High-sensitivity measurement of metastable ion abundances

✍ Scribed by F. W. McLafferty; J. Okamoto; H. Tsuyama; Y. Nakajima; T. Noda; H. W. Major

• Book ID: 102556828
• Publisher: John Wiley and Sons
• Year: 1969
• Tongue: English
• Weight: 190 KB
• Volume: 2
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/oms.1210020709

✦ Synopsis

Measurement of metastable ion abundances over a dynamic range of lo5 is possible with a specially designed m a s spectrometer. * See Ref. 1. .t Prototype of the commercially-available Hitachi RMH-2 m a s spectrometer.

* Thus the transitions 141'-+ 112+ through 145+ -+ 116' are found at m/e 89-0, 89.9, 90.9,91.8 and 92.8. The diffuse signal between the first two peaks is probably dueto 143+ 113+, rn/e 89.3, for which the optimum ESA focus value is 1.06% less than that used; the abundance of 143 + -113 + should be 2.2% of 142+ -f 113+.

t Another valuable use of the Major method is the identification of metastable transitions in the ordinary spectrum. Thus with the magnetic field set to focus an ordinary metastable, the ESA voltage is lowered until a peak appears; this voltage corresponds to mz/ml of the normal ESA potential.8