共查询到20条相似文献,搜索用时 140 毫秒
1.
应用声表面波气相色谱快速定性分析姜黄挥发油。声表面波气相色谱采用DB-5毛细管色谱柱,初始温度45℃,6℃/s程序升温至160℃,检测结果与气相色谱质谱结果进行比较。姜黄挥发油定性分析中, 声表面波气相色谱20s完成检测,而气相色谱-质谱需要30min完成,声表面波气相色谱检测更高效;同时,声表面波气相色谱与气相色谱质谱共同检测出姜黄挥发油中10种化学成分,且10种化学成分相对百分含量总和占挥发油总成分的90%以上,由于色谱柱长度区别,声表面波气相色谱检出的化学成分相对较少;定量分析中,对声表面波气相色谱进样方式进行了考察,顶空进样与液体进样对化学成分相对百分含量检测有较大差异;采用与气相色谱质谱一致的液体进样方式,对姜黄挥发油中反式石竹烯定量分析,声表面波气相色谱最低检出限可以达到16.9 pg,在0.001624~0.01624 mg/mL范围内R=0.9976具有较好的线性关系,且精密度和重复性较好。声表面波气相色谱能够用于姜黄挥发油的快速定性和定量分析,为中药挥发油的分析提供了新的快捷的检测技术基础。 相似文献
2.
气相色谱法测定柑橘与土壤中氟啶虫胺腈的残留量 总被引:2,自引:0,他引:2
建立了柑橘和土壤中氟啶虫胺腈残留量的气相色谱测定方法.柑橘全果、果肉和土壤样品中的氟啶虫胺腈用乙腈提取,果皮样品用乙腈-水(4:1,V/V)混合溶剂提取,经中性氧化铝柱净化,浓缩后采用气相色谱-电子捕获检测器(GC-ECD)检测,结果表明,在添加浓度为0.05-1.0mg/kg时,氟啶虫胺腈在样品中的平均回收率为81.3%-101.2%,相对标准偏差为0.9%-4.9%.方法的检出限(LOD)为5.0× 10-11g,氟啶虫胺腈在全果、果肉、果皮和土壤中的最低检测浓度(LOQ)为0.05mg/kg.该方法杂质干扰少,准确性及灵敏度满足农药残留检测的基本要求,对检测硬件要求低,适用于柑橘和土壤中氟啶虫胺腈残留的分析. 相似文献
3.
利用顶空固相微萃取-气相色谱-质谱联用技术分析马蹄香挥发油的化学成分,为马蹄香的挥发油成分分析提供新方法。以顶空固相微萃取法提取挥发油,气相色谱-质谱联用技术对挥发油成分进行分离鉴定,并采用面积归一化法确定各成分的相对质量分数。结果样品在90℃下平衡30min,顶空吸附15min的条件下,采用100μm PDMS纤维头能有效地吸附马蹄香挥发油成分。气相色谱-质谱联用技术共鉴定出57个成分,其中相对质量分数较高的有西车烯(15.93%)、1,2,3,5,6,7,8,8a-八氢-1,4-二甲基-7-(1-甲基乙烯基)甘菊蓝(13.55%)、α-广藿香烯(9.50%)等。马蹄香挥发油具有丰富的化学成分,顶空固相微萃取-气相色谱-质谱联用能全面快速地获得其组成信息,可应用于马蹄香挥发油成分的研究。 相似文献
4.
《应用声学》2021,(3)
应用声表面波气相色谱仪快速定性分析姜黄挥发油。声表面波气相色谱仪采用DB-5毛细管色谱柱,初始温度45℃,按6℃/s程序升温至160℃,将检测结果与气相色谱-质谱仪结果进行比较。在姜黄挥发油定性分析中,声表面波气相色谱仪20 s完成检测,而气相色谱-质谱仪需要30 min完成,声表面波气相色谱仪检测更高效;同时,声表面波气相色谱仪与气相色谱-质谱仪共同检测出姜黄挥发油中10种化学成分,且10种化学成分相对百分含量总和占挥发油总成分的90%以上,由于色谱柱长度区别,声表面波气相色谱仪检出的化学成分相对较少;定量分析中,对声表面波气相色谱仪进样方式进行了考察,顶空进样与液体进样对化学成分相对百分含量检测有较大差异;采用与气相色谱-质谱仪一致的液体进样方式,对姜黄挥发油中反式石竹烯定量分析,声表面波气相色谱仪最低检出限可以达到16.9 pg,在0.001624~0.01624 mg/mL范围内R=0.9976具有较好的线性关系,且精密度和重复性较好。声表面波气相色谱仪能够用于姜黄挥发油的快速定性和定量分析,为中药挥发油的分析提供了新的快捷的检测技术基础。 相似文献
5.
