甲基肼和偏二甲基肼水含量标准物质的定值方法研究

通过优化甲基肼(MMH)和偏二甲基肼(UDMH)的水含量气相色谱分析方法,实现对研制的MMH和UDMH水含量标准物质标称值的测定。为提高定值准确度,同时采用气相色谱标准加入法和液体水分标准物质校正法对影响水含量定值结果的因素进行研究。结果表明:气相色谱标准加入法的标准曲线线性关系良好,相关系数R~2均大于0.999;2种方法定值结果偏差较小,F检验和T检验表明2种定值方法测定结果无显著差异。该标准物质对MMH和UDMH水含量的量值传递和量值溯源具有重要意义。     

近红外光谱法快速测定萃取剂中水分含量

通过使用近红外光谱(NIR)技术,建立对萃取精馏乙醇中萃取剂水分含量的快速测定的方法。运用NIR技术结合最小偏二乘法建立萃取剂中水分含量的定量校正模型,内部交叉验证决定系数(R2)为0.993 9,内部交叉验证均方差为0.035 5。该方法操作简单,过程无污染,结果可靠,实现了萃取剂中水分含量的快速测定。     

碳酸钙水分检测方法探讨

探讨了采用卤素水分测定仪检测碳酸钙水分时升温程序和关机模式对检测结果的影响,并与采用标准方法检测的结果进行对比,从精密度、重现性方面分析了卤素水分测定仪用于检测碳酸钙水分含量的适用性。结果表明:采用卤素水分测定仪检测碳酸钙水分含量时,升温程序宜选择标准干燥升温程序,关机模式宜选择1 mg/50 s,在此参数下检测结果的相对标准偏差为3.07%,与标准方法检测的结果一致性较好,精密度高、重现性好,说明卤素水分测定仪可以用于测定碳酸钙的水分含量,且检测时间明显缩短。     

叶酸纯度标准物质的研究

通过定性分析、定量分析、均匀性检验、稳定性考察和不确定度评定,研制了叶酸纯度标准物质。其中采用质量平衡法(包括液相色谱法、水分、灰分、挥发性物质和无机元素分析)与定量核磁共振法对叶酸纯度标准物质进行了定量分析。叶酸纯品容易含有结晶水和吸附水,所以通常其主要杂质就是水分,而且叶酸受热易分解,所以难以除去水分。使用卡尔费休法和元素分析,准确测定了水分含量(8.48%)。叶酸的定值结果为90.6%,扩展不确定度为1.1%。对于实际检验中叶酸的准确测定及相关疾病的正确诊断治疗具有重要意义。     

乙酰苯胺元素含量标准物质的研制

有机元素分析仪用于测定有机化合物、煤炭等能源产品以及食品的碳、氢和氮元素含量,仪器需要有机纯物质元素含量标准物质来校准.研制了乙酰苯胺元素含量标准物质,编号为GBW06203.使用区域熔融装置提纯乙酰苯胺原料,然后分装制成标物候选物.采用气相色谱-质谱法和差示扫描量热法测定其有机杂质含量,采用卡尔·费休库仑法测量其水分...     

系列水分活度标准物质的研制

水分活度的准确测定对食品安全具有重要意义。水分活度仪急需水分活度标准物质进行校准。研制了氯化钠(NaCl)溶液和氯化锂(LiCl)溶液水分活度标准物质。采用质量平衡法和电位滴定法测定LiCl的纯度。采用重量法制备LiCl溶液,利用LiCl和水的质量以及LiCl纯度计算LiCl的质量摩尔浓度(m)。将m代入德拜-休克尔方程,计算得到渗透系数(?)。根据物理化学基本原理,由m和?计算得到水分活度的标准值。另外,还采用NaCl纯度标准物质制备了NaCl溶液水分活度标准物质,并计算出其水分活度标准值。7种标准物质的标准值分别为0.250、0.500、0.762、0.797、0.850、0.900和0.950,它们的扩展不确定度(U,k=2)不超过0.007。以德拜-休克尔方程表示的?的标准数据,由美国标准局(NBS)统计并发布。该系列水分活度标准物质可用于水分活度仪的校准和水分活度测量方法的验证。     

折光法测定MTO级甲醇中水分含量的实验研究

采用合格的MTO级甲醇为基准试剂，配置一定浓度梯度水分含量的标准样品，使用卡尔费休法测定的水分含量，使用折光仪测定的折光率建立甲醇中水分含量，折光率的标准曲线。以此方法曲线为准，研究了试样中其他组分对测定结果的影响，并对方法的准确性进行了评价。     

