Prediction of chemical structure of aromatic hydrocarbons by pattern recognition of spectral lines obtained by fluorescence spectrometry in a supersonic jet

Lin, Cheng Huang

doi:10.1016/0039-9140(95)01536-k

Cited by 4 publications

(3 citation statements)

References 27 publications

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“…Compared to the gas phase, it is shifted by 66 cm −1 to the red. 36 Similar as for 9-CNA, the peaks assigned to the electronic origin and to a vibronic transition (not shown in Fig. 3) are accompanied by additional weak features shifted by 0.8, 2.1, and 3.6 cm −1 to the blue (cf.…”

Section: Resultssupporting

confidence: 54%

Helium induced fine structure in the electronic spectra of anthracene derivatives doped into superfluid helium nanodroplets

Pentlehner

Slenczka

2015

The Journal of Chemical Physics

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Electronic spectra of organic molecules doped into superfluid helium nanodroplets show characteristic features induced by the helium environment. Besides a solvent induced shift of the electronic transition frequency, in many cases, a spectral fine structure can be resolved for electronic and vibronic transitions which goes beyond the expected feature of a zero phonon line accompanied by a phonon wing as known from matrix isolation spectroscopy. The spectral shape of the zero phonon line and the helium induced phonon wing depends strongly on the dopant species. Phonon wings, for example, are reported ranging from single or multiple sharp transitions to broad (Δν > 100 cm(-1)) diffuse signals. Despite the large number of example spectra in the literature, a quantitative understanding of the helium induced fine structure of the zero phonon line and the phonon wing is missing. Our approach is a systematic investigation of related molecular compounds, which may help to shed light on this key feature of microsolvation in superfluid helium droplets. This paper is part of a comparative study of the helium induced fine structure observed in electronic spectra of anthracene derivatives with particular emphasis on a spectrally sharp multiplet splitting at the electronic origin. In addition to previously discussed species, 9-cyanoanthracene and 9-chloroanthracene will be presented in this study for the first time.

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Section: Resultssupporting

confidence: 54%

Helium induced fine structure in the electronic spectra of anthracene derivatives doped into superfluid helium nanodroplets

Pentlehner

Slenczka

2015

The Journal of Chemical Physics

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“…The pattern recognition provides a method for the prediction of chemical structure and can be applied to samples that have not previously been examined. 17 Indeed, when a complete mass database is available, a sample molecule can be accurately identified using the mass spectral data accumulated for a series of authentic compounds. However, without the derivation procedure, a mass spectrum of citrinin has not been reported by GC/MS.…”

Section: Precision: Ms Analysis By Pattern Recognitionmentioning

confidence: 99%

Simple and Sensitive Determination of Citrinin in Monascus by GC-Selected Ion Monitoring Mass Spectrometry

Shu

Lin

2002

ANAL. SCI.

