食品考核盲样中锰元素的测定

分别采用微波消解法和湿法消解法消解,用火焰原子吸收光谱仪测定盲样中锰元素含量,对比了不同消解方法对测定结果的影响,并作了方法准确度和精密度考察,微波消解的加标回收率在87. 0%～97. 5%之间,RSD1. 11%～1. 33%(n=5),湿法消解的加标回收率在98. 0%～109. 0%之间,RSD 0. 51%～1. 25%(n=5),两种消解法测定结果差异无统计学意义(P0. 05),上报考核盲样结果分别为1. 18 mg/L和1. 22 mg/L,评价为满意。为保证测定结果的准确性,重点把握样品前处理和质量控制等关键点。     

酶联免疫法对食用油中黄曲霉毒素B_1的检测

目的:建立一种对食用油中黄曲霉毒素B_1(Aflatoxin B1,AFB_1)的检测方法。方法:食用油样本经60%甲醇-水提取,再做1︰5稀释,通过酶联免疫吸附法(enzyme linked immunosorbent assay,ELISA)测定样本中AFB1。结果:阴性样品中AFB1的回收率分别为:92.5%、84.8%及86.3%;方法检出限为1μg/kg,与液相方法检测结果的相对标准偏差小于10%。结论:酶联免疫法对食用油中AFB1的测定结果与液相法比较符合率高,能够用于食用油中AFB1的快速、准确检测。     

常用杀菌剂生物测定中稀释母液的配制方法

介绍了杀菌剂生物测定中常用杀菌剂稀释母液的配制方法。对于杀菌剂原油及易溶于环己酮的固体原药可配制成1%的水乳剂或微乳剂母液,溶剂用量为0～2.5%,加入1%的正丁醇增加体系的稳定性,表面活性剂选用1602#和AEO–6(质量比3﹕1),质量分数2%。易溶于水的原药可配制成1%水剂,加入1%的1602#,以增加湿润展布性能。对于选择溶剂困难的固体原药可配制成1%水悬浮剂母液,其中润湿分散剂为2%1602#和1%农乳500#,粘度调节剂为0.2%黄原胶。上述母液体系组成简单,减少了有机溶剂、表面活性剂等对毒力测定结果的干扰,便于提高生物测定结果的可靠性和可比性。     

通脉降脂咀嚼片质量标准提高

[目的]对原有通脉降脂咀嚼片质量标准进行提高。[方法]采用HPLC法测定处方中三七的三七皂苷R1、人参皂苷Rg1、人参皂苷Rb1的含量。[结果]三七皂苷R1、人参皂苷Rg1、人参皂苷Rb1进样量分别在0.238~2.380μg、0.788~7.880μg、0.542~5.420μg范围内线性关系良好,平均回收率分别为:100.68%、100.06%、99.57%,RSD分别为0.38%、0.50%、0.69%,(n=9)。[结论]本方法结果准确,重现性良好,可用于通脉降脂咀嚼片的药品质量控制。     

燃烧法测定丁腈橡胶中结合丙烯腈含量

采用燃烧法,通过元素分析仪测定了丁腈橡胶( NBR) 中结合丙烯腈含量,考察了试样制备条件及试样质量对测定结果的影响,分析了方法的精密度,并与凯氏定氮法测定结果进行了对比。结果表明,试样制备的适宜抽提时间和干燥时间分别为1. 0,2. 0 h,试样质量宜为2 mg; 该方法的相对标准偏差为 0. 24% ～ 0. 53%,精密度较好; 对于结合丙烯腈质量分数为20% ～ 40%的NBR,燃烧法测定结果与凯氏定氮法无显著性差异,稍高于凯氏定氮法,两者差值为1. 13% ～ 1. 64%,且测定时间缩短至15 min 左右。     

气相色谱法速测油菜中的乙烯释放量

采用毛细管柱气相色谱法测定了油菜盛花期的乙烯释放量,以外标法峰高定量,乙烯测定结果相对偏差(RSD)为1.10%,Napus SW0742油菜经质量分数为1.4%的化杀灵WP1处理后,乙烯释放量为1.47 μL·g-1·h-1,对照材料的为0.06 μL·g-1·h-1,结果反映了育性转换中乙烯释放量的明显变化.测定方法简便、快速、灵敏度高、结果理想.     

