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  • P-ISSN2233-4203
  • E-ISSN2093-8950
Search Word: ion-trap, Search Result: 12
1
Sarkhosh Seddighi Chaharborj(Universiti Purta Malaysia) ; Seyyed Mahmod Sadat Kiai(Universiti Purta Malaysia) ; Norihan Md Arifin(Universiti Purta Malaysia) ; Yousof Gheisari(Universiti Purta Malaysia) 2015, Vol.6, No.3, pp.59-64 https://doi.org/10.5478/MSL.2015.6.3.59
초록보기
Abstract

Quadrupole ion trap mass analyzer with a simplified geometry, namely, the cylindrical ion trap (CIT), has been shown to be well-suited using in miniature mass spectrometry and even in mass spectrometer arrays. Computation of stability regions is of particular importance in designing and assembling an ion trap. However, solving CIT equations are rather more dif- ficult and complex than QIT equations, so, analytical and matrix methods have been widely used to calculate the stability regions. In this article we present the results of numerical simulations of the physical properties and the fractional mass resolu- tions of the confined ions in the first stability region was analyzed by the fifth order Runge-Kutta method (RKM5) at the optimum radius size for both ion traps. Because of similarity the both results, having determining the optimum radius, we can make much easier to design CIT. Also, the simulated results has been performed a high precision in the resolution of trapped ions at the optimum radius size.

2
Sarkhosh Seddighi Chaharborj(Universiti Putra Malaysia) ; Seyyed Mahmod Sadat Kiai(Plasma Physics and Nuclear Fusion Resea) ; Norihan Md Arifina(Universiti Putra Malaysia) ; Yousof Gheisari(Islamic Azad University) 2015, Vol.6, No.4, pp.91-98 https://doi.org/10.5478/MSL.2015.6.4.91
초록보기
Abstract

The Brownian motion or Wiener process, as the physical model of the stochastic procedure, is observed as an indexed collection random variables. Stochastic procedure are quite influential on the confinement potential fluctuation in the quadrupole ion trap (QIT). Such effect is investigated for a high fractional mass resolution spectrometry. A stochastic procedure like the Wiener or Brownian processes are potentially used in quadrupole ion traps (QIT). Issue examined are the sta-bility diagrams for noise coefficient, as well as ion trajectories in real time for noise coefficient, . The simulated results have been obtained with a high precision for the resolution of trapped ions. Furthermore, in the lower mass range, the impulse voltage including the stochastic potential can be considered quite suitable for the quadrupole ion trap with a higher mass resolution.

3
L. Karimi(Department of Chemistry, University of Zanjan) ; S.M. Sadat Kiai(Nuclear Science and Technology Research Institute (NSTR)) ; A. R. babazaheh(Department of Chemistry, University of Zanjan) ; M. Elahi(Nuclear Science and Technology Research Institute (NSTR)) ; S. R. Shafaei(Nuclear Science and Technology Research Institute (NSTR)) 2019, Vol.10, No.1, pp.27-31 https://doi.org/10.5478/MSL.2019.10.1.27
초록보기
Abstract

In this article, the properties of CO 2 + (CO 2 ) n clusters in a Paul ion trap have been investigated using mass-selective instability mode which conducted by chosen precursor ions, mainly Ar + and CO 2 + produced by a mixture of Ar and CO 2 . Expo- sure of CO 2 + ions to CO 2 molecules, lead to the formation of CO 2 + (CO 2 ) n clusters. Here, Ar gas react as a buffer gas and lead to form CO 2 + (CO 2 ) n cluster by collisional effect.

4
S. M. Sadat Kiai(Nuclear Science and Technology Research) ; M. Elahi S. Adlparvar(Nuclear Science and Technology Research) ; N. Nemati S. R. Shafaei(Nuclear Science and Technology Research) ; Leila Karimi(University of Zanjan) 2015, Vol.6, No.4, pp.112-115 https://doi.org/10.5478/MSL.2015.6.4.112
초록보기
Abstract

