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Properties and Applications of an RF-only Hexapole Collision Cell in ICP Mass Spectrometry. J. Speakman, P.J. Turner, R.C.Haines, T.O.Merren, A.N. Eaton, J. Letcher. +. The Problem: Argide Interferences. 100. %. 0. 50. 60. Collision cell’s are used on Organic instruments
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Properties and Applications of an RF-only Hexapole Collision Cell in ICP Mass Spectrometry J. Speakman, P.J. Turner, R.C.Haines, T.O.Merren, A.N. Eaton, J. Letcher
+ The Problem: Argide Interferences 100 % 0 50 60
Collision cell’s are used on Organic instruments for MS-MS Purpose is to fragment & ‘thermalise’ ions
100 Conventional ICP-MS blank spectrum % 0 50 60
100 ICP-HEX-MS blank spectrum % 0 50 60
100 ICP-HEX-MS 10ppb Fe & Co % 0 50 60
100 ICP-HEX-MS blank spectrum ICP-HEX-MS 10ppb Fe & Co % 0 50 60
100 Conventional ICP-MS blank spectrum ICP-HEX-MS blank spectrum % 0 50 60
Measurement 179/177 ppm 1se 176/177(n) ppm 1se 178/177(n) ppm 1se mins Results obtained* for JMC475 Hafnium *Normalised to 179/177=.7325 Intensity for 1ppm 180Hf= 3Volts therefore total Hf 10volts/ppm 1 0.748263 17 0.282208 12 1.466992 4 40 2 0.747898 24 0.282187 18 1.467058 7 20 3 0.748067 23 0.282162 18 1.467074 8 20 4 0.747876 23 0.282155 19 1.467114 7 20 5 0.748184 14 0.282196 11 1.467061 8 20 6 0.748087 19 0.28221 15 1.467052 8 20 Mean 0.748062 0.282186 1.467058 1SD 0.000153 2.34x10-5 3.95x10-5 TIMS 0.7325 0.282195 >109 cps/ppm
Ion Yields Uranium 1.3 x109 cps/ppm Lead 4.2 x109 cps/ppm Hafnium 1.9 x109 cps/ppm Neodymium 2.5 x109 cps/ppm Strontium 2 x109 cps/ppm
99Tc at 1ppb Faradaybackground
Benefits of Multicollector ICP-MS • Extends the range of elements for which precise isotope ratios can be determined • e.g. Ca/Sr, Hf/Lu • Easy to add normalising spikes • Direct sampling with laser ablation • e.g. individual Zircons
Benefits of Single-focusing Multicollector ICP-HEX-MS • High transmission: Extreme sensitivity >109 cps/ppm • Faster analysis • Reliable analyses produced from smaller samples • Single shot laser ablation • Extends the range of elements even further • Ca, Fe, Se
Conclusion • Elimination of Ar based interferences • -Reduces detection limits on previously difficult elements such as K, Ca, Fe, As & Se • Reduces ion energy spread • -Increases resolution & sensitivity • -Enables precise isotope ratios to be measured on a single focussing multicollector ICP-MS