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马山前胡挥发油化学成分研究 总被引:5,自引:0,他引:5
本文用毛细管气相色谱、气相色谱/质谱/计算、气相色谱/红外光谱等现代仪器分析技术,对马山前胡挥发油的化学成分进行了分析研究,从毛细管色谱分离出80多个峰,确认了其中37种成分,占色谱总馏出峰面积的97%以上,该挥发油的主要化学成分为蒎烯。 相似文献
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气相色谱法对乙醛多聚体的质量全分析 总被引:4,自引:0,他引:4
1引言 四聚乙醛是一种白色针状结晶,易燃,有工业固体酒精之称。可用作固体燃料、塑料发泡剂和杀灭蜗牛、蛞蝓等有肺类软件害虫和吸血虫寄生的钉螺等,还可用于安全火柴、焰火和人工降雨等方面。国外研究开发该产品始于40年代。我厂经过多年的努力,于1996年实现了工业化生产。然而该产品的分析方法则是一个难题。Vasyagina等研究了气相色谱法,但该方法重现性差,误差也大。1994年西安近代化学研究所也研究了气相色谱法,该方法对四聚乙醇和三聚乙醛分别测定,故有诸多的局限性。本工作使用气相色谱法,结合校正因子… 相似文献
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动力学分析法测定气相中的二氧化碳 总被引:2,自引:0,他引:2
本文基于气相中的二氧化碳在稀氢氧化钠-酚酞溶液中的溶解而使酚酞逐渐褪色的动力学行为提出了一种直接测定气相中微量二氧化碳的动力学分析法。研究表明,该反应的速率与气相中CO2的浓度成正比。利用固定浓度法,本文测定了一些模拟样品和环境气体样品,效果良好。该方法仪品简单,样品不必预处理。 相似文献
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气相色谱—表面发射火焰光度检测法测定环境水样中的二辛基锡 总被引:2,自引:0,他引:2
建立了测定环境水样中二辛基锡化合物的气相色谱法。该法用硼氢化钠把二辛基锡氯化物衍生成氢化物,以二氯甲萃取后,用气相色谱-表面发射火焰光度检测器分析测定。 相似文献
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本文建立了人血中十种单端孢霉烯族毒素的气相色谱(电子捕获检测器)和气相色谱-质谱(气质)联用分析法。该法采用乙酸乙酯萃取血中毒素后,将萃取液浓缩至干,用七氟丁酰咪唑衍生化,用气相色谱和色/质联用分析测定。方法的最低检出限为1~10ng/mL血,回收率为60.8~101.1%。 相似文献
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本文建立了人血中十种单端孢霉烯族毒素的气相色谱(电子捕获检测器)和气相色谱-质谱(气质)联用分析法。该法采用乙酸乙酯萃取血中毒素后,将萃取液浓缩至干,用七氟丁酰咪唑衍生化,用气相色谱和色/质联用分析测定。方法的最低检出限为1~10ng/mL血,回收率为60.8~101.1%。 相似文献
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倍硫磷的气相色谱/红外光谱检测 总被引:2,自引:0,他引:2
倍硫磷是我国常用农药品种,也是是 口大米的必检项目之一。本文应用气相色谱/红外光谱联用方法,探索了倍硫磷的最佳色谱条件,获得其气以谱/红外光谱图,并依靠已有的气相红外谱库进行了检索,拟建立倍硫磷的气相色谱/红外谱库,以用于农产品中该农药的GC/FTIR监控。 相似文献
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Steven T. Parslow Najlaa K. Almazrouei Michael I. Newton Elizabeth R. Dye Robert H. Morris 《Magnetic resonance in chemistry : MRC》2019,57(9):695-699
Moisture content of foodstuffs are typically assessed by Titration or Near Infrared Spectroscopy, which are labour-intensive as a manual measurement or costly when automated. Magnetic resonance offers a method for moisture evaluation but is also normally costly. In this work, we revisit Look and Locker's “Tone Burst” experiment with a marginal oscillator to evaluate moisture content of powdered–skimmed milk subjected to increased humidity. We refer to this technique as the Transient Effect Determination of Spin–Lattice (TEDSpiL) relaxation times. Moisture content in the samples ranged from 0–12% as determined from the weight gained by the dry powder when re-suspended in water to reach a concentration of 40% w/v. The relaxation properties of re-hydrated samples were measured with a CW NMR sensor. Solutions made up from powders with a higher retained moisture content provided lower measured relaxation values providing a method of measuring the moisture content of the powder. This technique provides a moisture measurement in under 5∼s compared with several minutes for the equivalent pulsed method using low-field hardware. 相似文献
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《Radiation Physics and Chemistry》2009,78(5):303-306
Among the available nuclear techniques, the neutron backscattering technique, based on the detection of the produced thermal neutrons, is thought to be the most promising for landmine detections.The results obtained from Monte Carlo simulation were used for selection of BF3 detector and Am–Be neutron source shielding. In addition, soil moisture was discussed as a limitation of the neutron backscattering technique. It was experimentally found that this technique is useful for soil whose water content is lower than 14%. 相似文献
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A quantitative and qualitative technique for identification of textiles, moisture measurements, textile coatings and process control was developed, using near infra-red spectroscopy (NIR) in combination with chemometric methods. These applications demonstrate by the use of computer assisted data processing the possibility of identifying textile fibers, not only for quality control but also for online textile recycling processes. In this study, seven various textile fibers (cotton, polyester, viscose, silk, wool, polyacrylonitrile, acetate) were used and all combinations of two factor blends were qualitatively identified using NIR spectroscopy and the chemometric PLS2 method for the calibration.
