http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Marriott, Philip J (검색결과 5 건)
- 무료
- 기관 내 무료
- 유료
-
-
-
Park, Hae Eun,Lee, Seok-Young,Hyun, Sun-Hee,Kim, Da Yeon,Marriott, Philip J,Choi, Hyung-Kyoon Oxford University Press 2013 Journal of AOAC International Vol.96 No.6
<B>Abstract</B><P>Ginseng roots are an important herbal resource worldwide, and the adulteration of ginseng with age is recognized as a serious problem. It is therefore crucial to develop objective criteria or standard protocols for differentiating ginseng root samples according to their cultivation age. The reported study used GC/MS combined with multivariate statistical analysis with variable selection to obtain metabolic profiling and an optimal partial least squares-discriminant analysis (PLS-DA) model for the differentiation of ginseng according to cultivation age. Relative levels of various metabolites, such as amino acids, alcohols, fatty acids, organic acids, and sugars, were measured for various ginseng cultivation ages. Increasing cultivation age resulted in the production of higher levels of panaxynol and panaxydol, which are active polyacetylene compounds in ginseng. In addition, optimized PLS-DA models for the prediction of ginseng age were obtained by selecting variables based on a variable importance in the projection cut-off value of 1.3. Proline, glucaric acid, mannose, gluconic acid, glucuronic acid, myoinositol, panaxydol, and panaxynol are suggested as key and relevant compounds with which to differentiate the age of ginseng samples. The findings of this study suggest that GC/MS-based metabolic profiling can be used to differentiate ginseng samples according to cultivation age.</P>
-
Mitrevski, B.,Webster, R.L.,Rawson, P.,Evans, D.J.,Choi, H.K.,Marriott, P.J. Elsevier 2012 Journal of chromatography Vol.1224 No.-
To characterize a fuel's thermal and storage stability an understanding of the process of oxidation and oxidation pathways is essential. Oxidation pathways commence with hydroperoxides which quickly decompose to form a range of alcohols, acids and other oxygen-containing species. In the presence of significant levels of hydrocarbon-based matrix, analysis of these heteroatomic species is difficult. Applying multidimensional gas chromatography with very narrow heart-cut windows (0.20min) minimizes the number of compounds transferred to the second dimension (<SUP>2</SUP>D) column during each heart-cut. Successive heart-cuts every 2.00min are taken throughout the analytical run, since each heart-cut has a maximum retention on <SUP>2</SUP>D of <2.00min on the fast elution <SUP>2</SUP>D column. Subsequent analyses involve incrementing or offsetting the heart-cut windows by 0.20min, so after 10 analyses, a complete coverage of the sample components can be obtained. On the polar <SUP>1</SUP>D and non-polar <SUP>2</SUP>D phase column arrangement, non-polar matrix compounds elute last on the <SUP>2</SUP>D column, and this determines the largest <SUP>2</SUP>t<SUB>R</SUB>; i.e. <SUP>2</SUP>t<SUB>R</SUB><P<SUB>M</SUB> to ensure retained components on <SUP>2</SUP>D will not overlap with subsequent heart-cuts. Heartcutting is supported by cryotrapping at the start of the <SUP>2</SUP>D column in order to provide significantly better resolution. Good quality MS library match data generally demonstrate the high resolution separation of oxygenates achieved. Whilst 1D GC-MS was unsuccessful in identifying any of the oxygen-containing compounds reported here, good correlation of MS data (with average MS library similarity data) for acids (903), alcohols (909), ketones (941) and aldehydes (938) in the sample is obtained. The method requires ten sequential runs, and this can be accomplished automatically once the events table is set up. However if fewer target compounds are to be transferred, a reduced number of sequential runs can be implemented.
-
Yang, Seung-Ok,Kim, Yujin,Kim, Hee-su,Hyun, Sun-Hee,Kim, So-Hyun,Choi, Hyung-Kyoon,Marriott, Philip J. Elsevier 2011 Journal of chromatography A Vol.1218 No.18
<P><B>Abstract</B></P><P>A method for separation and identification of peaks in essential oil samples based on rapid repetitive heart-cutting using multidimensional gas chromatography (MDGC)–mass spectrometry (MS) coupled with a cryotrapping interface is described. Lavender essential oil is analyzed by employing repetitive heart-cut intervals of 1.00 and 1.50min, achieved in a parallel MDGC–MS/GC-FID experiment. The number of peaks that were detected in 1D GC operation above a given response threshold more than tripled when MDGC–MS employing the cryotrapping module method was used. In addition, MDGC–MS enabled detection of peaks that were not individually evident in 1D GC–MS, owing to effective deconvolution in time of previously overlapped peaks in 1D GC. Thus separation using the cryomodulation approach, without recourse to using deconvolution software, was possible. Peaks widths decreased by about 5–7-fold with the described method, peak capacity increased from about 9 per min to 60 per min, and greater sensitivity results. Repeatability of retention times for replicate analyses in the multidimensional mode was better than 0.02% RSD. The present study suggests that the described heart-cutting technique using MDGC–MS can be used for general improvement in separation and identification of volatile compounds.</P>
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
