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Fu Y, Zhang R, Rong S, Wu Y, Wu Y, Ya M. A methodological review of compound-specific radiocarbon analysis for polycyclic aromatic hydrocarbons in environmental matrices. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 350:124050. [PMID: 38677454 DOI: 10.1016/j.envpol.2024.124050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 04/23/2024] [Accepted: 04/24/2024] [Indexed: 04/29/2024]
Abstract
Identifying the sources of polycyclic aromatic hydrocarbons (PAHs) in complex environmental matrices is essential for understanding the impact of combustion-related human activities on the environment. Since the turn of the century, advances in analytical capability and accuracy of accelerator mass spectrometry (AMS) have made it possible to accurately determine the source apportionment of PAHs based on their radiocarbon (14C) mass conservation. This also allows us to trace the environmental transport processes of PAHs from the perspective of molecular 14C. However, natural environmental matrices have very low concentrations of PAHs (ppb to ppm level). To meet the requirements of carbon weight for 14C measurement by AMS, trace PAHs in complex environmental matrices must be enriched thousands of times, and then higher purity individual PAH molecules should be obtained through a series of complex purification procedures. Therefore, the technical difficulty is the main challenge in expanding the application of compound-specific 14C analysis in environmental science. This article reviews the detailed pretreatment procedures for 14C measurement of specific PAHs, including sample enrichment, extraction and purification of aromatic components, preparation of compound-specific PAHs by preparative capillary gas chromatography, graphitization of samples with ultra-small carbon content, and relevant quality control and assurance procedures. This study aims to help environmental geoscientists understand the technical process of 14C analysis of PAHs and inspire new scientific questions related to environmental science. To our knowledge, this is the first comprehensive review of the technical method of compound-specific 14C analysis for PAHs.
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Affiliation(s)
- Yu Fu
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, China; State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, China
| | - Rui Zhang
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, China; State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, China
| | - Shaopeng Rong
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, China
| | - Yuling Wu
- School of Marine Sciences, Nanjing University of Information Science & Technology, Nanjing 210044, China
| | - Ying Wu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, China
| | - Miaolei Ya
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, China.
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Wabnitz C, Chen W, Elsner M, Bakkour R. Quartz Crystal Microbalance as a Holistic Detector for Quantifying Complex Organic Matrices during Liquid Chromatography: 2. Compound-Specific Isotope Analysis. Anal Chem 2024; 96:7436-7443. [PMID: 38700939 PMCID: PMC11099894 DOI: 10.1021/acs.analchem.3c05441] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 03/22/2024] [Accepted: 04/17/2024] [Indexed: 05/05/2024]
Abstract
In carbon-compound-specific isotope analysis (carbon CSIA) of environmental micropollutants, purification of samples is often required to guarantee accurate measurements of a target compound. A companion paper has brought forward an innovative approach to couple a quartz crystal microbalance (QCM) with high-performance liquid chromatography (HPLC) for the online quantification of matrices during a gradient HPLC purification. This work investigates the benefit for isotope analysis of polar micropollutants typically present in environmental samples. Here, we studied the impact of the natural organic matter (NOM) on the isotopic integrity of model analytes and the suitability of the NOM-to-analyte ratio as a proxy for the sample purity. We further investigated limitations and enhancement of HPLC purification using QCM on C18 and C8 phases for single and multiple targets. Strong isotopic shifts of up to 3.3% toward the isotopic signature of NOM were observed for samples with an NOM-to-analyte ratio ≥10. Thanks to QCM, optimization of matrix removal of up to 99.8% of NOM was possible for late-eluting compounds. The efficiency of HPLC purification deteriorated when aiming for simultaneous purification of two or three compounds, leading to up to 2.5% less NOM removal. Our results suggest that one optimized HPLC purification can be achieved through systematic screening of 3 to 5 different gradients, thereby leading to a shift of the boundaries of accurate carbon CSIA by up to 2 orders of magnitude toward lower micropollutant concentrations.
