排序方式: 共有39条查询结果,搜索用时 109 毫秒
1.
用共振电离飞行时间质谱仪分析土壤中超痕量气态金 总被引:2,自引:0,他引:2
采用激光共振电离飞行时间质谱技术(简称RIS-TOF技术)对土壤中超痕量气态金的含量进行了分析研究。RIS-TOF谱仪具有极高的灵敏度和很强的选择性,避免了对样品的预富集过程。本文给出了该谱仪对金元素的检测限和65个土壤中气态金样品的分析结果,以及用中子活化法随机抽样检查的结果。 相似文献
2.
Determination of Biodegradation Process of Benzene, Toluene, Ethylbenzene and Xylenes in Seabed Sediment by Purge and Trap Gas Chromatography 总被引:1,自引:0,他引:1
Benzene, toluene, ethylbenzene, and xylenes (BTEX) are commonly found in crude oil and are used in geochemical investigations as direct indicators of the presence of oil and gas. BTEX are easily volatile and can be degraded by microorganisms, which affect their precise measurement seriously. A method for determining the biodegradation process of BTEX in seabed sediment using dynamic headspace (purge and trap) gas chromatography with a photoionization detector (PID) was developed, which had a detection limit of 7.3–13.2 ng L?1 and a recovery rate of 91.6–95.0%. The decrease in the concentration of BTEX components was monitored in seabed sediment samples, which was caused by microorganism biodegradation. The results of BTEX biodegradation process were of great significance in the collection, transportation, preservation, and measurement of seabed sediment samples in the geochemical investigations of oil and gas. 相似文献
3.
激光单分子探测技术的研究 总被引:6,自引:1,他引:6
文中介绍利用激光激发分子荧光的方法探测液体中单个染料分子的新技术,以及作者自行设计和研制的激光单分子探测谱仪。通过探测“光子爆发”,把单个染料分子的荧光同很强的背景杂散光区别开来。进一步用82MHz高重复频率的锁模激光器和时间门符合技术,成功地消除了Raman散射光。目前该谱仪达到的检测限为灵敏区内仅有~7个R6G分子。 相似文献
4.
5.
Wensheng Huang Chunhai Yang Wanyun Qu Shenghui Zhang 《Russian Journal of Electrochemistry》2008,44(8):946-951
In this work, an electrochemical method for the determination of malachite green was developed on the basis of enhancement
effect of an anionic surfactant: sodium dodecyl benzene sulfonate. It is found that the oxidation peak current of malachite
green at carbon paste electrode significantly increases in the presence of low concentration of sodium dodecyl benzene sulfonate
in pH 6.5 phosphate buffer, suggesting that sodium dodecyl benzene sulfonate shows obvious enhancement effect for the determination
of malachite green. The experimental parameters, such as supporting electrolyte, kind of surfactant, concentration of sodium
dodecyl benzene sulfonate and accumulation time, were optimized, and then a sensitive and convenient electrochemical method
was proposed for the determination of malachite green. The oxidation peak current is proportional to the concentration of
malachite green over the range from 8.0 × 10−9 to 5.0 × 10−7 mol l−1, and the detection limit is 4.0 × 10−9 mol l−1 after 5 min of accumulation. Finally, this new method was successfully employed to detect malachite green in fish samples.
Published in Russian in Elektrokhimiya, 2008, Vol. 44, No. 8, pp. 1019–1024.
The text was submitted by the authors in English. 相似文献
6.
ZHAO Wanyun 《理论物理通讯》1997,28(4):497-498
By the study for the mixing of a charm quark c and a new quark m with the mixing angle θ in an extended standard model, we obtain the theoretical values of Rb and Rc which are fairly accordant with the experimental values of Rbex and Rcex. 相似文献
7.
8.
毛细管电泳-激光诱导荧光测定大鼠血浆内痕量氨基酸类神经递质 总被引:4,自引:0,他引:4
用菁色素衍生物 (Cy5 )作为荧光衍生试剂 ,毛细管电泳结合激光诱导荧光分离测定痕量氨基酸类神经递质甘氨酸和谷氨酸。讨论了Cy5浓度 ,缓冲液浓度 ,pH值和反应时间等实验条件对衍生和分离的影响。衍生物的荧光强度和氨基酸的浓度在 7.5× 1 0 - 8~ 3 .5× 1 0 - 6 mol L范围内呈现良好的线性 ,线性相关系数均达到 0 .999。甘氨酸和谷氨酸的最低检出限浓度分别为 3 .3× 1 0 - 9mol L和 1 .0×1 0 - 9mol L。测定了大鼠血浆中甘氨酸和谷氨酸的浓度 ,分别为 (62± 1 4 )× 1 0 - 6 mol L和 (1 9± 2 )× 1 0 - 6 mol L。与其它氨基标记荧光试剂 ,如FITC和TRITC相比 ,Cy5与一级胺反应时间短 ,选择性高 相似文献
9.
吹扫捕集-气相色谱分析海水和沉积物中的苯、甲苯、乙苯及二甲苯 总被引:4,自引:0,他引:4
单环芳烃苯、甲苯、乙苯和二甲苯(简称BTEX)是石油的重要组分,也是环境中需要重点监测的致癌污染物。本实验建立了动态顶空(吹扫捕集)和光离子化检测器的气相色谱测量海水、沉积物中痕量BTEX的方法。在120—1200ng/L的浓度范围,苯、甲苯、乙苯、间对二甲苯及邻二甲苯标准溶液的检出限分别为6.4、35.2、15.8、12.3、10.7ng/L,相对标准偏差0.9%-6.1%。样品无需预处理,海水中BTEX回收率为93.50%-98.40%。7个渤海表层海水样品中BTEX的浓度均低于140ng/L;海底沉积物中苯、甲苯、乙苯、间对二甲苯及邻二甲苯浓度分别为169—1243、531—1732、1308—5624、237—1136、510—5194ng/L。测量方法和结果对评价环境污染具有重要意义。 相似文献
10.
激光原子荧光光谱分析法的进展 总被引:5,自引:0,他引:5
概述了激光原子荧光光谱分析法的研究现状和发展趋势。对各种原子化学方法与激光原子荧光光谱分析法相结合的分析特性进行了描述,着重介绍了电热原子化作为原子化器的激光原子荧光光谱法近年来的发展和应用。 相似文献