본문 바로가기
HOME> 저널/프로시딩 > 저널/프로시딩 검색상세

저널/프로시딩 상세정보

권호별목차 / 소장처보기

H : 소장처정보

T : 목차정보

Journal of the American Society for Mass Spectrome...Journal of the American Society for Mass Spectrometry 13건

  1. [해외논문]   Open access atmospheric pressure chemical ionization mass spectrometry for routine sample analysis  

    Taylor, L.C.E. ; Johnson, R.L. ; Raso, R.
    Journal of the American Society for Mass Spectrometry v.6 no.5 ,pp. 387 - 393 , 1995 , 1044-0305 ,

    초록

    We report the introduction and use of an atmospheric pressure chemical ionization liquid chromatography-mass spectrometry instrument that has been designed specifically for use by the synthetic chemist on an open access, walk-in basis. This instrument has been configured with an easy-to-use sample log-in terminal that requires the user to provide only a sample identification number and a user name. Sample analysis takes approximately 4 min and provides the synthetic and medicinal chemist with rapid and reliable mass spectrometry analysis. Since installation of the system, it has analyzed an average of about 80 samples per day and has the capacity to run over 100 samples per day without the intervention of a specialist operator. This capability has eliminated the need for an operator to analyze routine samples and allows the mass spectroscopist more time to deal with problem solving.

    원문보기

    원문보기
    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  2. [해외논문]   Putting mass spectrometry in the hands of the end user  

    Pullen, F.S. ; Perkins, G.L. ; Burton, K.I. ; Ware, R.S. ; Teague, M.S. ; Kiplinger, J.P.
    Journal of the American Society for Mass Spectrometry v.6 no.5 ,pp. 394 - 399 , 1995 , 1044-0305 ,

    초록

    The ease of use of the newer liquid chromatography-mass spectrometry interfaces has made possible the automated acquisition of spectra from large batch queues of samples. This fact, combined with the realization that unit molecular mass determination was the only datum desired by a majority of drug discovery synthetic chemists, led us to develop open access mass spectrometry in the early 1990s. Open access spectrometers now scan over 100,000 samples per year from synthesis laboratories at Pfizer. Our experiences with this novel use of mass spectrometry in a large research facility are discussed and we detail some of the pitfalls we believe to be common to this approach. In addition, we offer some reflection on the cultural changes we have observed in our research environment since this experiment began.

    원문보기

    원문보기
    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  3. [해외논문]   An inductively coupled plasma-time-of-flight mass spectrometer for elemental analysis. Part II: Direct current quadrupole lens system for improved performance  

    Myers, D.P. ; Li, G. ; Mahoney, P.P. ; Hieftje, G.M.
    Journal of the American Society for Mass Spectrometry v.6 no.5 ,pp. 400 - 410 , 1995 , 1044-0305 ,

    초록

    An electrostatic quadrupole lens has been substituted for a cylindrical lens system used in the original inductively coupled plasma-time-of-flight mass spectrometer (ICP-TOFMS). With an improved vacuum system also installed, the cylindrical and quadrupole lenses are compared to each other and to the performance of the prototype ICP-TOFMS. The quadrupole lens requires no tradeoff between ion throughput and resolving power as was encountered with cylindrical lenses. The background noise in both ion-optical systems is within the same order of magnitude. Images of the ion beam formed by each ion-optical system have been obtained on a microchannel plate-phosphor screen. The quadrupole lens shows a higher ion-beam flux and produces a slitlike focus required in the orthogonal ICP-TOFMS instrument. Signal-to-noise ratios in the ICP-TOFMS can be improved by using a technique called pulsed-ion injection that is particularly convenient with the quadrupole lens. In this technique, one quadrupole electrode is pulsed to prevent ions from entering the extraction zone except when an ion packet is to be extracted for mass analysis. This technique significantly reduces the noise over continuous ion injection. In the orthogonal ICP-TOFMS with pulsed-ion injection, 0.5 frnol of analyte could be detected in 1.4 ms with a proper data acquisition system. Overall, the combination of a quadrupole lens and pulsed-ion injection may provide detection limits for the ICP-TOFMS that are competitive with those of quadrupole inductively coupled plasma-mass spectrometry instruments.

