A collision cell incorporating a curved r.f.-only quadrupole was constructed and evaluated in an experimental triple quadrupole mass spectrometer. The device was found to reduce the d.c. neutral-noise encountered in a liquid secondary ion mass spectrometry (SIMS)-type experiment by two orders of magnitude. The transmission of ions was not measurable changed. A theoretical discussion of the conditions under which the curved quadrupole will efficiently pass ions is provided. Some data from a new tandem quadrupole instrument with a curved r.f.-only quadrupole collision cell is given to illustrate the improved performance.

A new hybrid mass spectrometer of BEQQ geometry (B, magnetic sector; E, electric sector; Q, quadrupole mass filter) is described. The high resolution (BE) stage is interfaced to the double quadrupole (QQ) stage by a deceleration lens system (dual zoom lens with intermediate d.c. quadrupole) which also shapes the beam. The four reaction regions provide capabilities for both low- and high-energy MS/MS experiments, for exact mass measurements, and for sequential reactions in different regions. Provision is also made for energy and angle-resolved measurements which provide controlled energy deposition in selected ions. Needle collision cells are used in the first and third reaction regions. The r.f.-only quadrupole is encased in a gas-tight shroud and serves as a focussing device for collisions occurring in a laboratory energy range commonly 1–100 eV but sometimes considerably more. Capabilities are in place for recording parent, daughter and neutral species loss spectra associated with reactions in the collision quadrupole as well as the first and second field-free regions. High-resolution selection of the parent ions is possible. More complex scans are accessed through links between the electric and magnetic sector controls (provided by a linked scan microprocessor) and a system of microprocessors which controls the lens and quadrupole voltages.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNew scan modes accessed with a hybrid mass spectrometerJohn N. Louris, Larry G. Wright, R. Graham. Cooks, and Alan E. SchoenCite this: Anal. Chem. 1985, 57, 14, 2918–2924Publication Date (Print):December 1, 1985Publication History Published online1 May 2002Published inissue 1 December 1985https://pubs.acs.org/doi/10.1021/ac00291a039https://doi.org/10.1021/ac00291a039research-articleACS PublicationsRequest reuse permissionsArticle Views448Altmetric-Citations79LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

The BEQQ hybrid instrument provides capabilities for tandem mass spectrometry and for high resolution measurements. Reactions can be performed at energies between 5 and 3000 eV using any one of four reaction regions. Angle-resolved experiments allow control over the energy deposited upon collision. Processes which occur in sequence in different reaction regions are easily examined. The very large data domain is interrogated selectively. This involves the use of conventional parent, daughter and neutral species loss scans as well as new experiments in which the quadrupole is used to remove interferences in conventional linked scans and MIKES scans. Transmission data and data for efficiency of collision-induced dissociation are presented.

A new experimental arrangement for angle-resolved mass spectrometry is described featuring a needle which delivers collision gas to the source slit of a reversed geometry mass spectrometer. In this experiment the scattering angle is defined by pre-collision electrical deflection of the parent ion beam, as contrasted with post-collision selection of the direction of the daughter ion beam. Advantages are rapid access to any desired angle, coupled with an improvement in ion intensity and in angular resolution evident from measured breakdown curves. Collision-induced dissociation spectra of the methanol molecular ion, recorded over a range of scattering angles, agree well with previous results. Experiments which record ions that survive collisions, i.e., scatter without fragmentation, indicate that scattering of polyatomic ions through substantial angles (0–6°) makes a significant contribution to the phenomena underlying angle-resolved mass spectrometry.

Chemischer InformationsdienstVolume 13, Issue 21 Physical Organic Chemistry ChemInform Abstract: SILVER ION AFFINITIES OF ALCOHOLS AS ORDERED BY MASS SPECTROMETRY/MASS SPECTROMETRY S. A. MCLUCKEY, S. A. MCLUCKEYSearch for more papers by this authorA. E. SCHOEN, A. E. SCHOENSearch for more papers by this authorR. G. COOKS, R. G. COOKSSearch for more papers by this author S. A. MCLUCKEY, S. A. MCLUCKEYSearch for more papers by this authorA. E. SCHOEN, A. E. SCHOENSearch for more papers by this authorR. G. COOKS, R. G. COOKSSearch for more papers by this author First published: May 25, 1982 https://doi.org/10.1002/chin.198221051AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume13, Issue21May 25, 1982 RelatedInformation

Chemischer InformationsdienstVolume 12, Issue 25 Physical Organic Chemistry ChemInform Abstract: LASER-DESORPTION MASS SPECTROMETRY/MASS SPECTROMETRY AND THE MECHANISM OF DESORPTION IONIZATION D. ZAKETT, D. ZAKETTSearch for more papers by this authorA. E. SCHOEN, A. E. SCHOENSearch for more papers by this authorR. G. COOKS, R. G. COOKSSearch for more papers by this authorP. H. HEMBERGER, P. H. HEMBERGERSearch for more papers by this author D. ZAKETT, D. ZAKETTSearch for more papers by this authorA. E. SCHOEN, A. E. SCHOENSearch for more papers by this authorR. G. COOKS, R. G. COOKSSearch for more papers by this authorP. H. HEMBERGER, P. H. HEMBERGERSearch for more papers by this author First published: June 23, 1981 https://doi.org/10.1002/chin.198125067AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume12, Issue25June 23, 1981 RelatedInformation

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIdentification of modified nucleosides by secondary-ion and laser-desorption mass spectrometrySteve E. Unger, Alan E. Schoen, R. Graham Cooks, Dennis J. Ashworth, Jose DaSilva Gomes, and Ching-Jer ChangCite this: J. Org. Chem. 1981, 46, 23, 4765–4769Publication Date (Print):November 1, 1981Publication History Published online1 May 2002Published inissue 1 November 1981https://pubs.acs.org/doi/10.1021/jo00336a028https://doi.org/10.1021/jo00336a028research-articleACS PublicationsRequest reuse permissionsArticle Views90Altmetric-Citations25LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

AbstractDie neue Methode besteht darin, daß rechnergestützt nur diejenigen peaks im MS aufgezeichnet werden, die zu einer bestimmten, stoßinduzierten Reaktion m1+ → m2+ + m3 bzw. m1‐ → m2‐ + m3 gehören.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSelected fragment scans of mass spectrometers in direct mixture analysisD. Zakett, A. E. Schoen, R. W. Kondrat, and R. G. CooksCite this: J. Am. Chem. Soc. 1979, 101, 22, 6781–6783Publication Date (Print):October 1, 1979Publication History Published online1 May 2002Published inissue 1 October 1979https://pubs.acs.org/doi/10.1021/ja00516a064https://doi.org/10.1021/ja00516a064research-articleACS PublicationsRequest reuse permissionsArticle Views79Altmetric-Citations32LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Pyrolysis of DNA into a chemical ionization source yields protonated bases and other base-containing ions. Kinetic energy spectra allow the characterization of the bases 5-methylcytosine and 1-methyladenine from underivatized salmon sperm DNA. Isomeric bases are distinguishable with this technique.