胶束增敏荧光光度法测定加替沙星含量

提出了测定加替沙星的胶束增敏荧光光度法,并对影响加替沙星荧光性质的各种因素进行了研究。加替沙星浓度在2×10^-6～1．8×10^-5mol／L范围内与荧光强度呈良好的线性关系,检出限为65．64μg／L。加标回收率为90％-105％。该方法简便,快速,可直接用于药物制剂中加替沙星含量的测定。     

人血凝块DNA三种提取方法的比较

采用高盐法、硅珠法、改进的经典酚抽提法三种方法提取人血凝块DNA,通过紫外分光光度仪及琼脂糖凝胶电泳测定DNA的纯度和含量.实验结果表明,硅珠法提取时间快,所提取的DNA含量高;经典酚抽提法操作过程简单,但用有机溶剂提取,污染比较严重;高盐法提取要用大量的血凝块,且提取的DNA含量很不稳定.因此,硅珠法是提取人血凝块DNA的一种比较好的方法.     

高强高模PVA纤维原液可纺性研究

影响高强高模聚乙烯醇（PVA）纤维原液可纺性的关键因素有PVA的醋酸根含量及聚合度;纺丝原液中的PVA浓度及溶解程度、添加剂及硼酸加入量,纺丝过程中喷丝头的电位及电化学腐蚀;凝固浴中钙镁离子含量等。本文在多年生产过程中研究了上述控制参数对原液可纺性的影响,并提出了防范措施。比如在PVA中残存醋酸根含量≤0．05％、聚合度1850＋50、PVA浓度15．8％时可纺性较好,同时也对PVA的浸泡时间、浸泡温度、纺丝过程中喷丝头的处理等提出了指导建议。没有发现聚乙烯醇的其它指标与高强高模PVA纤维原液的可纺性有直接的关系。     

The evaluation of selected poly(vinyl acetate) and acrylic adhesives: A final research update

Abstract

The final report on the Canadian Conservation Institute's poly(vinyl acetate) and acrylic adhesive research is given after 25–27 years of dark aging and 12–15 years of light aging. A total of 27 poly(vinyl acetate) and 25 acrylic adhesives were tested for pH, volatile emissions (mostly acetic acid), flexibility, strength, and yellowing after aging. In 1996, the work was first published after three to five years of aging data had accumulated. Measurements for pH, yellowing, strength, and flexibility were recently repeated again and these results are reported here. These new data points are reported to provide insight into the effect of these longer aging periods on the products included in the study. As well, the most stable (according to set criteria) poly(vinyl acetate) and acrylic adhesives tested are revealed, which, except for a few products, do not differ greatly from those reported in 1996.     

乙酸乙酯制备实验的改进

从实验装置和催化剂两个方面,对师专有机化学实验中乙酸乙酯的制备进行改进,重点研究以冰乙酸和95%乙醇为原料,一水合硫酸氢钠为催化剂,制备乙酸乙酯。实验结果表明,酯化的优化条件为乙酸:乙醇:一水合硫酸氢钠的摩尔比为1:1.65:0.072,反应时间30min,产率达64.1%。     

碱石灰对甲烷制备实验影响的探讨

甲烷的制取实验,是学习有机化学,认识有机化合物性质和了解有机反应特点的一个重要实验。常用无水醋酸钠与碱石灰共热来制取。但要达到最佳实验效果却有许多值得探讨的内容。本文从碱石灰的角度探讨其对甲烷制备的影响。     

液相色谱法同时检测食品中的苯甲酸、山梨酸、糖精钠

采用气相色谱仪及液相色谱仪．用液相色谱法同时检测食品中的苯甲酸、山梨酸、糖精钠．特别是对固体食品及高蛋白、高油脂食品的测定,目的是拓宽检测食品的范围,优化实验条件,从样品的前处理,检测仪器的选择,超标时的判断等几个方面,论证了该方法的适用性及可靠性．     

酯化分光光度法间接测定乙酰氯

以乙酸乙酯、盐酸羟胺和氯化铁的反应体系为基础,用酯化分光光度法间接测定了乙酰氯。实验结果表明,当酸度为0．18 mol／L,c(Fe3 )与c(H2NOH)比值等于5．5及c(H2NOH)与c(CH3COOC2H5)比值大于100时,乙酸乙酯的线性范围为4．6～28．2μg/mL,相关系数(r)0．9991,检出限2．3μg/mL。本方法用于乙酰氯工业品的测定,RSD=2．9％(n=6),加标回收率为97％-99％。     

微波辐射硫酸氢钠催化合成肉桂酸苄酯的研究

采用微波辐射技术,以内桂酸和苄醇为原料,在硫酸氢钠(NaHSO4·5H2O)催化下合成了肉桂酸苄酯.最佳反应条件微波辐射功率为464W,辐射时间为4 min,醇酸摩尔比为111,催化剂用量为0.2 g,酯化率为97%.     

Oxidizing Cellulose to 2,3-Dialdehyde Cellulose by Sodium Periodate

Study on oxidizing cellulose to 2.3-dialdehyde cellulose by sodium periodate （NalO4） was carried out. The effects of reaction conditions such as pH of solution, temperature, oxidant concentration, oxidation time. the particle size of 2,3-dialdehyde cellulose and alkali treatment temperature on the dialdehyde concentration ot cellulose were investigated in detail, The results show that the aldehyde group content was created while reaction temperature and alkali treatment temperature increased. The most principal factors affecting the aldehyde group content of 2,3-dialdehyde cellulose were found out and the best oxidation conditions were as follows： the pH was 2. the reaction temperature was 45℃. the mass ratio of cellulose to NalO4 was 1/2, the reaction time was 4 h, the alkali treatment temperature was 70℃ and smaller particle size was 0.80 mm.