    원문보기

    원문보기
    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  4. [해외논문]   An inductively coupled plasma-time-of-flight mass spectrometer for elemental analysis. Part III: Analytical performance  

    Myers, D.P. ; Li, G. ; Mahoney, P.P. ; Hieftje, G.M.
    Journal of the American Society for Mass Spectrometry v.6 no.5 ,pp. 411 - 420 , 1995 , 1044-0305 ,

    초록

    A time-of-flight mass spectrometer (TOFMS) was evaluated as a mass analyzer for inductively coupled plasma mass spectrometry (ICP-MS). The long-term drift of signals was in the range of 7-8% relative standard deviation, whereas the short-term precision was between 5 and 20%, somewhat worse than is typically reported for commercial ICP-MS instruments (5%). However, precision can be improved considerably in the TOFMS by ratioing isotopic peaks or through internal standardization, a consequence of its ability to extract all measured ions simultaneously from the inductively coupled plasma. This feature was demonstrated by monitoring the 206 Pb/ 208 Pb ratio with boxcar averagers. In this ratioing mode, precision was improved to approximately 0.5%. Detection limits were measured with two alternative signal processing systems: (1) discriminator-gated integration and (2) integration of digitized spectra. Both methods improved the signal-to-noise ratio by a factor of from 10 to 100, although detection limits were still 1-2 orders of magnitude poorer for most elements than from the best commercial ICP-MS instruments. The dynamic range of the discriminator-gated integration system is over 4 orders of magnitude, but can be extended to 10 6 with planned increases in primary ion-beam current, which is currently 10-100 times lower than is found in other instruments. Virtually simultaneous multielement and multiisotope analysis is possible for masses from 7 Li to 209 Bi with minimal mass bias and detection limits on the 0.4-2-ppb level.

    원문보기

    원문보기
    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  5. [해외논문]   Nitrogen Trifluoride: A New Reactant Gas in Chemical Reaction Interface Mass Spectrometry for Detection of Phosphorus, Deuterium, Chlorine, and Sulfur  

    Song, H. ; Abramson, F.
    Journal of the American Society for Mass Spectrometry v.6 no.5 ,pp. 421 - 427 , 1995 , 1044-0305 ,

    초록

    A new set of reactions that involve fluorine have been investigated in chemical reaction interface mass spectrometry (CRIMS). The primary goal of this study was to provide a means to selectively detect phosphorus-containing compounds, which fluorine does by generating PF 5 . PF 4 + , the main fragment ion of PF 5 , provides a sensitive (10 pg/s), selective, and linear (> 10 5 dynamic range) channel for phosphorus-containing analytes. This fluorine-rich environment also provides new ways to selectively and simultaneously detect hydrogen isotopes, chlorine, and sulfur. NF 3 as a reactant gas provides the most comprehensive array of elemental and isotopic detection yet available for CRIMS. An application of phosphorus-selective detection was attempted by examination of a plasma sample from a patient who had been treated with cyclophosphamide. The phosphorus-selective channel showed six peaks: one is derivatized phosphate, two are t-butyldimethylsilyl (TBDMS) derivatives of cyclophosphamide, another two are TBDMS derivatives of 4-hydroxy-yclophosphamide, and one is from underivatized cyclophosphamide. The simultaneous detection of chlorinecontaining compounds confirmed our results for those peaks related to cyclophosphamide and its metabolite.

    원문보기

    원문보기
    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  6. [해외논문]   Comparison of charged derivatives for high energy collision-induced dissociation tandem mass spectrometry  

    Zaia, J. ; Biemann, K.
    Journal of the American Society for Mass Spectrometry v.6 no.5 ,pp. 428 - 436 , 1995 , 1044-0305 ,

    초록

    Fixed-charge derivatives have been used to direct the fragmentation pattern of high energy collision-induced dissociation tandem mass spectra for several years. It has been noted that a fixed-charge placed at a terminus of a peptide will simplify the pattern of fragment ions that are produced in collision-induced dissociation. Trimethylammoniumacetyl, dimethyloctylammoniumacetyl, and triphenylphosphoniumethyl derivatives have been cited in the literature for this purpose and many other structures are possible. This work compares the cited derivatives as well as some new structures. The criteria used include the ease of synthesis and purification of the derivatized peptide and the effects of the derivative on the peptide sequence fragment ion yield and ionization efficiency. The trimethylammoniumacetyl derivative is concluded to be the most practical for general use, whereas the dimethyloctylammoniumacetyl derivative is found to be desirable for use with hydrophilic peptides.