红外光谱法测定丁苯橡胶中聚合苯乙烯含量

应用红外光谱法测定丁苯橡胶中聚合苯乙烯的含量。分别选择700cm-1以及967和990cm-1处作为苯乙烯和丁二烯单元的定量峰位,通过建立标准曲线,测定丁苯橡胶中聚合苯乙烯含量。试验结果表明,本方法测定的相对标准偏差为1.5%～2.2%,测定结果与核磁共振法测定结果的相对误差在3.3%以内。     

活性炭富集-电感耦合等离子体发射光谱法测定精矿中金的含量

实验详细考察研究了活性炭富集-电感耦合等离子体发射光谱测定金精矿中金的含量。实验主要研究了称样量、焙烧方式、盐酸浓度对活性炭吸附的影响及电感耦合等离子体发射光谱谱线的选择。该方法测量的范围为1.00～200μg·g^-1,检出限为0.037μg·g^-1,测定的结果的相对标准偏差为0.93%～2.50%,测定的结果的相对误差为0.32%～0.72%,加入标准物质的回收率为94.40%～105.20%。本方法与国家标准测定结果吻合良好。具有精密度好,准确度高,结果令人满意,能够满足生产需求。     

腐霉利的气相色谱分析

探讨了腐霉利的气相色谱分析方法 ,采用氢焰离子化检测器 ,5% OV- 1 0 1 Chromosorb G.AWDMCS填充的 1 .0 m× 3mm i.d玻璃柱 ,柱温 2 50℃ ,检测室和汽化室温度 2 70℃ ,以邻苯二甲酸二辛酯为内标物。实验结果为 :回收率在 1 0 0 .0 %～ 1 0 3.6% ,变异系数≤ 0 .1 1 %。     

苹果酯的合成工艺

以乙酰乙酸乙酯和乙二醇为原料 ,经缩合及精馏合成了苹果酯。缩合反应在 60℃ ,乙酰乙酸乙酯与乙二醇物质的量比为 1∶1 .3 ,有机酸催化剂用量为原料质量的 1 %的条件下反应 6～ 7h ,获得了最佳反应结果 ,反应总收率 75.4 % ,纯度 98%。     

煤的溶胀处理对药用腐植酸提取的影响研究

以气煤、肥煤、焦煤、瘦煤为样煤,进行了样煤的粉碎、有机溶剂溶胀和硝酸氧化处理,考察了处理后煤样中的药用腐植酸得率。结果表明,吡啶和N,N-二甲基吡咯烷酮是溶胀较好的溶剂;样煤粉碎后,随着粒度的减小,煤的溶胀率增加;粒度粉碎至200目的气、肥煤经吡啶溶胀和硝酸氧化后,煤样的药用腐植酸得率可达到73.0%和71.4%,而经甲醇溶胀和硝酸氧化的200目气煤药用腐植酸得率为56.4%和58.4%。实验结果表明,煤样经过溶胀和硝酸氧化处理,对药用腐植酸的提取有促进作用。     

组合裂纹漏磁检测有限元分析

用有限元法分析了组合裂纹漏磁场,得到了裂纹缺陷漏磁场空间分布,给出了裂纹深度与裂纹漏磁场磁感应强度之间的关系曲线。通过实验得到了与有限元分析结果一致的结论。     

Anaerobic degradation: the effect of the combined treatment of substrates on the refractory fraction

The anaerobic digestion of landfill leachates mixed with domestic sewage was studied using a batch reactor at laboratory scale. Batch assays were carried out with different proportions of leachate in the feed: 100, 70, 50 and 30% by volume, with and without adjustment of pH, in order to determine the percentage of acidification and methanization, COD removal, anaerobic biodegradability and biomass growth yield. The main effect of the mixing with sewage was a synergistic improvement of the anaerobic treatment of leachates, but in different ways; the greatest improvement in COD removal was obtained when the proportion of leachate in the feed was 70%, but the highest degree of anaerobic biodegradability was obtained with 30% of leachate in the feed. The kinetics of these assays was studied and the experimental data were fitted to a modification of the equation of Chen and Hashimoto. A new concept of ‘non‐biodegradable fraction’ is proposed. © 2002 Society of Chemical Industry     

双波长薄层扫描法测定扶正抗癌丸中黄芪甲苷含量

应用双波长薄层扫描法测定扶正抗癌丸中黄芪甲苷含量 ,平均回收率 96 .9% ,RSD为 1.72 %。结果 :方法重现性良好 ,结果准确可靠。     

Improvement of the photostability of isotactic polypropylene by the incorporation of ethylene

