J. Mass Spectrom. Soc. Jpn. Vol. 57, No. 1, 2009 COMMENTARY Principles of the Delayed Extraction Technique 1 2 3, 4 Koichi T6C6@6, 1 Takaya S6ID=, 2 and Ken-ichi YDH=>CD 3, 4 1 Koichi Tanaka Mass Spectrometry Research Laboratory, Shimadzu Corporation, Kyoto, JAPAN 2 Advanced Technology Division, JEOL Ltd., Akishima, TOKYO, JAPAN 3 4 3 Biosignal Research Center, Organization of Advanced Science and Technology, and 4 The Integrated Center for Mass Spectrometry, Graduate School of Medicine, Kobe University, Kobe, JAPAN The delayed extraction (also known as pulsed extraction) technique involves the application of a time delay between the ionization pulse and an accelerating voltage pulse for desorption/ionization from a surface. This technique can achieve energy focusing in a matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometer and is used to improve mass resolving power. We explain the principles of delayed extraction (pulsed extraction) used in a MALDI TOF mass spectrometer. (Received December 1, 2008; Accepted December 5, 2008) 1. (delayed extraction, pulsed extraction) (matrix-assisted laser desorption/ionization: MALDI) ns (time-of-flight: TOF) (Fig. 1). (time-of-flight mass spectrometry: TOFMS) 1) #. 2), 3) 2. MALDI TOFMS (Fig. 2). (Sample Plate) (Ground) V 0 Fig. 2 v (1) qv 0 1 2 Mv2 (1) v 2V 0 q M 2V 0 q M q C M kg v m/s V 0 V (2) Correspondence to: Koichi T6C6@6, Koichi Tanaka Mass Spectrometry Research Laboratory, Shimadzu Corporation, 1Nishinokyo-Kuwabaracho, Nakagyo-ku, Kyoto 604 8511, JAPAN, e-mail: tanaka-ms@shimadzu.co.jp 604 8511 1 # 2007 7 29 MALDI-MS Technical Report 2, Pulsed Extraction 1) delayed extraction pulsed extraction 2 (IUPAC) Standard Definitions of Terms Relating to Mass Spectrometry 4) delayed extraction time-lag focusing Delayed extraction time-lag focusing 31
K. Tanaka, T. Satoh, & K. Yoshino Fig. 1. MALDI TOFMS (adrenocorticotropic hormone) fragment 18 39, [ACTH (13 39)]; Arg-Pro-Val-Lys-Val-Tyr-Pro- Asn-Gly-Ala-Glu-Asp-Glu-Ser-Ala-Glu-Ala-Phe- Pro-Leu-Glu-Phe; (MH ) 2465.20 Da. V 0 M kg q C (2) v specific charge q/m m/z M/q M/q q/m M/q (Drift Space) (Detector) M/q (m/z) m/z TOFMS 3. TOFMS TOFMS m/z TOF z, u m q z e, M m u M/q m/z e: 1.602 176 53 10 19 C 1 u: 1u 1.660 538 86 10 27 kg 12 C 1/12 ACTH: adrenocorticotropic hormone IUPAC: International Union of Pure and Applied Chemistry MALDI: matrixassisted laser desorption/ionization TOF: time-of-flight TOFMS: time-of-flight mass spectrometry Fig. 2. TOFMS 1 1 m/z TOFMS 2 Fig. 2 MALDI ev m/z TOFMS 4. TOFMS Continuous Extraction 32
Basics of the Delayed Extraction Technique Fig. 3. m/z 1 2 4.1 Fig. 3 Fig. 3A &B 33
K. Tanaka, T. Satoh, & K. Yoshino Fig. 4. I m/z 1 3 Fig. 3C m/z Fig. 3D (Extraction Ring) 34
Basics of the Delayed Extraction Technique Table 1. 2 MALDI TOFMS, m/z Fig. 5. II A) B) Sample Plate Extraction Ring Sample Plate t E C146-0197A, p. 5 Fig. 3A ns Fig. 3B m/z Fig. 3C m/z Fig. 3D TOFMS Table 1 4.2 MALDI ns Fig. 4 Fig. 35
K. Tanaka, T. Satoh, & K. Yoshino 5A Extraction Ring Extraction Ring Fig. 4 Fig. 5B 5. (m/z) m/z m/z m/z m/z m/z m/z 6. TOFMS, TOFMS kda TOFMS TOFMS 1) Pulsed Extraction MALDI- MS Technical Report No. 2, (2007). 2) J. Mass Spectrom. Soc. Jpn., 56, 49(2008). 3) Reflectron Mode MALDI-MS Technical Report No. 1, (2007). 4) K. K. Murray, R. K. Boyd, M. N. Eberlin, G. J. Langley, L. Li, and Y. Naito, Standard Definitions of Terms Relating to Mass Spectrometry (IUPAC Recommendations 2006), Draft, 31 Aug. 2006; p. 24; URL: http://old. iupac.org/reports/provisional/abstract06/murray prs. pdf. Keywords: Delayed extraction, Pulsed extraction, Time-offlight mass spectrometer, Matrix-assisted laser desorption/ ionization 36