    원문보기

    원문보기
    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  7. [해외논문]   False positives and the detection of cyclodextrin inclusion complexes by electrospray mass spectrometry  

    Cunniff, J.B. ; Vouros, P.
    Journal of the American Society for Mass Spectrometry v.6 no.5 ,pp. 437 - 447 , 1995 , 1044-0305 ,

    초록

    The results of previous works that have claimed to detect cyclodextrin inclusion complexes via the ''soft'' ionization technique of electrospray ionization mass spectrometry are revisited. A more extensive study of cyclodextrin mixtures with amino acids and small peptides demonstrates that amino acid and peptide ''complexes'' are detected by electrospray mass spectrometry regardless of the presence (or not) of an aromatic moiety on the side chain. Amino acids that may be least likely to form hydrophobic inclusion complexes with cyclodextrin in solution generally show the most intense complex ions. The data suggest that these ''complexes'' are, in all likelihood, electrostatic adducts formed during the electrospray process. Systematic controls are suggested to ensure that ''false positives'' do not negate many of the claims concerning the detection of solution-derived noncovalent compounds.

    원문보기

    원문보기
    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  8. [해외논문]   Simplified application of quadrupolar excitation in Fourier transform ion cyclotron resonance mass spectrometry  

    Hendrickson, C.L. ; Drader, J.J. ; Laude, D.A.
    Journal of the American Society for Mass Spectrometry v.6 no.5 ,pp. 448 - 452 , 1995 , 1044-0305 ,

    초록

    A new method for application of quadrupolar excitation to the trapped ion cell of a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer is presented. Quadrupolar excitation is conventionally applied to the two pairs of opposed electrodes that normally perform the excitation and detection functions in the FTICR experiment. Symmetry arguments and numerically calculated isopotential contours within the trapped ion cell lead to the conclusion that quadrupolar excitation can be applied to a single pair of opposed side electrodes. Examples of effective quadrupolar axialization via this method include a sevenfold signal-to-noise enhancement derived from 50 remeasurements of a single population of trapped bovine insulin ions and the selective isolation of a single charge state of horse heart myoglobin after an initial measurement that revealed the presence of 14 charge states.

    원문보기

    원문보기
    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  9. [해외논문]   Book review  

    Weintraub, S.T.
    Journal of the American Society for Mass Spectrometry v.6 no.5 ,pp. 453 , 1995 , 1044-0305 ,

    초록

    A new method for application of quadrupolar excitation to the trapped ion cell of a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer is presented. Quadrupolar excitation is conventionally applied to the two pairs of opposed electrodes that normally perform the excitation and detection functions in the FTICR experiment. Symmetry arguments and numerically calculated isopotential contours within the trapped ion cell lead to the conclusion that quadrupolar excitation can be applied to a single pair of opposed side electrodes. Examples of effective quadrupolar axialization via this method include a sevenfold signal-to-noise enhancement derived from 50 remeasurements of a single population of trapped bovine insulin ions and the selective isolation of a single charge state of horse heart myoglobin after an initial measurement that revealed the presence of 14 charge states.

    원문보기

    원문보기
    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  10. [해외논문]   ASMS news  


    Journal of the American Society for Mass Spectrometry v.6 no.5 ,pp. 454 - 457 , 1995 , 1044-0305 ,

    초록

    A new method for application of quadrupolar excitation to the trapped ion cell of a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer is presented. Quadrupolar excitation is conventionally applied to the two pairs of opposed electrodes that normally perform the excitation and detection functions in the FTICR experiment. Symmetry arguments and numerically calculated isopotential contours within the trapped ion cell lead to the conclusion that quadrupolar excitation can be applied to a single pair of opposed side electrodes. Examples of effective quadrupolar axialization via this method include a sevenfold signal-to-noise enhancement derived from 50 remeasurements of a single population of trapped bovine insulin ions and the selective isolation of a single charge state of horse heart myoglobin after an initial measurement that revealed the presence of 14 charge states.

    원문보기

    원문보기
    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지

논문관련 이미지