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Affiliation(s)
- Christopher Wabnitz
- Department of Chemistry, Chair of Analytical
Chemistry and Water Chemistry, TUM School of Natural Sciences, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Wei Chen
- Department of Chemistry, Chair of Analytical
Chemistry and Water Chemistry, TUM School of Natural Sciences, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Martin Elsner
- Department of Chemistry, Chair of Analytical
Chemistry and Water Chemistry, TUM School of Natural Sciences, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Rani Bakkour
- Department of Chemistry, Chair of Analytical
Chemistry and Water Chemistry, TUM School of Natural Sciences, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany
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Sun Y, Ogawa NO, Ishikawa NF, Blattmann TM, Takano Y, Ohkouchi N. Application of a porous graphitic carbon column to carbon and nitrogen isotope analysis of underivatized individual amino acids using high-performance liquid chromatography coupled with elemental analyzer/isotope ratio mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2023; 37:e9602. [PMID: 37580505 DOI: 10.1002/rcm.9602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/30/2023] [Accepted: 07/03/2023] [Indexed: 08/16/2023]
Abstract
RATIONALE Isolation of underivatized amino acids (AAs) using high-performance liquid chromatography (HPLC) is becoming a popular method for carbon (δ13 C) and nitrogen isotope (δ15 N) analyses of AAs because of the high analytical precision and for performing dual-isotope analysis. However, some AAs in natural samples, especially small, hydrophilic AAs, are not suitably separated using reversed-phase columns (e.g., C18) and ion-exchange columns (e.g., Primesep A). METHODS We developed a new method for HPLC using a porous graphitic carbon column for the separation of nine hydrophilic AAs. After purification, δ13 C and δ15 N values of AAs were determined using elemental analyzer/isotope ratio mass spectrometry (EA/IRMS). We demonstrated the application of this method by determining δ13 C and δ15 N values of individual hydrophilic AAs in a biological sample, the muscle of blue mackerel (Scomber australasicus). RESULTS Chromatographically, the baseline separation of hydrophilic AAs was achieved in both the standard mixture and the biological sample. We confirmed that δ13 C and δ15 N values of AA standards remained unchanged during the whole experimental procedure. The δ13 C values of AAs in mackerel muscle are also in good agreement with the values obtained using another verified method for δ13 C analysis. CONCLUSIONS The good separation performance of hydrophilic AAs and the reliability of δ13 C and δ15 N analyses of individual AAs using the porous graphite column offer a significant advantage over conventional settings. We suggest that, in the future, the HPLC × EA/IRMS method can be used for reliable δ13 C and δ15 N analyses of AAs in natural samples.
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Affiliation(s)
- Yuchen Sun
- Biogeochemistry Research Center (BGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan
- Atmosphere and Ocean Research Institute (AORI), The University of Tokyo, Kashiwa, Japan
- Department of Earth and Planetary Science, The University of Tokyo, Tokyo, Japan
| | - Nanako O Ogawa
- Biogeochemistry Research Center (BGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan
| | - Naoto F Ishikawa
- Biogeochemistry Research Center (BGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan
| | - Thomas M Blattmann
- Biogeochemistry Research Center (BGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan
- Geological Institute, ETH Zürich, Zürich, Switzerland
| | - Yoshinori Takano
- Biogeochemistry Research Center (BGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan
| | - Naohiko Ohkouchi
- Biogeochemistry Research Center (BGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan
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4
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Sun Y, Ishikawa NF, Ogawa NO, Kawahata H, Takano Y, Ohkouchi N. A method for stable carbon isotope measurement of underivatized individual amino acids by multi-dimensional high-performance liquid chromatography and elemental analyzer/isotope ratio mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2020; 34:e8885. [PMID: 32656862 DOI: 10.1002/rcm.8885] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 07/08/2020] [Accepted: 07/10/2020] [Indexed: 06/11/2023]
Abstract
RATIONALE To achieve better precision and accuracy for δ13 C analysis of individual amino acids (AAs), we have developed a new analytical method based on multi-dimensional high-performance liquid chromatography (HPLC) and elemental analyzer/isotope ratio mass spectrometry (EA/IRMS). Unlike conventional methods using gas chromatography, this approach omits pre-column chemical derivatization, thus reducing systematic errors associated with the isotopic measurement. METHODS The separation and isolation of individual AAs in a standard mixture containing 15 AAs and a biological sample, spear squid (Heterololigo bleekeri) were performed. AAs were isolated using an HPLC system equipped with a reversed-phase column and a mixed-mode column and collected using a fraction collector. After the chromatographic separation and further post-HPLC purification, the δ13 C values of AAs were measured by EA/IRMS. RESULTS The complete isolation of all 15 AAs in the standard mixture was achieved. The δ13 C values of these AAs before and after the experiment were in good agreement. Also, 15 AAs in the biological sample, H. bleekeri, were successfully measured. The δ13 C values of AAs in H. bleekeri varied by as much as 30‰ with glycine being most enriched in13 C. CONCLUSIONS The consistency between the δ13 C values of reference and processed AAs demonstrates that the experimental procedure generates accurate δ13 C values unaffected by fractionation effects and contamination. This method is therefore suitable for δ13 C analysis of biological samples with higher precision than conventional approaches. We propose this new method as a tool to measure δ13 C values of AAs in biological, ecological and biogeochemical studies.