6.
中空纤维膜液相微萃取-GC-MS测定水果和蔬菜中三唑类杀菌剂残留量 总被引:1,自引:0,他引:1
研究了一种直接快速测定水果和蔬菜等固体样品中5种三唑类杀菌剂残留量的新方法,以气相色谱-质谱联用技术为基础,利用中空纤维膜液相微萃取提取固体样品中目标物。通过实验确定最佳萃取条件为:萃取剂为环己烷,固体样品与水的比例为1:3(总质量为10g),超声震荡5min后以500r/min的搅拌速率在40℃下萃取20min。萃取后取1μL有机溶剂直接进样进行气相色谱质谱分离检测。在此条件下,水果和蔬菜中的三唑酮和多效唑的线性范围为0.5—25mg/kg,腈菌唑、烯唑醇和丙环唑的线性范围为1—25mg/kg;5种目标物的检出限均低于0.210mg/kg;相对标准偏差在4.7%—8.1%之间。该方法可以用于水果和蔬菜等固体样品中三唑类杀菌剂的快速测定。 相似文献
7.
8.
9.
10.
11.
Falko Riechert Guy Verschaffelt Georg Bastian Ingo Fischer 《Optics Communications》2008,281(17):4424-4431
We present a technique to reduce the speckle contrast of a NIR broad-area VCSEL based on the spatially incoherent emission regime that can be obtained when using the proper driving conditions. We evaluate the efficiency of this technique to reduce the speckle contrast by comparing it with the speckle characteristics in multimode emission under cw operation. Depending on the illumination setup, the incoherent emission regime can lead to a strongly reduced speckle contrast down to 1.3%. This is in agreement with estimates of the expected speckle contrast reduction when three contrast reducing effects are taken into account. These low contrast values make the investigated sources attractive for several applications that suffer from speckle noise. 相似文献
12.
SHEN Cheng-Ping 《中国物理C(英文版)》2010,34(6):615-620
In this paper, I review recent progress in the study of the XYZ particles at Belle. I only focus on studies with charmonium and one or more light mesons in the final states. This covers the X(3872), X(3915),Y(4140), X(4350), and the charged Z states. 相似文献
13.
This paper studies optical transmission through an interface between two slits with different widths in a sheet composed of an ideal conductor. Such a structure is of potential use in fabricating optical diode and may be the simplest one compared to other designs. Our calculations show that there is a critical wavelength. When the light wavelength is below the critical wavelength, the transmissivity is unidirectional. The expression of the stable transmissivity as a function of the ratio of the widths of the two slits was obtained analytically. Particularly, at the critical wavelength, the transmissivities are zero. This phenomenon has great potential for application in the manufacture of wavelength blockers. 相似文献
14.
PAUL KELLETT 《Fiber and Integrated Optics》2013,32(5):289-303
This article details the evolution of Ethernet into Gigabit Ethernet and how this LAN-based technology has undergone major transformations over time. From its data rates and distances to supported media and functionality, Ethernet has greatly improved, enabling it to surmount many of its former limitations and in so doing to expand beyond the LAN into the MAN and now even the WAN. In this article, Pioneer Consulting explores the evolution further by focusing on some of the major technological directions in the Ethernet equipment industry. 相似文献
15.
应用第一性原理计算方法研究了碳(C)原子对钨(W)中氢(H)原子稳定性的影响. 本征W中, 当C-H间距离为~2.5 Å时, H的溶解能出现最低值, 此时为H最稳定的位置. W中存在空位时, 由于C的影响, H占据的最佳电子密度面值为0.10 Å-3. 研究发现, W中单空位最多能容纳10个H原子, 且不能形成H分子, 不同于没有C存在的情况, 表明C对W中H稳定性存在很大影响. 此外, 当两个C原子存在于空位中时, H占据的最佳电子密度面值变为0.13 Å-3. 相似文献
16.
