Abstract Details
(2020) Determination of the Isotopic Composition of an Enriched Hafnium Spike by MC-ICP-MS Using Regression Model
Lin R, Lin J, Zong K & Chen K
https://doi.org/10.46427/gold2020.1566
The author has not provided any additional details.
06n: Room 2, Wednesday 24th June 08:03 - 08:06
Ran Lin
Jie Lin View all 2 abstracts at Goldschmidt2020 View abstracts at 3 conferences in series
KeQing Zong View all 2 abstracts at Goldschmidt2020
Kang Chen View all 2 abstracts at Goldschmidt2020
Jie Lin View all 2 abstracts at Goldschmidt2020 View abstracts at 3 conferences in series
KeQing Zong View all 2 abstracts at Goldschmidt2020
Kang Chen View all 2 abstracts at Goldschmidt2020
Listed below are questions that have been submitted by the community that the author will try and cover in their presentation. To submit a question, ensure you are signed in to the website. Authors or session conveners approve questions before they are displayed here.
Submitted by Yuri Amelin on Wednesday 24th June 05:07
This presentation is interesting but also confusing. Here are three things that I don't understand: 1) What exactly do you mean by mass independent fractionation? This term is usually applied to the situation where a number of isotopes of an element (e.g. isotopes with even mass) follow a certain fractionation pattern, but some isotopes (e.g. odd mass isotopes) don't. These are the situations shown in your slide 7. What does it have to do with using another element for normalization? 2) Why standard - sample bracketing, such as shown in your slide 11, gives such a huge dispersion? This method is well suited for spike calibration, where concentration matching is easy, and matrix is absent. It also insensitive to MIF and does not require choosing fractionation law. The scattering you show is not normal. What causes it? 3) Why are you so keen to calibrate the spike by normalizing to another element rather than a synthetic gravimetric mixture of the isotopes of the same element?
Thanks for your questions. The following is my answer to the above questions. 1) The exponential mass-bias correction model (Russell’s law) has become a standard curriculum in isotope amount ratio measurements. In nature, however, isotopic fractionation that deviates significantly from the exponential model has been known for a long time. Recently, such fractionation was also observed in MC-ICP-MS.. This phenomenon is termed mass-independent fractionation (MIF). And we have not found that the MIF is related to the mass of isotopes. Moreover?the another element used as an internal standard reference material to calibrate the isotope ratio of interest element. 2) The SSB method is critically dependent on the matrix matching, the signal of 180Hf in Hf spike is too high and the 176Hf and 179Hf were too low to matrix matching with the standard. (e.g. the 180Hf of spike Hf ~46V, the 180 of Alfa Hf standard solution~5V, the 176Hf of Hf spike ~0.04V ). In addition, the regression method relies on the availability of a primary isotope reference material of another element. The regression method relies on the availability of a primary isotope reference material of another element. In addition, the regression model is capable of correcting sample matrix-induced bias occurring in MC-ICP-MS, since the analyte and calibrant isotope ratios are measured from the same solution. As a result, matrix separation is not required as long as no significant spectroscopy interference exists on the isotopes of interest. 3) Since the (Full) gravimetric isotope mixture model is based on sequential measurements of enriched materials and their mixtures, matrix matching in both analyte and matrix element concentrations is required. In addition, a longer instrument warm-up time is needed to ensure its stability and a short measurement time is critical to minimize the temporal drift in isotopic fractionation. One of the major advantages of this FGIM isotopic fractionation correction model is its applicability to small sample size.
This presentation is interesting but also confusing. Here are three things that I don't understand: 1) What exactly do you mean by mass independent fractionation? This term is usually applied to the situation where a number of isotopes of an element (e.g. isotopes with even mass) follow a certain fractionation pattern, but some isotopes (e.g. odd mass isotopes) don't. These are the situations shown in your slide 7. What does it have to do with using another element for normalization? 2) Why standard - sample bracketing, such as shown in your slide 11, gives such a huge dispersion? This method is well suited for spike calibration, where concentration matching is easy, and matrix is absent. It also insensitive to MIF and does not require choosing fractionation law. The scattering you show is not normal. What causes it? 3) Why are you so keen to calibrate the spike by normalizing to another element rather than a synthetic gravimetric mixture of the isotopes of the same element?
Thanks for your questions. The following is my answer to the above questions. 1) The exponential mass-bias correction model (Russell’s law) has become a standard curriculum in isotope amount ratio measurements. In nature, however, isotopic fractionation that deviates significantly from the exponential model has been known for a long time. Recently, such fractionation was also observed in MC-ICP-MS.. This phenomenon is termed mass-independent fractionation (MIF). And we have not found that the MIF is related to the mass of isotopes. Moreover?the another element used as an internal standard reference material to calibrate the isotope ratio of interest element. 2) The SSB method is critically dependent on the matrix matching, the signal of 180Hf in Hf spike is too high and the 176Hf and 179Hf were too low to matrix matching with the standard. (e.g. the 180Hf of spike Hf ~46V, the 180 of Alfa Hf standard solution~5V, the 176Hf of Hf spike ~0.04V ). In addition, the regression method relies on the availability of a primary isotope reference material of another element. The regression method relies on the availability of a primary isotope reference material of another element. In addition, the regression model is capable of correcting sample matrix-induced bias occurring in MC-ICP-MS, since the analyte and calibrant isotope ratios are measured from the same solution. As a result, matrix separation is not required as long as no significant spectroscopy interference exists on the isotopes of interest. 3) Since the (Full) gravimetric isotope mixture model is based on sequential measurements of enriched materials and their mixtures, matrix matching in both analyte and matrix element concentrations is required. In addition, a longer instrument warm-up time is needed to ensure its stability and a short measurement time is critical to minimize the temporal drift in isotopic fractionation. One of the major advantages of this FGIM isotopic fractionation correction model is its applicability to small sample size.
Sign in to ask a question.