Oxygen isotope analyses of biogenic opal and quartz using a novel microfluorination technique

Abstract

New data produced with the microfluorination technique are comparable with data from studies using existing methodologies. The microfluorination technique has the potential to greatly increase the number of laboratories producing silicate oxygen isotope data for mineralogic, paleoclimatic and biogeochemical applications.

An evaluation of paired δ18O and (234U/238U)0 in opal as a tool for paleoclimate reconstruction in semi-arid environments

“…However, this exchangeable water fraction can be removed with extensive pumping under vacuum (Knauth and Epstein, 1982). Biogenic silica deposits, such as diatom frustrules (Menicucci et al, 2013), which have large surface areas relative to our samples, may exchange 10 to 20 % of their oxygen upon coming in contact with atmospheric water or water vapor (Labeyrie and Juillet, 1982). Typically, adsorbed H 2 O and structural OHare removed prior to analysis by traditional mass spectrometric methods through heating under vacuum and/or stepwise or laser fluorination (e.g.…”

“…Typically, adsorbed H 2 O and structural OHare removed prior to analysis by traditional mass spectrometric methods through heating under vacuum and/or stepwise or laser fluorination (e.g. Dodd and Sharp, 2010;Menicucci et al, 2013). For SIMS analysis, an unknown amount of the more labile water is removed when the samples are repeatedly dried in a vacuum oven at 210 mbar and 55˚C, stored in a desiccator and then placed under moderate to high vacuum in the SEM and SIMS instruments (~7 x 10 -9 mbar for SHRIMP-RG analyses and ~3 × 10 -8 mbar for CAMECA IMS 1280 analyses).…”

Historical and contemporary stable isotope tracer approaches to studying mammalian protein metabolism

“…Stable isotope tracers are now at the forefront of the majority of physiological/biological mechanistic studies performed in vivo , and are complimented by the wealth of methodologies and techniques for determining flux through metabolic pathways and rates of substrate/pool turnover that are available, alongside the numerous analytical platforms which are now commercially available for the measurement of isotopic abundance. As a result, it is now possible to use stable isotope tracers for as diverse applications as medicine (Chan, Barrett, & Watts, ), diagnostics (Bonfrate et al, ), ecology (Garcia‐Anton et al, ), geology (Menicucci, Matthews, & Spero, ), forensics (Meier‐Augenstein et al, ), and art (Fortunato, Ritter, & Fabian, ), among many others. It is doubtful that even Schoenheimer himself could have envisaged where his experiments with deuterium in the 1930s would have led to today.…”

“…Over the subsequent decades, analytical, industrial, and chemistry breakthroughs have provided the capacity for stable isotope techniques/approaches to become unparalleled tools, not only in the chemical and physical sciences, but also in the geological, physiological, and medical sciences. As such, stable isotopes can now provide us with information on things as diverse as geology (Menicucci, Matthews, & Spero, ), archaeology (Negash et al, ), environmental impact on ecosystems (Zhou et al, ), the rates at which our body's build/breakdown tissues (Smith & Rennie, ), the effectiveness of a certain medical treatment or interventions (Schellekens et al, ), an individuals body composition (Kreisberg, Bowdoin, & Meador, ; Picou et al, ; Clark et al, ), the efficiency of our organs to function (Miele et al, ), and optimal nutrition for a healthy lifestyle (Rennie, ). Yet, this is only a snapshot of their potential uses, with future technical refinement and progress in MS development, there is no doubt that many more uses for these diverse tools will be in development.…”

“…Since their initial isolation and implementation in the 1930s, stable isotope tracers have provided the scientific community with great insight into the understanding of the metabolism underlying disease (Kao et al, ), aging (Cuthbertson et al, ), and genetic disorders (Mew, Yudkoff, & Tuchman, ). While predominantly used for studying biological systems, stable isotopes are not limited to this area, and today have a wide range of applications, such as, art, forensics, and geology (Fortunato, Ritter, & Fabian, ; Meier‐Augenstein et al, ; Menicucci, Matthews, & Spero, ). Stable isotopes are elements that occupy the same position in the periodic table, are essentially “ chemically and functionally identical ,” but differ in mass due to a different number of neutrons within the atomic nucleus.…”