Sarla Sharma Rishi VyasSubodh Shrivastava Y.K. Vijay 《Physica B: Condensed Matter》2011,406(17):3230-3233
We report a study on the SHI induced modifications on structural and optical properties of ZnO/PMMA nanocomposite films. The ZnO nanoparticles were synthesized by the chemical route using 2-mercaptoethanol as a capping agent. The structure of ZnO nanoparticles was confirmed by XRD, SEM and TEM. These ZnO nanoparticles were dispersed in the PMMA matrix to form ZnO/PMMA nanocomposite films by the solution cast method. These ZnO/PMMA nanocomposite films were then irradiated by swift heavy ion irradiation (Ni8+ ion beam, 100 MeV) at a fluence of 1×1011 ions/cm2. The nanocomposite films were then characterized by XRD, UV-vis absorption spectroscopy and photoluminescence spectroscopy. As revealed from the absorption spectra, absorption edge is not changed by the irradiation but the optical absorption is increased. Enhanced green luminescence at about 527 nm and a less intense blue emission peak around 460 nm were observed after irradiation with respect to the pristine ZnO/PMMA nanocomposite film. 相似文献
17.
The grain boundary potential and interface state charge density at the grain boundaries of silver sulfide (Ag2S) thin films prepared by chemical conversion of cadmium sulfide (CdS) films have been determined from the dc resistance of the material and are found to be sensitive to annealing. A reduction in the grain boundary potential and the grain boundary charge density of the film has been noticed when the source CdS film is annealed at different temperatures prior to chemical conversion. The variation in the grain boundary charge density of the grown Ag2S film with source annealing temperature has been found to be similar to that of thin cadmium sulfide film, reported earlier. An additional low temperature heat treatment of the sample results in an enhancement in the charge density at the grain boundaries. The change in the silver vacancy and/or oxygen and sulfur content of the films as revealed from the energy dispersive spectra of the films suggests possible role of film composition on the grain boundary charge density. 相似文献
18.
Abstract The performance of a wavelength division multiplexing (WDM) system with optical cross-connects (OXCs) and in the presence of polarization and nonlinear effects was analyzed. We determined the effect of PMD and PDL; nonlinearity such as XPM, SPM, and FWM; and CD on the system performance. We found that the system outage probability is highest at DGD threshold for the respective maximum eye closure (EC). We showed that the allowable DGD depends on the time slot for one bit T, which is the inverse of the network bit rate. Wider T is more immune to large PMD with the EC still maintained at the same level since DGD/T is unchanged. Our analysis also indicated that as DGD increases, BER increases. The BER also increases with increase in PDL and further increases with the presence of XPM, SPM, FWM, and CD. 相似文献
19.
The performance of a wavelength division multiplexing (WDM) system with optical cross-connects (OXCs) and in the presence of polarization and nonlinear effects was analyzed. We determined the effect of PMD and PDL; nonlinearity such as XPM, SPM, and FWM; and CD on the system performance. We found that the system outage probability is highest at DGD threshold for the respective maximum eye closure (EC). We showed that the allowable DGD depends on the time slot for one bit T, which is the inverse of the network bit rate. Wider T is more immune to large PMD with the EC still maintained at the same level since DGD/T is unchanged. Our analysis also indicated that as DGD increases, BER increases. The BER also increases with increase in PDL and further increases with the presence of XPM, SPM, FWM, and CD. 相似文献
20.
在流动注射系统中,利用巯嘌呤在碱性Luminol-K3Fe(CN)6化学发光体系中发光信号强的特点,建立了一种测定巯嘌呤的新方法。在优化条件下,方法的线性范围是1.02×10-7~1.02×10-9mol·L-1, 回归方程是Y=36.315c+140.72(Y是相对发光强度,c是巯嘌呤浓度与10-8 mol·L-1的乘积), 相关系数是0.998 2,检出限(S/N=3)是6.33×10-10mol·L-1,RSD为3.54%(ci=2.0×10-9mol·L-1, n=12)。该法用于合成样品的测定,简便、灵敏、快速,结果令人满意。文章简要地探讨了巯嘌呤在碱性Luminol-K3Fe(CN)6化学发光体系中的化学发光机理:在反应过程中,产生大量的过氧自由基和羟基自由基,自由基与鲁米诺反应,形成激发态的鲁米诺分子,鲁米诺分子由激发态回到基态产生化学发光现象。 相似文献