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Affiliation(s)
- Yuchen Sun
- Biogeochemistry Research Center (BGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan
- Atmosphere and Ocean Research Institute (AORI), The University of Tokyo, Kashiwa, Japan
- Department of Earth and Planetary Science, The University of Tokyo, Tokyo, Japan
| | - Naoto F Ishikawa
- Biogeochemistry Research Center (BGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan
| | - Nanako O Ogawa
- Biogeochemistry Research Center (BGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan
| | - Hodaka Kawahata
- Atmosphere and Ocean Research Institute (AORI), The University of Tokyo, Kashiwa, Japan
- Department of Earth and Planetary Science, The University of Tokyo, Tokyo, Japan
| | - Yoshinori Takano
- Biogeochemistry Research Center (BGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan
- Department of Earth and Planetary Science, The University of Tokyo, Tokyo, Japan
| | - Naohiko Ohkouchi
- Biogeochemistry Research Center (BGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan
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Abstract
Single-compound analysis of stable or radioactive isotopes has found application in a number of fields ranging from archaeology to forensics. Often, the most difficult part of these analyses is the development of a method for isolating the compound(s) of interest, which can derive from a wide range of sample types including the hair, nails, and bone.Here we describe three complementary preparative HPLC techniques suitable for separating and isolating amino acids from bone collagen and hair keratin. Using preparative reversed-phase, ion-pair, or mixed-mode chromatography in aqueous carbon-free mobile phases, or those from which carbon can easily be removed, underivatized single amino acids can be isolated and further analyzed using mass spectrometric techniques.
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Ishikawa NF, Itahashi Y, Blattmann TM, Takano Y, Ogawa NO, Yamane M, Yokoyama Y, Nagata T, Yoneda M, Haghipour N, Eglinton TI, Ohkouchi N. Improved Method for Isolation and Purification of Underivatized Amino Acids for Radiocarbon Analysis. Anal Chem 2018; 90:12035-12041. [DOI: 10.1021/acs.analchem.8b02693] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Naoto F. Ishikawa
- Department of Earth Sciences, ETH Zürich, 8092 Zürich, Switzerland
- Department of Biogeochemistry, Japan Agency for Marine-Earth Science and Technology, Yokosuka 237-0061, Japan
| | - Yu Itahashi
- Department of Biogeochemistry, Japan Agency for Marine-Earth Science and Technology, Yokosuka 237-0061, Japan
- The University Museum, The University of Tokyo, Tokyo 113-0033, Japan
| | | | - Yoshinori Takano
- Department of Biogeochemistry, Japan Agency for Marine-Earth Science and Technology, Yokosuka 237-0061, Japan
| | - Nanako O. Ogawa
- Department of Biogeochemistry, Japan Agency for Marine-Earth Science and Technology, Yokosuka 237-0061, Japan
| | - Masako Yamane
- Department of Biogeochemistry, Japan Agency for Marine-Earth Science and Technology, Yokosuka 237-0061, Japan
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa 277-8562, Japan
- Institute for Space-Earth Environmental Research, Nagoya University, Nagoya 464-8601, Japan
| | - Yusuke Yokoyama
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa 277-8562, Japan
| | - Toshi Nagata
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa 277-8562, Japan
| | - Minoru Yoneda
- The University Museum, The University of Tokyo, Tokyo 113-0033, Japan
| | - Negar Haghipour
- Department of Earth Sciences, ETH Zürich, 8092 Zürich, Switzerland
- Laboratory for Ion Beam Physics, ETH Zürich, 8093 Zürich, Switzerland
| | | | - Naohiko Ohkouchi
- Department of Biogeochemistry, Japan Agency for Marine-Earth Science and Technology, Yokosuka 237-0061, Japan
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Bravenec AD, Ward KD, Ward TJ. Amino acid racemization and its relation to geochronology and archaeometry. J Sep Sci 2018; 41:1489-1506. [DOI: 10.1002/jssc.201701506] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 02/15/2018] [Accepted: 02/15/2018] [Indexed: 11/11/2022]
Affiliation(s)