The effect of the incorporation of ethylene on the photostability of isotactic poly(propylene) (iPP) was studied with the aim of improving the photostability. iPP was prepared with a random ethylene sequence (ethylene–propylene random copolymer, rPP), and the photooxidative degradation behavior was compared with that of homogeneous iPP. Both samples were thermally post‐treated under vacuum to ensure the same crystallinity. The degradation behavior was studied by infrared spectroscopy (IR), gel permeation chromatography (GPC), and temperature rising elution fractionation (TREF) measurements. The rates of hydroperoxide and carbonyl formation in the irradiated iPP increased with irradiation time for > 192 h, whereas those in the irradiated rPP are almost constant after 96 h. The change in molecular weight with the irradiation time showed similar behavior, suggesting that the degradation reaction in the irradiated rPP was suppressed after 96 h. The degradation behavior of rPP was thought to be due to the dissociation of the methyl group, which leads to the termination of degradation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1863–1867, 2002     

依伐卡托中间体的合成工艺改进

改进了依伐卡托(Ivacaftor)中间体2,4-二叔丁基-5-硝基苯基乙基碳酸酯的合成工艺。原料2,4-二叔丁基苯酚经过氯甲酸乙酯保护酚羟基、硝化得到中间体和2,4-二叔丁基-6-硝基苯基乙基碳酸酯的混合物,不经柱层析纯化直接利用石油醚重结晶,以56.1%的总收率制得高纯度的中间体,经HPLC测定中间体的纯度为95.4%。改进后的工艺操作简单、成本低廉、易于工业化放大,为依伐卡托中间体的合成提供了一种新的、高效的制备方法。     

排尘结构对导叶式旋风管内流动分布影响的数值研究

通过数值模拟的方法研究了排尘结构对装有分流型芯管导向叶片式旋风管内流场的影响规律。研究发现,随排尘口直径增加,环形空间切向速度增加,分离空间内旋流区切向速度增加,外旋流区切向速度减小,经分流型芯管侧缝流量减小;旋风管压降随排尘口直径增加而减小,排尘口直径为200mm和250mm时,旋风管能耗最低;锥体尺寸增加可有效减小灰斗区及外旋流区的能耗。     

氢氧化钠催化多聚甲醛与苯酚缩聚工艺对树脂性能的影响

采用氢氧化钠催化多聚甲醛与苯酚合成酚醛树脂。在氢氧化钠用量、水量恒定和加成工艺条件不变情况下,研究了缩聚温度、缩聚时间对产品黏度、固含量、拉伸强度及可发性的影响,并用红外光谱对产品进行表征。结果表明:与缩聚温度相比,产品的黏度对缩聚时间敏感;与缩聚时间相比,产品的固含量对缩聚温度敏感,产品的拉伸强度对缩聚温度敏感;产品黏度和固含量综合影响泡沫的质量;红外光谱表明产品的分子结构含有酚醛树脂的特征官能团。     

合肥市金寨路高架桥交通噪声分布规律研究

通过对合肥市金寨路高架复合道路进行交通噪声监测,研究高架复合道路交通噪声的分布规律。结果表明：噪声与车流量密切相关,随着与高架路距离的增大,地面各测点的噪声值呈递减趋势;高架复合道路平直段与下坡路段的噪声在临街建筑竖直立面的分布规律基本一致。     

A study of the effect of surface pre-treatment on the adhesion of coatings

This paper deals with the study of effects of mechanical surface preparation on the adhesion of coating with high content of zinc dust. Five kinds of mechanically blasted surfaces were studied. The following were used as abrasives: steel shot, steel grit, brown corundum oxide and zirblast. The last surface type was modified by MBX Blaster technology (mechanical bristle blasting). The surfaces topography was quantified by a roughness profilometer. The shape and size of the incurred inequalities on the modified surfaces were studied using 3D microscope images of the surface. The purity of the surfaces after pre-treatment was evaluated by impurity glued on the tape and measuring the reflection of light from the surface. Fractal analysis was used to evaluate the diversity of inequalities on the prepared surfaces. Cross-sections were also taken of the prepared surfaces. The prepared surfaces were coated with zinc-filled coating. The adhesion of the coating to the substrate was evaluated by a pull-off test after curing the coating (as sprayed), as well as after exposure to severe corrosive environments. The best adhesion of the coating was found for the coating applied to the substrate which had been pre-treated with brown corundum and steel grit.