In this article, we examine the influences of Ne and He buffer gases under confined Ar + ion cloud in a homemade Paul ion trap in various pressures and confinement times. The trap is of small size (r 0 = 1 cm) operating in a radio frequency (rf) voltage only mode, and has limited accuracy of 13 V. The electron impact and ionization process take place inside the trap and a Faraday cup has been used for the detection. Although the experimental results show that the Ar + ion FWHM with Ne buffer gas is wider than the He buffer gas at the same pressure (1×10 -1 mbar) and confinement time is about 1000 µs, nevertheless, a faster cooling was found with He buffer gas with 500 µs. ultimetly, the obtanied results performed an average cloud tempertures reduced from 1777 K to 448.3 K for Ne (1000 µs) and from 1787.9 K to 469.4 K for He (500 µs)

5
Young Jin Lee(Iowa State University, Ames Laboratory) ; Erica A. Smith(Iowa State University, Ames Laboratory) ; Ji Hyun Jun(Iowa State University, Ames Laboratory) 2012, Vol.3, No.2, pp.29-38 https://doi.org/10.5478/MSL.2012.3.2.29
초록보기
Abstract

A new approach of volatile compounds analysis is proposed using a linear ion trap Orbitrap mass spectrometer coupledwith gas chromatography through an atmospheric pressure photoionization interface. In the proposed GC-HRMS/MSapproach, direct chemical composition analysis is made for the precursor ions in high resolution MS spectra and the structuralidentifications were made through the database search of high quality MS/MS spectra. Successful analysis of a complex perfumesample was demonstrated and compared with GC-EI-Q and GC-EI-TOF. The current approach is complementary to conventionalGC-EI-MS analysis and can identify low abundance co-eluting compounds. Toluene co-sprayed as a dopant through APIprobe significantly enhanced ionization of certain compounds and reduced oxidation during the ionization.

초록보기
Abstract

An advanced and reliable high performance liquid chromatography (HPLC)/ultraviolet detector (UV)/ion-trap timeof-flight (IT-TOF) mass spectrometry was developed for the simultaneous quantification of 19 marker compounds in Bangpoong-tong-sung-san (BPTS), a traditional oriental prescription. Various parameters affecting HPLC separation and IT-TOFdetection were investigated, and optimized conditions were identified. The separation was achieved on a Capcell PAK C18 column(1.5 mm × 250 mm, 5 μm particle size) using a gradient elution of acetonitrile and water containing 0.1% formic acid at aflow rate of 0.1 mL/min. The column temperature was maintained at 40oC and the injection volume was 2 μL. IT-TOF systemwas equipped with an electrospray ion source (ESI) operating in positive or negative ion mode. The optimized electrospray ionizationparameters were as follows: ion spray voltage, +4.5 kV (positive ion mode), or -3.5 kV (negative ion mode); drying gas(N2), 1.5 L/min; heat block temperature, 200oC. Automatic MSn (n = 1~3) analyses were carried out to obtain structural informationof analytes. Elemental compositions and their mass errors were calculated based on their accurate masses obtained from aformula predictor software. The marker compounds in BPTS were identified by comparisons between MSn spectra from standardsand those from extracts. Moreover, the libraries of MS2 and MS3 spectra and accurate masses of parent and fragment ionsfor marker compounds were constructed. The developed method was successfully applied to the BPTS extracts and identified 17out of 19 marker compounds in the BPTS extracts.

7
Sangeetha Ramachandran(Cochin University of Science and technology) ; Tessamma Thomas(Cochin University of Science and technology) 2019, Vol.10, No.2, pp.50-55 https://doi.org/10.5478/MSL.2019.10.2.50
초록보기
Abstract

The fragmentation statistics of ion trap CID (Collision-Induced Dissociation) spectra using 87,661 tandem mass spectra of doubly charged tryptic peptides are analyzed here. In contrast to the usual method of using intensity information, the frequency of occurrence of fragment ions, with respect to the position of the cleavage site and the residues at these sites is stud-ied in this paper. The analysis shows that the frequency of occurrence of fragment ion peaks is more towards the middle of the peptide than its ends. It was noted that amino acid with an aromatic and basic side chain at N- & C- terminal end of the peptide stimulates more peaks at the lower end of the spectrum. The residue pair effect was shown when the amide bond occurs between acidic and basic residues. The fragmentation at these sites (D/E-H/R/K) stimulates the generation of the y-ion peak. Also, the cleavage site H–H/R/K stimulates the generation of b-ions. K-P environment in the peptide sequence has more tendency to gen-erate y-ions than b-ions. Statistical analysis helps in the visualization of the CID fragmentation pattern. Cleavage pattern along the length of the peptide and the residue pair effects, enhance the knowledge of fragmentation behavior, which is useful for the better interpretation of tandem mass spectra.

