Recording Spatially Resolved Plasma Parameters in Microwave-Driven Plasmas

In an almost cubical reactor 90 1 in volume which is intended to deposit organic polymers by plasma-enhanced chemical vapor deposition （PECVD）, microwave power is coupled into the volume via a quartz window which extends to approximately 1/10 of the sidewall area. Since the plasma is excited locally, plasma parameters like electron temperature and plasma density are expected to exhibit a spatial variation. The compilation of these plasma quantities has been accomplished with a bendable single Langmuir probe. To isolate the tungsten wire against its grounded housing tube, it was coated with polyparylene. After having compared this construction with our Langmuir probe, which has been now in use for more than a decade, we have taken data of more than half the volume of the reactor with argon and have found a definitive radial inhomogenity for all plasma parameters. To investigate whether this conduct can be determined applying optical emission spectroscopy, we improved our spectrometer which had been used for endpoint detection purposes and plasma diagnostics in chlorine-containing ambients where we could detect also a spatial dependence. This behavior is discussed in terms of Lieberman＇s global model.

Correlation ofⅢ/Ⅴsemiconductor etch results with physical parameters of high-density reactive plasmas excited by electron cyclotron resonance

Reactive ion etching is the interaction of reactive plasmas with surfaces. To obtain a detailed understanding of this process, significant properties of reactive composite low-pressure plasmas driven by electron cyclotron resonance（ECR） were investigated and compared with the radial uniformity of the etch rate. The determination of the electronic properties of chlorine-and hydrogen-containing plasmas enabled the understanding of the pressure-dependent behavior of the plasma density and provided better insights into the electronic parameters of reactive etch gases. From the electrical evaluation of I（V） characteristics obtained using a Langmuir probe,plasmas of different compositions were investigated. The standard method of Druyvesteyn to derive the electron energy distribution functions by the second derivative of the I（V）characteristics was replaced by a mathematical model which has been evolved to be more robust against noise, mainly, because the first derivative of the I（V） characteristics is used. Special attention was given to the power of the energy dependence in the exponent. In particular, for plasmas that are generated by ECR with EM modes, the existence of Maxwellian distribution functions is not to be taken as a self-evident fact, but the bi-Maxwellian distribution was proven for Ar-and Kr-stabilized plasmas. In addition to the electron temperature, the global uniform discharge model has been shown to be useful for calculating the neutral gas temperature. To what extent the invasive method of using a Langmuir probe could be replaced with the noninvasive optical method of emission spectroscopy, particularly actinometry, was investigated,and the resulting data exhibited the same relative behavior as the Langmuir data. The correlation with etchrate data reveals the large chemical part of the removal process—most striking when the data is compared with etching in pure argon. Although the relative amount of the radial variation of plasma density and etch rate is approximately ？5%, the etch rate shows a slightly concave shape in contrast to the plasma density.

The Role of the European Pharmacopoeia(Ph Eur)in Quality Control of Traditional Chinese Herbal Medicine in European Member States

In order to assure the safety and efficacy of the Chinese Medicines in Europe, the quality of TCM herbals should be guaranteed so that they can be freely imported in the European Union and other Western European Countries which are signatories of the European Pharmacopoeia Convention. Consequently, new Ph Eur TCM herbal drug Monographs should be elaborated, based on preexisting Monographs in the Chinese Pharmacopoeia(Ch P) 2010.Such a program has been inaugurated in 2005 by the Ph Eur Groups of Experts 13 A and B(Phytochemistry). Since then good progress has been made, elaborating of about one third of the originally proposed 100 TCM herbals being identified as important monographs for the European Market. Taking into account the many challenges still laying ahead, the establishment of a specialized Working Party(WP) on TCM with specialists and experts from many EU Member States has been decided by the Ph Eur Commission in 2008 which is highly active ever since in the examination and elaboration of new TCM herbal drug monographs, primarily to assure the safety of the European patient and further to provide quality parameters extremely important for all registration and licensing procedures of the respective National Authorities all over Europe.This paper is a survey of results and difficulties obtained so far which has been encountered meanwhile in the elaboration process by the Ph Eur TCM WP of these monographs and will discuss these in detail. Moreover the role of Ph Eur TCM monographs in the European community is addressed.

Quantitative Analysis of Eight Ginsenosides in Red Ginseng Using Ginsenoside Rg1 as Single Reference Standard

Objective:To develop a reversed-phase high-performance liquid chromatography method for the quantification of major ginsenosides in red ginseng(RG,the steamed and dried root of the cultivar of Panax ginseng C.A.Mey).Methods:A feasible method was developed in strict accordance with chromatographic properties of eight ginsenosides.Their contents could be unveiled with conventional external standard method,or as an alternative,using ginsenoside Rg1 as the single reference standard by means of seven conversion factors.Those parameters had been validated on different chromatographic columns and instruments.Results:Twenty-one batches of RG samples were determined.In addition,the chromatograms of RG and confusing species,including Panax ginseng,Panax quinquefolium,and Panax notoginseng,were apparently different.Conclusions:The method was proved to be efficient for the quality control of RG.

INTRODUCTION OF ASIAN HERBAL MEDICINES IN THE EUROPEAN PHARMACOPOEIA: RELEVANCE OF THE CURRENT ASSAY POLICY

Herbal drugs have a long tradition as medicines for the European market.They are recognized within the regulatory framework of the European Union(EU)on medicinal products like all kinds of medicines.All herbal drugs and the products made thereof have to proof their quality and safety prior to gaining access to the market.The concern about the safety of TCM herbal drugs in the

Comparison of Granules for Prescription and Classical Decoctions by High-performance Thin-layer Chromatography-fingerprint Analysis

Objective: The so?called granules for prescription have been developed about 20 years ago as a new form of modernizing and simplification of the classical decoction common in Traditional Chinese Medicine (TCM) practice. Due to actual problems in Germany/Europe, which are caused by the lack of quality monographs and judicial classification of granules for prescription, the aim of the study was a comparison of the chemical composition of commercial granules versus decoctions. Taking an example, decoctions, commercial granules, and organic extracts of two well?established TCM herbal drugs, Scrophulariae Radix and Xanthii Fructus, were examined in their specific composition. Methods: Using high?performance thin?layer chromatography (HPTLC) for fingerprint analysis of different batches of herbal drugs and samples from various suppliers of Xanthii Fructus and Scrophulariae Radix were critically examined. The decoctions were prepared according to traditional rules, while the granules were dissolved in water in accordance with actual regulations. Furthermore, organic extracts of the plant material were examined and compared with aqueous extracts. Results: It could be demonstrated, that in some cases, there are remarkable differences in the specific composition between granules from different suppliers, the classical aqueous decoction and the organic extract used for the HPTLC fingerprinting. On the other hand, few examples exist for good comparability of decoctions and commercial granules. Conclusion: After critical evaluation of the above results, it can be questioned, if there is a so?called phytoequivalence between decoctions and commercial granules for prescription used in TCM practice.