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91.
Summary Hydroxypropyl methyl cellulose (HPMC) and polyethylene glycol 400 (PEG 400) content in HypoTears™ Daily Dose ophthalmic solution
are determined simultaneously by size exclusion chromatography. The retention times of HPMC and PEG 400 are 10.6 and 15.4
minutes, respectively. The method requires minimal sample pretreatment and is accurate and reproducible. The peak area response
from a refractive index detector versus HPMC and PEG 400 concentration is linear over the range of 50–150 % of their label
claims of 2.5 mg/mL and 10 mg/mL, respectively. The mean absolute recoveries of HPMC and PEG 400 at their label claim using
the described method are 98.9±1.3 % and 100.4±1.2 % (mean±SD, n=12), respectively. 相似文献
92.
本文研究并比较了分别以8-羟基喹啉和巯基苯骈噻唑为萃取剂,以活性硅胶为载体的柱式萃取色谱法对环境水中Zn、Cu、Pb、Cd、Fe、Co、Ni和Mn的最佳富集和洗脱条件。实验证明,后者明显优于前者。以巯基苯骈噻唑为萃取剂的色谱柱对金属元素的吸附具有快速、完全、寿命长和重现性好等特点。在pH=7~8之间回收率可达98%以上,富集倍数为200倍。 相似文献
93.
94.
The hydrocarbon discovery prediction problem is important to firms having to make decisions about the deployment of scarce exploration resources. Traditional methods for estimating the discovery rate rely on the completion of time consuming simulation experiments. A rapid approximation that does not require the completion of simulation exists and has been shown to have some promise as a prediction tool. This paper investigates the accuracy of the approximation method under a wide variety of distributional and drilling efficiency assumptions. The results indicate that the approximation produces predictions close to those of simulation under most of the tested conditions. This suggests that resource exploration firms could conveniently use the method for a wide variety of planning purposes without incurring the same costs in time and personnel required for simulation. 相似文献
95.
This contribution discusses the phenomena of retrograde condensation of one or two liquids. It w1 be shown that both phenomena can be well understood. Also the relation of retrograde condensation of one liquid phase with the condensation behavior of natural gas will be discussed. Similarly that of two liquid phases with multiple phase behavior occurring in low temperature reservoir fluids will be pointed out. 相似文献
96.
97.
层流液柱吸收法测定气体在液相中的扩散系数 总被引:2,自引:0,他引:2
采用射流吸收的简捷方法,通过测定由Shouthwell型孔板所产生的截面速度均匀的层流喷射液柱所吸收的气体量,由渗透理论所导出的模型,可计算出一定温度、压力下的微溶气体在液相中的分子扩散系数D。在温度为30~45℃的范围,测试结果与文献值吻合良好. 相似文献
98.
The principle of concentrating a substance from a mixture flow in a stationary sorbent layer of infinite length that was previously
developed for gas chromatography is extended to liquid chromatography.
Translated fromIzevestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1063–1065, May, 1997. 相似文献
99.
The early evolution of gas chromatography in the former German Democratic Republic (GDR) is surveyed and instrument development is outlined, describing the most important models manufactured in the GDR. The organization of the Arbeitsgemeinschaft für Gas-Chromatographie (Working Group for GC) is chronicled and its activities are discussed. Subsequent parts of this article will deal with the six symposia organized by the Arbeitsgemeinschaft between 1958 and 1968. 相似文献
100.
Liquid chromatography-electrospray ionisation mass spectrometry was evaluated in the high-throughput analysis of microcystins and nodularins, cyanobacterial peptide hepatotoxins. Extracts originating from cyanobacterial strains and field material were separated on a 30 mm × 4 mm I.D. Merck Purospher STAR RP-18e column using a rapid gradient of aqueous formic acid and acetonitrile, ionised by electrospray technique and analysed on a Micromass Quattro II triple-quadrupole mass spectrometer operated in the selected ion recording (SIR) mode. The total analysis time per sample was 2.8 min corresponding to 514 samples a day. The system showed good robustness during a series of 320 repetitive injections of a field sample containing three major microcystins. 相似文献