Absolute isotopic abundance ratio and atomic weight of a reference sample of rhenium

Abstract

,An absolute value has been obtained for the isotopic abundance ratio of a reference sample of rhenium, using surface emission mass spectrometry. Samples of known isotopic composition , prepared from nearly isotopically pure se parat ed rhenium isotopes , were used to calibrate the mass spectrometers. The resulting absolute '85 Re/'·7 Re ratio is 0.59738 ± 0.00039, which yields atom per· cents of ' 8s Re=37 .398±0.016 and '87Re=62.602±0.016. The atomi c weight calculated from this isotopi c c omposition is 186.20679 ± 0.00031. The indi cated uncertainties are overall limits of e rror based on 95 perce nt confidence limits for th e mean and allowances for the effe cts of known sources of possible systematic error.

Simplified technique for the measurements of Re-Os isotope by multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS)

“…Initially, 187 Re/ 185 Re values were corrected for mass fractionation using an exponential law and assuming the same mass fractionation factor for Re and Ir. However, the corrected 187 Re/ 185 Re ratios showed a systematic deviation from reported values (Gramlich et al, 1973;Suzuki et al, 2004), in that the 187 Re/ 185 Re value obtained by MC-ICP-MS ( 187 Re/ 185 Re = 1.66969 ± 22) (Liang et al, 2005) was systematically lower (by approximately 0.35%) than the fractionationcorrected value determined by N-TIMS ( 187 Re/ 185 Re = 1.6755 ± 14) (Suzuki et al, 2004). It should also be noted that our values were significantly lower than the certified isotope ratio adopted by International Union of Pure and Applied Chemistry (IUPAC) ( 187 Re/ 185 Re = 1.6740 ± 11) (Rosman and Taylor, 1998).…”

“…To estimate the f value, we employed the Re isotopic data reported by Gramlich et al (1973), which is also adopted by IUPAC. The f value was optimized to minimize the deviations of all measured 187 Re/ 185 Re values of the Re standard from the reference value of 1.6740 (Gramlich et al, 1973;Rosman and Taylor, 1998). The overall average of the f value was 0.8512 ± 0.0016 (n = 20).…”

Rhenium in seawater: Confirmation of generally conservative behavior

“…The concentration of la5Re in both of these tracer solutions was determined by calibration against a gravimetrically prepared standard solution of isotopically normal, high purity Re metal (Johnson Matthey). The isotopic composition of the tracer solutions was determined by NTIMS in our laboratory ('s'Re/'*'Re = 37.14 + 0.04), and the isotopic composition of the standard solutions and natural samples is assumed to be 'ssRe/'87Re = 0.5974 + 0.0004 (GRAMLICH et al, 1973). The isotopic composition of Re standard solutions determined by NTIMS in our laboratory (0.5976 + 0.0003) is identical to the isotopic abundance ratio determined by GRAMLICH et al ( 1973), using carefully controlled procedures.…”

The Absolute Isotopic Abundance and Atomic Weight of a Reference Sample of Silver

“…Analysis under identical conditions of Hl9 Ag samples ranging in amount from 4 ILg to 0.005 .... g indicated a possible mass-I07 isobaric intenerence a.t a level of 1 (± 1) X [10][11][12][13][14][15][16] A. This level of interference is below the direct measurement detection Hmit of the instrument but can be inferred from the slight decrease in the observed 109/107 ratio with decreasing sample size.…”

“…The method used for the detennination of atomic weights at NBS, which has been briefly described in previous publications [1][2][3][4][5][6][7][8][9][10][11][12][13][14], and may be described as calibrated mass spectrometry, combines the techniques of high precision chemical assay with high precision mass spectrometry. The mass spectrometers to be used for the isotopic abundance measurements are calibrated for bias using synthetic mixes of known isotopic composition, prepared from nearly pure separated isotopes.…”