叶酸标准物质中杂质的分析研究

首次对叶酸杂质进行定性定量分析,采用三重四级杆液相色谱-质谱联用仪准确测定了两种杂质的含量,应用两种卡尔费休滴定法对叶酸中水分含量进行测定,并测定了微量氯离子的含量。外标法得到蝶酸和对氨基苯甲酰谷氨酸杂质的含量分别为0.687 5%、3.100%,相对标准偏差分别为2.05%、0.61%;离子色谱法测得氯离子含量为0.035%;两种方法测量水分结果分别为7.45%、7.75%。实验对于叶酸的准确测定具有重要意义,为叶酸一级标准物质的研制奠定了基础。     

有机硅密封胶基料水分测定方法

将样品溶解于含有内标物的萃取剂中,采用气相色谱法测定萃取剂的水分含量,计算出样品中的水分含量。该方法简单易操作,分析时间短。方法的精密度(RSD)≤5%,重复性(RSD)≤10%,线性R>0.99,平均回收率101%(n=6,94.1%～105.8%)。     

ICP-AES法测定赣南脐橙园土壤中有效钙和镁

本文建立了用pH=7的乙酸铵溶液作浸提剂,电感耦合等离子体发射光谱法(ICP-AES)测定赣南脐橙园土壤中有效钙和有效镁含量的方法。采用土壤标准物质(GBW07417a)验证了该方法的可靠性。用该方法快速、精准地测定了赣南脐橙果园土壤18个样品中的有效钙和有效镁的含量,为脐橙的产量提升和口感的改善能提供了积极的参考意义。     

重催油浆磺化制磺化沥青工艺条件研究

本实验用重催油浆经磺化、中和反应合成磺化沥青类产品。考察、优化了油浆磺化的原料、工艺条件,用中国石油天然气总公司钻井工程局企业标准《钻井液用磺化沥青-FT1》分析方法,对各种工艺条件下的油浆磺化产品的磺酸钠含量、油溶物、水溶物含量进行了测定比较,找到了油浆磺化制磺化沥青类产品的最佳工艺条件。     

红景天活性成分的提取工艺及其美容功效研究

利用水提法从植物红景天的根中提取活性成分,通过四因素三水平正交试验得到了较佳的提取工艺:红景天根粉碎过60目筛、料液(红景天根和去离子水)质量比1:10、提取温度100℃、提取时间10 min.提取液中的活性成分红景天苷和总黄酮的含量分别用高效液相色谱法和三氯化铝比色法测定.通过与阳性物质对照比较检验了提取液的功效,证明红景天提取液具有体外抗氧化和抑制酪氨酸酶的能力,可以作为延缓衰老和美白化妆品添加剂.     

Lipase‐catalyzed ethanolysis of soybean oil in a solvent‐free system using central composite design and response surface methodology

BACKGROUND: In this work we describe the synthesis of ethyl esters, commonly known as biodiesel, using refined soybean oil and ethanol in a solvent‐free system catalyzed by lipase from Thermomyces lanuginosus. Central composite design and response surface methodology (RSM) were employed to optimize the biodiesel synthesis parameters, which were: reaction time, temperature, substrate molar ratio, enzyme content, and added water, measured as percentage of yield conversion. RESULTS: The optimal conditions obtained were: temperature, 31.5 °C; reaction time, 7 h; substrate molar ratio, 7.5:1 ethanol:soybean oil; enzyme content, 15% (g enzyme g⁻¹ oil); added water, 4% (g water g⁻¹ oil). The experimental yield conversion obtained under these conditions was 96%, which is very close to the maximum predicted value of 94.4%. The reaction time‐course at the optimal values indicated that 5 h was necessary to obtain high yield conversions. CONCLUSION: A high yield conversion was obtained under the optimized conditions, with relative low enzyme content and short time. Comparison of predicted and experimental values showed good correspondence, implying that the empirical model derived from RSM can be used to adequately describe the relationship between the reaction parameters and the response (yield conversion) in lipase‐catalyzed biodiesel synthesis. Copyright © 2008 Society of Chemical Industry     

煤质对加压鲁奇炉运行的影响及相应对策

根据义马气化厂Mark-Ⅳ型鲁奇炉近几年的运行情况,以及实际运行过程中采集到的数据,分析了煤的灰分含量、灰熔点、粒度、发热量以及水分含量对气化运行过程的影响,并提出了相应可行的建议,对鲁奇炉的适宜原料和操作条件的选择具有一定的借鉴和指导意义。     

