HPLC法测定刺五加软胶囊中刺五加苷E的含量

目的:建立刺五加软胶囊中刺五加苷E的含量测定方法。方法:采用HPLC法测定,使用Diamonsil C18(250mm×4.6mm,5μm)色谱柱,流动相:乙腈-0.1%磷酸溶液(15:85),流速:1.0ml/min,检测波长:210nm。结果:刺五加苷E对照品在10.16μg/ml～91.44μg/ml范围内有良好线性关系(r=0.9998),平均回收率为98.06%,RSD=1.3%(n=6)。结论:该法操作简便、准确、重现性好,可作刺五加软胶囊中刺五加苷E的质量控制方法。     

超临界流体辅助醋酸纤维素溶液加工的流变性能

为了改善二醋酸纤维素(CDA)加工的流变性能,采用超临界二氧化碳辅助CDA溶液单螺杆挤出加工,通过狭缝流变仪进行流变测试,研究了注入超临界二氧化碳和加工条件(挤出温度、溶剂含量)对CDA溶液流变行为的影响。结果表明,CDA溶液和CDA/CO_2溶液体系均是非牛顿假塑性流体;CDA溶液和CDA/CO_2溶液体系的剪切黏度随着挤出温度或溶剂量的增加而降低;注入超临界二氧化碳显著降低了CDA溶液的黏度、挤出温度、剪切黏度对温度的敏感程度、口模压力和溶剂量,提高CDA溶液的挤出流量和非牛顿指数。随着温度升高,6 r/min和8 r/min时CDA/CO_2溶液体系黏度下降值大,黏度降低值可以达到47.93%;同一溶剂含量下,6 r/min时注入超临界二氧化碳后CDA溶液黏度下降值较大,降低值可以达到48.10%。     

异福双释胶囊中的利福平和异烟肼的含量测定研究

建立抗结核二联药异福双释胶囊中的利福平和异烟肼的含量测定方法。方法:采用HPLC法以辛基硅烷键合硅胶为填充剂;以0.01mol/L庚烷磺酸钠溶液(稀磷酸调PH值至2.2)-乙腈(44:56)为流动相;检测波长为254nm。结果:异烟肼在0.003～0.06mg/ml的浓度范围内呈一直线,回归方程为Y=72309833X+32453,r=0.9998(n=5);利福平在0.0059～0.12mg/ml的浓度范围内呈一直线,回归方程为Y=74006675X+29953,r=0.9997(n=5)。结论:该方法简便、稳定、可靠,可用于异福双释胶囊的质量控制。     

汽车动力总成冷却风扇优化设计

某汽车动力总成冷却风扇风量较低,辐射气动噪声较大,不满足设计要求,对该风扇进行改进优化设计,并对改进前后的风扇在试验台架上进行气动性能测试对比,在整车上进行车内外噪声测试对比,测试结果表明,改进后风扇在3 000 r/min时,标准风量由1 823.9 m~3/h增大到2 375.7 m~3/h,增大30.3%,静压效率无明显变化,功率略增大,改进后扇叶叶片旋转噪声的1阶和2阶明显降低,在2 600 r/min转速下,总声压级从70.41 dB(A)降低到66.31 dB(A),降低4.1 dB(A),扇叶叶片1阶声压级从67.87 d B(A)降低到56.91 dB(A),降低10.96 dB(A)。     

高效液相色谱法测定吡磺环已脲血药浓度的改进

本文就HPLC法测定吡磺环已脲的血药浓度进行了改进。色谱柱为ODS C_(18)柱,流动相为乙腈—甲醇—水(30:25:45)的混合溶液,pH3.5。甲醇沉淀血浆中蛋白,离心后取上清液直接进样,检测波长275nm。回收率大于95％,RSD小于10％,血浆中最低检测浓度10ng/ml,在0.02～1.00μg/mi浓度范围内,r=0.9996。方法简便、快速、灵敏度高,可推广应用。     

单通氧化铝模板的制备及工艺优化

利用高纯铝片采用两步阳极氧化法制得排列高度有序、尺寸可控的单通氧化铝(anodic aluminum oxide templates,AAO)模板,且纳米孔呈六方形结构。分别探究了预处理条件、氧化次数、扩孔时间等对AAO模板尺寸及有序性的影响。结果表明,预处理利于纳米管形成高度有序结构,并发现二次阳极氧化法比一次阳极氧化法制备的纳米管排列更有序且孔径均匀;在0~75 min内,管孔径与扩孔时间呈线性关系,酸溶液对孔的腐蚀速率为0.601nm/min,在0~120min内,管长度与二次氧化时间呈线性关系,生长速率为0.28μm/min;最佳电解液浓度确定为0.3mol/L。为后续制备非对称丝岛状骨组织再生高分子薄膜奠定了良好基础。     