8
A. F. M. Motiur Rahman(King Saud University) ; Mohamed W. Attwa(King Saud University) ; Pervez Ahmad(King Saud University) ; Mohammad Baseeruddin(King Saud University) ; Adnan A. Kadi(King Saud University) 2013, Vol.4, No.2, pp.30-33 https://doi.org/10.5478/MSL.2013.4.2.30
초록보기
Abstract

Chalcones are naturally occurring, biologically active molecules generating interest from a wide range of researchapplications including synthetic methodology development, biological activity investigation and studying fragmentation patterns. Inthis article, a series of chalcones has been synthesized and their fragmentation behavior was studied using modern ambient ionizationtechnique Direct Analysis in Real Time (DART). DART ion source connected with an ion trap mass spectrometer wasused for the fragmentation of various substituted chalcones. The chalcones were introduced to the DART source using a glasscapillary without sample preparation step. All the chalcones showed prominent molecular ion peaks [M]•+ corresponding to thestructures. Multistage mass spectral data MSn (MS2 and MS3) were collected for all the chalcones studied. The chalcones withsubstitutions at 3, 4 or 5 positions gave product ion peaks with the loss of a phenyl radical (Ph•) by radical initiated α-cleavage,while substitution at 2 position of chalcone in the A-ring gave a product ion peak with the loss of substituted styryl radical(PhCH = CH•). In case of the chalcones with the substituent at 4 positions in A and B rings gave both types of fragmentation patterns. In conclusion, chalcones can be easily characterized using modern DART interface in very short time and efficientlywithout any cumbersome sample pretreatment.

9
Unyong Kim(Chung-Ang university, Korea institute of Science and Technology) ; Sang Beom Han(Chung-Ang university) ; Oh-Seung Kwon(Korea Institute of Science and Technology) ; Hye Hyun Yoo(Hanyang University) 2011, Vol.2, No.1, pp.20-23 https://doi.org/10.5478/MSL.2011.2.1.020
초록보기
Abstract

The purpose of this study is to investigate the in vitro metabolism of hesperetin, a bioflavonoid. Hesperetin was incubatedwith rat liver microsomes in the presence of NADPH and UDP-glucuronic acid for 30 min. The reaction mixture was analyzedby liquid chromatography-ion trap mass spectrometer and the chemical structures of hesperetin metabolites were characterzed basedon their MS/MS spectra. As a result, a total of five metabolites were detected in rat liver microsomes. The metabolites were identifiedas a demethylated metabolite (eriodictyol), two hesperetin glucuronides, and two eriodictyol glucuronides.

10
Bruna R. deLima(Federal University of Amazonas) ; Felipe M. A. da Silva(Federal University of Amazonas) ; Hector H. F. Koolen(Federal University of Amazonas) ; Richardson A. de Almeida(Federal University of Amazonas) ; Afonso D. L. de Souza(Federal University of Amazonas) 2014, Vol.5, No.4, pp.115-119 https://doi.org/10.5478/MSL.2014.5.4.115
초록보기
Abstract

The Brazil nut (Bertholletia excelsa - Lecythidaceae) is considered a product with high economic value, being a food widely appreciated for its nutritional qualities. Although previous studies have reported the biochemical composition of Brazil nut oil, the knowledge regarding the phospholipid composition exhibits a disagreement: the composition of fatty acids present in the structures of phospholipids is reported as being different from the composition of the free fatty acids present in the oil. In this work, solid phase extraction (SPE) was employed to provide a fast extraction of the phospholipids from Brazil nuts, in order to compare the phospholipid profile of the in nature nuts and their fatty acids precursor present in the oil. The major phospholipids were characterized by mass spectrometry approach. Their fragmentation pattern through direct infusion electrospray ionization ion-trap tandem mass spectrometry (ESI-IT-MS2) proved to be useful to unequivocal characterization of these substances. High resolution (HR) experiments through ESI using a quadruple time of flight mass spectrometry (QTOF) system were performed to reinforce the identifications.

Mass Spectrometry Letters