TY - JOUR
T1 - Analytical improvements and assessment of long-term performance of the oxidation–denitrifier method
AU - Moretti, Simone
AU - Duprey, Nicolas N.
AU - Foreman, Alan D.
AU - Arns, Anthea
AU - Brömme, Sven
AU - Jung, Jonathan
AU - Ai, Xuyuan E.
AU - Auderset, Alexandra
AU - Bieler, Aaron L.
AU - Eck, Camino
AU - Farmer, Jesse
AU - Hinnenberg, Barbara
AU - Lacerra, Matthew
AU - Leichliter, Jennifer
AU - Lüdecke, Tina
AU - Oleynik, Sergey
AU - Rubach, Florian
AU - Schmitt, Mareike
AU - Vink, Marissa
AU - Wald, Tanja
AU - Yehudai, Maayan
AU - Sigman, Daniel M.
AU - Martínez-García, Alfredo
N1 - Publisher Copyright:
© 2023 The Authors. Rapid Communications in Mass Spectrometry published by John Wiley & Sons Ltd.
PY - 2024/1/15
Y1 - 2024/1/15
N2 - The analysis of the nitrogen (N) isotopic composition of organic matter bound to fossil biomineral structures (BB-δ15N) using the oxidation–denitrifier (O–D) method provides a novel tool to study past changes in N cycling processes. Methods: We report a set of methodological improvements to the O–D method, including (a) a method for sealing the reaction vials in which the oxidation of organic N to NO3− takes place, (b) a recipe for bypassing the pH adjustment step before the bacterial conversion of NO3− to N2O, and (c) a method for storing recrystallized dipotassium peroxodisulfate (K2S2O8) under Ar atmosphere. Results: The new sealing method eliminates the occasional contamination and vial breakage that occurred previously while increasing sample throughput. The protocol for bypassing pH adjustment does not affect BB-δ15N, and it significantly reduces the processing time. Storage of K2S2O8 reagent under Ar atmosphere produces stable oxidation blanks over more than 3.5 years. We report analytical blanks, accuracy, and precision for this methodology from eight users over the course of ~3.5 years of analyses at the Max Planck Institute for Chemistry. Our method produces analytical blanks characterized by low N content (0.30 ± 0.13 nmol N, 1σ, n = 195) and stable δ15N (−2.20 ± 3.13‰, n = 195). The analysis of reference amino acid standards USGS 40 and USGS 65 indicates an overall accuracy of −0.23 ± 0.35‰ (1σ, n = 891). The analysis of in-house fossil standards gives similar analytical precision (1σ) across a range of BB-δ15N values and biominerals: zooxanthellate coral standard PO-1 (6.08 ± 0.21‰, n = 267), azooxanthellate coral standard LO-1 (10.20 ± 0.28‰, n = 258), foraminifera standard MF-1 (5.92 ± 0.28‰, n = 243), and tooth enamel AG-Lox (4.06 ± 0.49‰, n = 78). Conclusions: The methodological improvements significantly increase sample throughput without compromising analytical precision or accuracy down to 1 nmol of N.
AB - The analysis of the nitrogen (N) isotopic composition of organic matter bound to fossil biomineral structures (BB-δ15N) using the oxidation–denitrifier (O–D) method provides a novel tool to study past changes in N cycling processes. Methods: We report a set of methodological improvements to the O–D method, including (a) a method for sealing the reaction vials in which the oxidation of organic N to NO3− takes place, (b) a recipe for bypassing the pH adjustment step before the bacterial conversion of NO3− to N2O, and (c) a method for storing recrystallized dipotassium peroxodisulfate (K2S2O8) under Ar atmosphere. Results: The new sealing method eliminates the occasional contamination and vial breakage that occurred previously while increasing sample throughput. The protocol for bypassing pH adjustment does not affect BB-δ15N, and it significantly reduces the processing time. Storage of K2S2O8 reagent under Ar atmosphere produces stable oxidation blanks over more than 3.5 years. We report analytical blanks, accuracy, and precision for this methodology from eight users over the course of ~3.5 years of analyses at the Max Planck Institute for Chemistry. Our method produces analytical blanks characterized by low N content (0.30 ± 0.13 nmol N, 1σ, n = 195) and stable δ15N (−2.20 ± 3.13‰, n = 195). The analysis of reference amino acid standards USGS 40 and USGS 65 indicates an overall accuracy of −0.23 ± 0.35‰ (1σ, n = 891). The analysis of in-house fossil standards gives similar analytical precision (1σ) across a range of BB-δ15N values and biominerals: zooxanthellate coral standard PO-1 (6.08 ± 0.21‰, n = 267), azooxanthellate coral standard LO-1 (10.20 ± 0.28‰, n = 258), foraminifera standard MF-1 (5.92 ± 0.28‰, n = 243), and tooth enamel AG-Lox (4.06 ± 0.49‰, n = 78). Conclusions: The methodological improvements significantly increase sample throughput without compromising analytical precision or accuracy down to 1 nmol of N.
UR - http://www.scopus.com/inward/record.url?scp=85178929403&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85178929403&partnerID=8YFLogxK
U2 - 10.1002/rcm.9650
DO - 10.1002/rcm.9650
M3 - Article
C2 - 38073197
AN - SCOPUS:85178929403
SN - 0951-4198
VL - 38
JO - Rapid Communications in Mass Spectrometry
JF - Rapid Communications in Mass Spectrometry
IS - 1
M1 - e9650
ER -