuracy and reliability of the proposed analytical approach. The precision of Sb determination was characterized with less than 6% RSD.     

Comparison of ethylammonium formate to methanol as a mobile-phase modifier for reversed-phase liquid chromatography

Ethylammonium formate (EAF), (C2H5NH3+HCO2-), is a room-temperature ionic liquid that has a polarity similar to that of methanol (MeOH) or acetonitrile. The separation at 1 mL/min of a test mixture of vitamins or phenols on a polystyrene-divinylbenzene column using either an EAF- or MeOH-water mobile phase is similar in terms of both resolution and analysis time. Because the viscosity of EAF is higher than that of MeOH, the plate count for phenol at room temperature is lower by about a factor of 1.1-1.4 depending on the flow rate. However, van Deemter plots show that this loss in plate count at 1 mL/min can be recovered and improved from 1500 to 2400 plates by working at a slightly elevated temperature of 55 degrees C. A slower flow rate such as 0.8 mL/min can also substantially improve the plate count as compared to 1-1.5 mL/min. Log P (octanol partition coefficient) versus log k' data for a variety of neutral test solutes are again similar whether EAF or MeOH is used as the organic modifier. Resolution of certain peak pairs such as 2,4-dinitrophenol/2,4,6-trinitrophenol and p-aminobenzoate/benzoate is enhanced using EAF as compared to MeOH. One advantage of EAF is that control of retention of solutes such as water-soluble vitamins under totally aqueous mobile phase conditions is environmentally preferable for quality control applications. In addition, EAF seems to be a milder mobile-phase modifier than MeOH for certain proteins such as lysozyme.     

Metabolomic Analysis of The Chemical Diversity of South Africa Leaf Litter Fungal Species Using an Epigenetic Culture-Based Approach

Microbial natural products are an invaluable resource for the biotechnological industry. Genome mining studies have highlighted the huge biosynthetic potential of fungi, which is underexploited by standard fermentation conditions. Epigenetic effectors and/or cultivation-based approaches have successfully been applied to activate cryptic biosynthetic pathways in order to produce the chemical diversity suggested in available fungal genomes. The addition of Suberoylanilide Hydroxamic Acid to fermentation processes was evaluated to assess its effect on the metabolomic diversity of a taxonomically diverse fungal population. Here, metabolomic methodologies were implemented to identify changes in secondary metabolite profiles to determine the best fermentation conditions. The results confirmed previously described effects of the epigenetic modifier on the metabolism of a population of 232 wide diverse South Africa fungal strains cultured in different fermentation media where the induction of differential metabolites was observed. Furthermore, one solid-state fermentation (BRFT medium), two classic successful liquid fermentation media (LSFM and YES) and two new liquid media formulations (MCKX and SMK-II) were compared to identify the most productive conditions for the different populations of taxonomic subgroups.     

XR类多药耐药调节剂的定量构效关系研究

运用启发式(HM)方法建立了40个XR类化合物的结构与calcein-AM分析中的活性的线性模型,模型预测得到的判定系数R2=0.882 7.用径向基函数神经网络(RBFNN)方法建立了非线性模型,模型预测得到的判定系数R2=0.927 6.对2种方法所得的结果进行比较,RBFNN模型的预测结果更为精确,因此更适合用来建立定量构效关系研究模型.     

Influence of the solvation process on solute adsorption in reversed phase liquid chromatography

The adsorption isotherms of phenol were acquired by frontal analysis on six different reversed phase adsorbents from five different organic solvent solutions. The end-capped octadecyl columns only differed in the bonding density of the C(18) ligands. The inverse method was used to confirm the estimated isotherm parameters derived from the frontal experiments. The effect of the bonding density of the end-capped octadecyl bonded phase on the adsorption properties of phenol from different mobile phase compositions was investigated. The adsorption behavior of phenol has changed from Langmuir type to BET type with the change of the organic modifier and the bonding density of the adsorbent.     

石墨炉原子吸收法测定生物样品中的铊

为建立测定生物样品中铊的石墨炉原子吸收法,通过微波消解,采用基本改进剂,改变石墨炉灰化温度等操作条件,提高了该法的准确度和精密度.结果表明,方法的线性范围为0～100 μg/L;检出限:血为0.10 mg/L;尿为0.02 mg/L;头发为0.20 mg/kg;回收率:血为83.1%～108%;尿为89.6%～105%...     

Ammonium Acetate Extracts and Their Analysis for the Speciation of Metal Ions in Soils and Sediments

Abstract

The use of ammonium acetate (1 mol/l at pH 7) extraction of soils and sediments for the speciation of metal ions is briefly discussed. Because the sensitivity of flame atomic absorption spectrometry (FAAS) is insufficiently sensitive for the determination of many of the heavy metals in ammonium acetate extracts of unpolluted, and even in some polluted soils, the use of electrothermal atomic absorption spectrometry (ETAAS) was studied. A general procedure, using graphite furnace atomisation and the “universal” matrix modifier, palladium, was developed, that was sufficiently sensitive for the determination of Cd, Cr, Cu, Ni, Pb and Zn even in unpolluted soils. The concentration of zinc, however, will almost always be high enough for determination of FAAS and this method is to be preferred to ETAAS for this element.

While, for Cr, Cu, Ni and Pb, direct calibration with external standard solutions is practicable, it is necessary to use the standard additions calibration method for cadmium, to avoid matrix interference effects. The standard additions technique is recommended, however, because it compensates for real differences in the operating parameters of different instruments set to the same nominal values. This is particularly important for interlaboratory comparisons or for certification analyses in the preparation of reference materials.