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IntroductionCitrinin, a fungal metabolite, was first isolated from Penicillium citrinum in 1931 1 and has been detected as a natural contaminant of wheat, rye, barley, oat and Monascus. In fact, the mycotoxic citrinin is a secondary metabolite, which is produced by several fungal species of the genera Penicillium and Aspergillus. This mycotoxin, which could be present either naturally or artificially, at enhanced levels, may cause a public health problem, 2-5 such as the "yellowed rice" problem in Japan. Thus far, several TLC multi-mycotoxin methods have been proposed, but they exhibit relatively low sensitivities. [6][7][8] Reversed-phase HPLC methods with either UV absorbance or fluorescence detection have also been applied. [9][10][11] At this time, GC/MS is currently a reliable method of detection in many fields. However, the majority of mycotoxins are not volatile and must be derivatized in order to make them amenable to GC. 12 Even though several derivatization methods have been developed, this procedure is frequently time-consuming and is sometimes lacking in specificity.To overcome these limitations, a cold on-column injection technique coupled with GC/MS was developed for the direct analysis of metabolites produced by several Fusarium organisms without any chemical derivatization. 13In this study, we report on a new and highly sensitive method for the detection of citrinin in Monascus using GC-selected ion monitoring (SIM) mass spectrometry. This method, which does not require a derivatization procedure, was successfully applied to the analysis of citrinin in commercial Monascus products. Experimental Citrinin standard and reagentsCommercially pure citrinin [IUPAC: (3R,4S)-4,6-dihydro-8-hydroxy-3,4,5-trimethyl-6-oxo-3H-2-benzopyran-7-carboxylic acid] and chloroform (99 + %) were purchased from Sigma (St. Louis, MO, USA). Six commercial samples of Monascus red rice were acquired from various drugstores in Taipei, Taiwan. ApparatusA gas chromatograph (GC 5890 Hewlett-Packard, Avondale, PA, USA) equipped with a mass spectrometer (Hewlett-Packard 5973 mass selective detector) was used. A capillary column (30 m × 0.25 mm i.d.) with a piece of HP-5MS (cross-linked 5% PH ME siloxane) bonded stationary phase film 0.25 µm thickness (Agilent Technologies, USA) was used. The inlet temperature was maintained at 200˚C. The column oven was held at 70˚C for 3 min, then programmed from 70 -280˚C at 15˚C/min and, finally, held for 5 min. Helium carrier gas was used at a constant flow-rate of 1 mL/min without splitting mode. Data were collected using the Hewlett-Packard Chem-Station software. The mass spectrometric conditions were as follows: SIM mode; ionization energy, 12 eV; ion source temperature, 230˚C. The mass selective detector was operated in the SIM mode at a scan rate of 1.25 scans per second. Liquid-liquid extraction procedureMonascus samples were finely ground and 2 g of the resulting powder was extracted with 2 mL of chloroform. After 15 min of sonication and a 5 min centrifugation at 5000 rpm at room tempe...

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“…The error of the calculated energy is typically ±2 nm, which is, unfortunately, much larger than that of the experiment (±0.01 nm). An alternative approach is the use of a cross-correlation factor calculated between the sample and reference spectra to evaluate spectral similarity quantitatively [62]. The cross-correlation factors calculated between 2-ethylanthracene (sample) and anthracene derivatives (references) are listed in Table 1.…”

Section: T Imasaka Et Almentioning

confidence: 99%

Critical assessment: Use of supersonic jet spectrometry for complex mixture analysis (IUPAC Technical Report)

Imasaka¹,

Moore²,

Vo‐Dinh³

2003

Pure and Applied Chemistry

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Republication or reproduction of this report or its storage and/or dissemination by electronic means is permitted without theAbstract: When cooled to a temperature of a few K using supersonic jet expansion into a vacuum, a molecule exists in the lowest vibrational level of the ground electronic state and is isolated at collision-free conditions. The absorption or excitation/fluorescence spectrum is then greatly simplified, when transitions occur from this single vibrational level to a limited number of vibrational levels in the excited electronic state. This method, called supersonic jet spectrometry, is a powerful analytical technique because of its high selectivity, since the chemical species can be accurately identified and selectively quantified using the sharp spectral features even for large molecules. Supersonic jet spectrometry has distinct advantages over other low-temperature spectrometries, in that it can be combined with gas-phase separation and detection techniques such as chromatography or mass spectrometry. Therefore, this spectrometric technique can be used as a versatile analytical means, not only for basic research on pure substances, but also for practical trace analysis of chemical species in multicomponent samples (e.g., in biological monitoring or in environmental monitoring).

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Prediction of chemical structure of aromatic hydrocarbons by pattern recognition of spectral lines obtained by fluorescence spectrometry in a supersonic jet

Cited by 4 publications

References 27 publications

Helium induced fine structure in the electronic spectra of anthracene derivatives doped into superfluid helium nanodroplets

Helium induced fine structure in the electronic spectra of anthracene derivatives doped into superfluid helium nanodroplets

Simple and Sensitive Determination of Citrinin in Monascus by GC-Selected Ion Monitoring Mass Spectrometry

Critical assessment: Use of supersonic jet spectrometry for complex mixture analysis (IUPAC Technical Report)

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