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 : R. Graham Cooks (검색결과 5 건)
- 무료
- 기관 내 무료
- 유료
-
Differential Rapid Screening of Phytochemicals by Leaf Spray Mass Spectrometry
Muller, Thomas,Cooks, R. Graham Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.3
Ambient ionization can be achieved by generating an electrospray directly from plant tissue ("leaf spray"). The resulting mass spectra are characteristic of ionizable phytochemicals in the plant material. By subtracting the leaf spray spectra recorded from the petals of two hibiscus species H. moscheutos and H. syriacus one gains rapid access to the metabolites that differ most in the two petals. One such compound was identified as the sambubioside of quercitin (or delphinidin) while others are known flavones. Major interest centered on a $C_{19}H_{29}NO_5$ compound that occurs only in the large H. moscheutos bloom. Attempts were made to characterize this compound by mass spectrometry alone as a test of such an approach. This showed that the compound is an alkaloid, assigned to the polyhydroxylated pyrrolidine class, and bound via a $C_3$ hydrocarbon unit to a monoterpene.
-
Differential Rapid Screening of Phytochemicals by Leaf Spray Mass Spectrometry
Thomas Müller,R. Graham Cooks 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.3
Ambient ionization can be achieved by generating an electrospray directly from plant tissue (“leaf spray”). The resulting mass spectra are characteristic of ionizable phytochemicals in the plant material. By subtracting the leaf spray spectra recorded from the petals of two hibiscus species H. moscheutos and H. syriacus one gains rapid access to the metabolites that differ most in the two petals. One such compound was identified as the sambubioside of quercitin (or delphinidin) while others are known flavones. Major interest centered on a C19H29NO5 compound that occurs only in the large H. moscheutos bloom. Attempts were made to characterize this compound by mass spectrometry alone as a test of such an approach. This showed that the compound is an alkaloid, assigned to the polyhydroxylated pyrrolidine class, and bound via a C3 hydrocarbon unit to a monoterpene.
-
Jo, Sung-Chan,Augusti, Rodinei,Cooks, R. Graham Korean Society for Mass Spectrometry 2011 Mass spectrometry letters Vol.2 No.1
Hyperthermal ion/surface collisions of bromotoluene radical cations were studied using perfluorinated (F-SAM) and hydroxyl-terminated (OH-SAM) self-assembled monolayer surfaces in a tandem mass spectrometer with BEEQ geometry. The isomers were differentiated by ion abundance ratios taken from surface-induced dissociation (SID). The dissociation rate followed the order of ortho > meta > para isomers. The peak abundance ratio of m/z 51 to m/z 65 showed the best result to discern the isomers. A dissociation channel leading to tolylium ion was suggested to be responsible for the pronounced isomeric differences. The capability of SID to provide high-energy activation with narrow internal energy distribution may have channeled the reaction into the specific dissociation pathway, also facilitating small differences in reaction rates to be effective in the spectral time window of this experiment. All of the molecular ions experiencing reactive collisions with the F-SAM surface undergo transhalogenation, in which a fluorine atom on the surface replaces the bromine in the incoming ions. This reactive collision was dependent on the laboratory collision energy occurring in ca. 40.75 eV range.
-
Hyperthermal Collisions of Bromotoluene Molecular Cations at Self-Assembled Monolayer Surfaces
Sung-Chan Jo,Rodinei Augusti,R. Graham Cooks 사단법인 한국질량분석학회 2011 Mass spectrometry letters Vol.2 No.1
Hyperthermal ion/surface collisions of bromotoluene molecular ions were studied using perfluorinated (F-SAM) andhydroxyl-terminated (OH-SAM) self-assembled monolayer surfaces in a tandem mass spectrometer with BEEQ geometry. Theisomers were differentiated by ion abundance ratios taken from surface-induced dissociation (SID). The dissociation rate followedthe order of ortho>meta>para isomers. The peak abundance ratio of m/z 51 to m/z 65 showed the best result to discern theisomers, while the other ratios would effectively serve the same purpose as well. A dissociation channel leading to tolylium ionwas suggested to be responsible for the pronounced isomeric differentiability. The capability of SID to provide high-energy activationwith narrow internal energy distribution may have channeled the reaction into the specific dissociation pathway, also facilitatingsmall difference in reaction rates to be effective in the spectral time window of this experiment. All the molecular ions experiencedreactive collisions with the F-SAM surface leading to transhalogenation products, where a fluorine atom from the surface replacesthe bromine of the projectile. This reactive collision was dependant on the laboratory collision energy occurring in ca. 40~75 eV range.
-
Sung-chan Jo,Rodinei Augusti,R. Graham Cooks 한국질량분석학회 2011 Mass spectrometry letters Vol.2 No.1
Hyperthermal ion/surface collisions of bromotoluene radical cations were studied using perfluorinated (F-SAM) and hydroxyl-terminated (OH-SAM) self-assembled monolayer surfaces in a tandem mass spectrometer with BEEQ geometry. The isomers were differentiated by ion abundance ratios taken from surface-induced dissociation (SID). The dissociation rate followed the order of ortho > meta > para isomers. The peak abundance ratio of m/z 51 to m/z 65 showed the best result to discern the isomers. A dissociation channel leading to tolylium ion was suggested to be responsible for the pronounced isomeric differences. The capability of SID to provide high-energy activation with narrow internal energy distribution may have channeled the reaction into the specific dissociation pathway, also facilitating small differences in reaction rates to be effective in the spectral time window of this experiment. All of the molecular ions experiencing reactive collisions with the F-SAM surface undergo transhalogenation, in which a fluorine atom on the surface replaces the bromine in the incoming ions. This reactive collision was dependent on the laboratory collision energy occurring in ca. 40.75 eV range.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