溶液聚合体系中丙烯腈和N-乙烯基咪唑单体竞聚率的测定

以偶氮二异丁腈(AIBN)为引发剂,N,N-二甲基甲酰胺(DMF)为溶剂,在N2气氛中,70℃时采用自由基溶液聚合法进行了丙烯腈(AN)和N-乙烯基咪唑(VIM)的共聚合反应。采用核磁共振氢谱对不同单体投料比条件下得到的P(AN-co-VIM)的组成进行了测定。分别用F-R法、K-T法计算了2种单体的竞聚率。结果为F-R法r1=0.12,r2=0.61;K-T法r1=0.14,r2=0.67。     

ICP-OES法测定焊锡中铅铜银等多种元素

本文用电感耦合等离子发射光谱法(ICP-AES)同时测定测焊锡中的多种金属元素,用硝酸-氢氟酸混酸溶解样品,加入硫脲稳定溶液中的银离子。以基体匹配法配制工作曲线标样,有效地消除了基体干扰。方法简便、可靠,能满足焊锡样品测定的要求。     

基于SVD差分谱去噪法分析地铁调车测试噪声

在对地铁调车进行室内噪声测试时,无法避免不确定因素对信号的干扰,为得到机车室内室外的噪声值以及理想的频谱信息,需要对地铁调车整体进行同步测试和信号去噪。在通过传声器同步测试地铁调车室内噪声后,发现二位端司机室测点在发动机转速750,1 000,1 200 r/min 3个工况下噪声值为75.6～80.1 dB(A),满足国标限值;在发动机转速1 500,1 800,2 100 r/min 3个工况下噪声值为82.5～92 dB(A),属于超标。室外噪声均满足国标限值。在使用奇异值分解差分谱法对二位端司机室测试信号去噪后,得到较为理想的测试信号频谱,同时通过分析频谱可知在63 Hz处出现异常,并且以630 Hz为中心频率。分析结果可以作为后期车辆降噪工作整改参考。     

蒸汽爆破预处理对稻草刨花板性能的影响

稻草SiO2含量较高,并且表皮被光滑的斥水性的蜡层所覆盖,无法使用传统的脲醛树脂(UF)制造稻草刨花板。采用蒸汽爆破法预处理稻草,预处理温度分别为160和170℃,时间分别为2,4和6 min。以预处理后的稻草为原料,利用UF为胶粘剂制作稻草刨花板。实验结果表明,经过160℃,停留时间为6 min和170℃,停留时间分别为4与6 min预处理的稻草制备的刨花板的强度性能达到了国标GB/T 4897-2003的要求。     

Ultra-trace determination of silver in water samples by electrothermal atomic absorption spectrometry after preconcentration with a ligand-less cloud point extraction methodology

A very simple and ligand-less cloud point extraction (CPE) methodology for the preconcentration of ultra-trace amounts of silver as a prior step to its determination by electrothermal atomic absorption spectrometry (ETAAS) has been developed. The method is based on the extraction of silver at pH 9 by using non-ionic surfactant polyethyleneglycolmono-p-nonylphenylether (PONPE 7.5) without adding any chelating agent. Several important variables that affect the CPE efficiency and ETAAS signal were investigated and optimized. The preconcentration of 15 ml sample solution allowed us to achieve an enhancement factor of 60. The calibration graph using the preconcentration system was linear in the range of 5-100 ngl(-1) with a correlation coefficient of 0.9991. The lower limit of detection (3s) obtained in the optimal conditions was 1.2 ngl(-1). The relative standard deviation (R.S.D.) for eight replicate determinations at 30 ngl(-1) Ag level was 4.2%. The proposed method was successfully applied to the ultra-trace determination of silver in water samples.     

Determination of trace lead in water samples by continuous flow microextraction combined with graphite furnace atomic absorption spectrometry

A new method of continuous flow microextraction (CFME) combined with graphite furnace atomic absorption spectrometry (GFAAS) was proposed for the determination of trace lead in water samples. A drop of 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) dissolved in benzene is injected into a glass chamber by a microsyringe and held at the outlet tip of a PTFE connecting tube, the sample solution flows right through the tube and the glass chamber, the solvent drop interacts continuously with the sample solution, and the analyte was extracted into the drop and concentrated. After extracting for a period of time, the drop was retracted into the microsyringe and directly injected into graphite furnace for determination of Pb. Several factors affecting the extraction efficiency, such as solution pH, sample flow rate, drop volume and extraction time, were optimized. Under the optimized conditions, a concentration factor of 45 was achieved, and the detection limits for Pb were 12 pg mL(-1). The relative standard deviation for six replicate analyses of 10 ng mL(-1) Pb was 6.8%. The proposed method was applied to determine of trace Pb in water samples with satisfactory results.     

