Abstract
The precision and accuracy of lead isotope-ratio determination on a short transient signal has been assessed by coupling capillary gas chromatography to the Isoprobe (Micromass, UK), a single-focusing inductively coupled plasma mass spectrometer with multicollector detection. A T-piece connecting the GC transfer line to the torch enabled continuous aspiration of thallium solution for mass-bias correction. The volatile lead species PbEt4 was derivatized from NIST isotopic certified lead standard SRM 981 and different amounts of PbEt4 dissolved in iso-octane were injected into the GC. Chromatograms were recorded in multicollection mode by use of Faraday cups; seven isotopes (Pb-204, Pb-206, Pb-207, Pb-208, Tl-203, Tl-205, and Hg-202) were monitored simultaneously at a transient resolution of 160 ms. PbEt4 peaks were obtained with a half-width of 1.2 s and a base width of 3.5 s. Lead isotope ratios were calculated from the peak areas integrated for each lead isotope, giving precision in the range of 0.02 to 0.07% for ratios of high-abundant isotopes and injections of 5 and 50 pg absolute amount as lead (five replicates). Mass bias was found to be about 0.5% per mass unit and was corrected by using the continuously measured thallium signals at Tl-203 and Tl-205. After mass-bias correction, deviation of the certified lead ratio values was found to be in the range of 0.02 to 0.15% accuracy.
Original language | English |
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Pages (from-to) | 573-580 |
Number of pages | 8 |
Journal | Fresenius’ Journal of Analytical Chemistry |
Volume | 370 |
Issue number | 5 |
Publication status | Published - Jul 2001 |
Keywords
- PLASMA-MASS SPECTROMETRY
- SPECIATION ANALYSIS
- TRACE-METAL
- FRACTIONATION
- SEDIMENTS
- DILUTION
- PB
- REDUCTION
- SAMPLES
- WINE