A quantitative analysis of textile moisture can also be performed with this technique. Water content above 50% does not deliver good results for a calibration set to determine the dampness of fibers. But to measure residual moisture from ≈0.05 up to 50%, the NIR technique is particularly good. Furthermore, the examination shows that the NIR method and chemometric methods can be used in quality- and product-control during the industrial production of upholstery fabrics. With this technique it will be possible to identify nylon flocks and to measure the residual moisture of the flocks and fabric, too. 相似文献
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微波谐振腔微扰技术检测造纸法再造烟叶水分 总被引:1,自引:0,他引:1
研究了基于微波谐振腔微扰技术检测造纸法再造烟叶水分的方法.用最小二乘法探讨了不同微波测量参数与造纸法再造烟叶水分含量的校准模型,并将检测结果与标准烘箱法进行了比较.研究表明:该方法的测量误差小于0.4%,检测的响应速度仅为 0.1 ms. 相似文献
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Differential scanning calorimetry (DSC) was used to determine the starch content of potato dry matter isolated from various cultivars at different times during growth. When potato dry matter was heated in the presence of excess water, a symmetrical endothermic peak resulted, which was similar to the gelatinization peak of pure starch. From the enthalpy value of potato dry matter and pure potato starch at a moisture content of 70%, the starch content in the potato dry matter can be determined. Starch content increased as growth progressed to a maximum and then decreased. The effect of moisture content and sample mass on gelatinization of dry matter and starch was also investigated. Compared to other starch analysis technique, DSC is a simple and more rapid method. 相似文献
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Grunlan JC Mehrabi AR Chavira AT Nugent AB Saunders DL 《Journal of combinatorial chemistry》2003,5(4):362-368
A high-throughput method for screening the moisture vapor transmission rate of barrier films was developed. This moisture high-throughput screening (MHTS) technique is based upon a Nafion-crystal violet (CVN) sensor that changes color from yellow to green upon absorption of water. Using an appropriate set of known standards, the slope of absorbance (at 630 nm) as a function of time can be converted into moisture vapor transmission rate (MVTR) values that agree with those obtained using ASTM F1290. High-throughput screening was demonstrated by depositing 20 emulsion-based poly(vinylidene chloride) films, using a 48-well template, of varying thicknesses onto the CVN sensor film and aging at 40 degrees C and 90% relative humidity for 72 h. MVTR values were accurately determined to a level of 0.9 g/m(2).day, at which point side-diffusion of moisture between the barrier and sensor films prevented observation of lower values. Larger sample size and edge-sealing are two proposed methods for improving the sensitivity of MHTS. 相似文献
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XIAOPeng GUOXin-xin CUIYing-xin RobertE.Imhof DaneBicanic 《高等学校化学研究》2004,20(4):417-420
Opto-thermal transient emission radiometry(OTTER) is a infrared remote sensing technique, which has been successfully used in in vivo skin moisture content and skin moisture depth profiling measurements. In present paper, we extend this moisture content measurement capability to analyze the moisture content of fruit (tomato. grape, etc. ) skins, and to study the relationship between fruits ripening process and their sur-face moisture and moisture depth profiles. 相似文献
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研究了近红外光谱技术快速检测红曲菌固态发酵过程参数水分含量和pH值的可行性。针对传统基于间隔策略波长选择方法忽略非线性因素的缺点,采用一种基于最小二乘支持向量机(Least squares support vector machines,LS-SVM)非线性模型的波长筛选算法:联合区间最小二乘支持向量机(Synergy interval least squares support vector machines,siLS-SVM),并将新算法与相关系数法、iPLS算法、siPLS算法对比。实验结果显示,联合siLS-SVM算法和LS-SVM模型取得了最好的预测效果,水分含量、pH值的预测集相关系数(Rp)分别为0.962 1、0.976 1,预测均方根误差(RMSEP)分别为0.012 9、0.145 2,表明模型具有较好的拟合度和预测性能。应用近红外光谱法进行红曲菌固态发酵过程的水分含量和pH值的快速检测可行,该方法为进一步实现其过程参数的在线检测及发酵条件优化提供了技术基础。 相似文献
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Donatella Capitani Noemi Proietti Marco Gobbino Luigi Soroldoni Umberto Casellato Massimo Valentini Elisabetta Rosina 《Analytical and bioanalytical chemistry》2009,395(7):2245-2253
An integrated study of microclimate monitoring, IR thermography (IRT), gravimetric tests and portable unilateral nuclear magnetic
resonance (NMR) was applied in the framework of planning emergency intervention on a very deteriorated wall painting in San
Rocco church, Cornaredo (Milan, Italy). The IRT investigation supported by gravimetric tests showed that the worst damage,
due to water infiltration, was localized on the wall painting of the northern wall. Unilateral NMR, a new non-destructive
technique which measures the hydrogen signal of the moisture and that was applied directly to the wall, allowed a detailed
map of the distribution of the moisture in the plaster underlying the wall panting to be obtained. With a proper calibration
of the integral of the recorded signal with suitable specimens, each area of the map corresponded to an accurate amount of
moisture. IRT, gravimetric tests and unilateral NMR applied to investigate the northern wall painting showed the presence
of two wet areas separated by a dry area. The moisture found in the lower area was ascribed to the occurrence of rising damp
at the bottom of the wall due to the slope of the garden soil towards the northern exterior. The moisture found in the upper
area was ascribed to condensation phenomena associated with the presence of a considerable amount of soluble, hygroscopic
salts. In the framework of this integrated study, IRT investigation and gravimetric methods validated portable unilateral
NMR as a new analytical tool for measuring in situ and without any sampling of the distribution and amount of moisture in
wall paintings. 相似文献