戊二醛改性壳聚糖/ 纳米TiO2 复合膜的抗水性研究

采用戊二醛作为交联剂与壳聚糖进行交联,以提高壳聚糖/ 纳米TiO2 膜的抗水性。采用三元二次通用旋转组合设计实验方法,建立了力学性能、吸水率与戊二醛用量、交联时间、TiO2 溶胶添加量的二次回归数学模型,得出了制备戊二醛改性壳聚糖/ 纳米TiO2 膜的最佳工艺条件为交联剂用量0. 10 g/ (100 mL)乙酸溶液,交联时间4. 37 h,TiO2 溶胶添加量0. 08 mL/ (100 mL)的乙酸溶液。上述条件下得到的膜的拉伸强度为5. 69MPa,吸水率为133. 66%。与壳聚糖/ 纳米TiO2 膜相比,吸水率下降了72. 8%。     

高压密封湿法消解—冷原子荧光法测定品成色剂中的微量汞

本文采用聚四氟乙烯高压密封消化罐消化明胶样品,将消化好的样品转移到10ml容量瓶中,用去离子水定容10ml,摇匀。进样1.0ml于冷原子荧光测定仪的反应瓶中,加0.2ml10%SnCl2,品成色剂溶液中的微量汞被SnCl2还原成汞蒸汽,汞蒸汽被氩气带入荧光室,产生荧光。此法测定步骤消解时间短,无汞的挥发损失,干扰少,检出限低为(100ppt),回收率高为(92.1%—95.5%),重复性好,相对标准偏差为2.3%。     

非抑制型离子色谱法测定负印制电路板表面阴离子污染物

本文提出了一种利用非抑制型离子色谱法测定印制电路板表面六种无机阴离子污染物的方法。样品用异丙醇水溶液提取后,用Sep—Pak C_(18)小柱净化试样,用离子色谱分离,电导检测器检测。六种阴离子的检测限介于0.01～0.2μg/ml之间,回收率为98～104％。方法准确,可靠,可用于印制电路板洁净度的评价分析。     

Analysis of n-alkanes in water samples by means of headspace solvent microextraction and gas chromatography

A simple and efficient headspace solvent microextraction (HSME) was developed for the simultaneous determination of the trace concentrations of some n-alkanes in water samples. Therefore, a microdrop of an organic solvent was extruded from the needle tip of a gas chromatographic syringe to the headspace above the surface of the solution in a sealed vial. Then the volatile organic compounds are extracted and concentrated in the microdrop. Next, the microdrop was retracted into the microsyringe and injected directly into the gas chromatograph. Experimental parameters which control the performance of HSME such as the type of microextraction solvent, organic drop and sample volume, sample stirring rate, sample solution and microsyringe needle temperatures, salt addition and exposure time profiles were investigated and optimized. Finally, the enrichment factor, dynamic linear range (DLR), limit of detection (LOD) and precision of the method were evaluated. Using optimum extraction conditions, good linearity with correlation coefficients in the range of 0.995相似文献   

Preconcentration, speciation and determination of ultra trace amounts of mercury by modified octadecyl silica membrane disk/electron beam irradiation and cold vapor atomic absorption spectrometry

Mercury (II) and methyl mercury cations at the Sub-ppb level were adsorbed quantitatively from aqueous solution onto an octadecyl-bonded silica membrane disk modified by 2-[(2-mercaptophyenylimino)methyl] phenol (MPMP). The trapped mercury was then eluted with 3ml ethanol and Hg2+ ion was directly measured by cold vapor atomic absorption spectrometry, utilizing tin (II) chloride. Total mercury (Hgt) was determined after conversion of MeHg+ into Hg2+ ion by electron beam irradiation. A sample volume of 1500ml resulted in a preconcentration factor of 500 and the precision for a sampling volume of 500ml at a concentration of 2.5microgl(-1) (n=7) was 3.1%. The limit of detection of the proposed method is 3.8ngl(-1). The method was successfully applied to analysis of water samples, and the accuracy was assessed via recovery experiment.     

EDTA容量法测定锌合金中的铝量

本文采用称大样和用硝酸溶样,然后加入过量的EDTA,在pH≈5.8时用乙酸锌滴定过量的EDTA,加入氟化铵,释放出与铝络合的EDTA,再用乙酸锌滴定被释放出的EDTA。该方法简单、快速、准确,适用于锌合金中铝量的测定。     

石墨炉原子吸收法测定头发中锌

利用优级纯硝酸浸润,放置过夜,适当水浴加热的方法,将头发制备成溶液,用石墨炉原子吸收法测定头发中锌,在选定的测定条件下检出限0.01mg/l、精密度2.3%、准确度实验的回收率在95.0%~101.2%之间。     

水中汞的电感耦合等离子体-质谱法测定

为解决水中汞不稳定以及易吸附而引起记忆效应的问题,建立分析水中汞的电感耦合等离子体质谱新方法,汞标准溶液中加金形成金汞齐,采用200μg/LAu2＋-5%HNO3溶液作为清洗液,选取Rh103作为内标元素。结果标明：在79d内,汞溶液的标准曲线稳定,其相关系数在0.9993~0.9998之间,仪器检出限在1.15×10-3~3.11×10-2μg/L范围内。该方法分析水中痕量汞具有检出限低、数据准确性高、再现性好的特点,所用试剂种类少且毒性小。