磷石膏生产粉刷石膏的加工工艺研究

本文在实验的基础上对磷石膏生产粉刷石膏的加工工艺进行了研究，提出了磷石膏加工工艺设计原则，优化了其配比和工艺条件。使用单掺无机矿物保水剂制备的粉刷石膏性能优于甲基纤维素保水剂，为粉刷石膏的研制提供了理论基础。     

COMPARISON OF DIFFERENT DRYING KINETICS MODELS FOR SINGLE PARTICLES

ABSTRACT

Different kinetic drying models applied to non-shrinking materials are scrutinised and compared. Rigorous mechanistic models are difficult to apply because of the large number of unknown parameters; hence simpler alternatives have been applied instead. This paper focuses on the two most commonly used kinetic models, namely; the diffusion model and the characteristic drying curves. These were compared by plotting the predicted drying curves (moisture content versus time) in the same diagram as a reference curve. The response to different changes in drying conditions and sensibility to extrapolated conditions were tested. The parameters studied were the temperature, velocity and humidity of the gas and the size and initial moisture content of the panicles. The comparison was based on two approaches; one theoretical where the reference drying curves were generated by an rigorous drying model; and one experimental where the reference drying curves were measured using a thin-layer kinetics rig. The materials under study were softwood, ceramic clay, silica gel and purolit. The results were promising in the sense that the characteristic drying curves (CDCs) and diffusion model could both predict the response to most changes in external conditions. The predictions for drying above the boiling point were however less accurate than the ones below it, probably due to internal overpressure effects.     

高岭土和硫铁矿烧渣研制聚硅酸铝铁混凝剂

用高岭土和硫铁矿烧渣作原料研制聚硅酸铝铁混凝剂（ＰＳＡＦ）,确定了生产工艺和操作条件,产品用于处理实际废水,并与传统混凝剂效果进行了比较。结果表明,ＰＳＡＦ混凝剂用药量少,处理效果好。     

COMPARISON OF DIFFERENT DRYING KINETICS MODELS FOR SINGLE PARTICLES

Different kinetic drying models applied to non-shrinking materials are scrutinised and compared. Rigorous mechanistic models are difficult to apply because of the large number of unknown parameters; hence simpler alternatives have been applied instead. This paper focuses on the two most commonly used kinetic models, namely; the diffusion model and the characteristic drying curves. These were compared by plotting the predicted drying curves (moisture content versus time) in the same diagram as a reference curve. The response to different changes in drying conditions and sensibility to extrapolated conditions were tested. The parameters studied were the temperature, velocity and humidity of the gas and the size and initial moisture content of the panicles. The comparison was based on two approaches; one theoretical where the reference drying curves were generated by an rigorous drying model; and one experimental where the reference drying curves were measured using a thin-layer kinetics rig. The materials under study were softwood, ceramic clay, silica gel and purolit. The results were promising in the sense that the characteristic drying curves (CDCs) and diffusion model could both predict the response to most changes in external conditions. The predictions for drying above the boiling point were however less accurate than the ones below it, probably due to internal overpressure effects.     

鼓风炉淤泥研制高效聚硅酸铁絮凝剂

高效无机高分子絮凝剂是目前水处理研究的热点，用鼓风炉淤泥为原料研制聚硅酸铁絮凝剂（PSF），确定了生产工艺和操作条件，产品用于处理实际废水，并与PFS的效果进行了比较，结果表明，PSF絮凝剂用药量少，处理效果好。     

静态溶液聚合法合成SA-IP-SPS型高吸水性树脂

采用氯磺酸磺化法制备了聚乙烯醇硫酸钠（SPS）,以工业级丙烯酸和SPS为原料采用静态溶液聚合法合成了具有良好吸水、吸盐水性能及较高热稳定性的聚丙烯酸（盐）-聚乙烯醇硫酸钠互穿网络型高吸水性树脂（SA-IP-SPS）,红外光谱、热重分析、硫含量分析结果表明了SA-IP-SPS互穿网络结构的形成.对SPS含量、PVA分子量的考察结果表明：PVA相对分子质量在90000～124000,SPS含量在3%左右时得到的SA-IP-SPS高吸水性树脂吸附性能最高（吸水900g·g^-1,吸0.9%食盐水97 g·g^-1）.