- Ardith D. Bravenec
- School of GeoSciences; Grant Institute; University of Edinburgh; Edinburgh UK
| | - Karen D. Ward
- Department of Chemistry and Biochemistry; Keck Center for Instrumental and Biochemical Comparative Archaeology; Millsaps College; Jackson MS USA
| | - Timothy J. Ward
- Department of Chemistry and Biochemistry; Keck Center for Instrumental and Biochemical Comparative Archaeology; Millsaps College; Jackson MS USA
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Zhang S, Zhong Q, Wang D, Huang Z, Li G. Measurement of the 15N/ 14N ratio of phenylalanine in fermentation matrix by isotope ratio mass spectrometry. Biotechnol Lett 2017; 39:1853-1857. [PMID: 28983702 DOI: 10.1007/s10529-017-2387-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 06/21/2017] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To determine the origin of 15N-labeled phenylalanine in microbial metabolic flux analysis using 15N as a tracer, a method for measuring phenylalanine δ15N using HPLC coupled with elemental analysis-isotope ratio mass spectrometry (EA-IRMS) was developed. RESULTS The original source of the 15N-labeled phenylalanine was determined using this new method that consists of three steps: optimization of the HPLC conditions, evaluation of the isotope fractionation effects, and evaluation of the effect of pre-processing on the phenylalanine nitrogen stable isotope. In addition, the use of a 15N-labeled inorganic nitrogen source, rather than 15N-labeled amino acids, was explored using this method. CONCLUSIONS The method described here can also be applied to the analysis of metabolic flux.
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Affiliation(s)
- Shiwei Zhang
- School of Chemical & Environmental Engineering, China University of Mining and Technology (Beijing), Beijing, 100083, China
- China National Institute of Food and Fermentation Industries, Beijing, 100015, China
- National Standardization Center of Food & Fermentation Industry, Beijing, 100015, China
| | - Qiding Zhong
- China National Institute of Food and Fermentation Industries, Beijing, 100015, China.
- National Standardization Center of Food & Fermentation Industry, Beijing, 100015, China.
| | - Daobing Wang
- China National Institute of Food and Fermentation Industries, Beijing, 100015, China
- National Standardization Center of Food & Fermentation Industry, Beijing, 100015, China
| | - Zhanbin Huang
- School of Chemical & Environmental Engineering, China University of Mining and Technology (Beijing), Beijing, 100083, China
| | - Guohui Li
- China National Institute of Food and Fermentation Industries, Beijing, 100015, China
- National Standardization Center of Food & Fermentation Industry, Beijing, 100015, China
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Broek TAB, Walker BD, Andreasen DH, McCarthy MD. High-precision measurement of phenylalanine δ15N values for environmental samples: a new approach coupling high-pressure liquid chromatography purification and elemental analyzer isotope ratio mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2013; 27:2327-2337. [PMID: 24097388 DOI: 10.1002/rcm.6695] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 07/19/2013] [Accepted: 07/20/2013] [Indexed: 06/02/2023]
Abstract
RATIONALE Compound-specific isotope analysis of individual amino acids (CSI-AA) is a powerful new tool for tracing nitrogen (N) source and transformation in biogeochemical cycles. Specifically, the δ(15)N value of phenylalanine (δ(15)N(Phe)) represents an increasingly used proxy for source δ(15)N signatures, with particular promise for paleoceanographic applications. However, current derivatization/gas chromatography methods require expensive and relatively uncommon instrumentation, and have relatively low precision, making many potential applications impractical. METHODS A new offline approach has been developed for high-precision δ(15)N measurements of amino acids (δ(15)N(AA)), optimized for δ(15)N(Phe) values. Amino acids (AAs) are first purified via high-pressure liquid chromatography (HPLC), using a mixed-phase column and automated fraction collection. The δ(15)N values are determined via offline elemental analyzer-isotope ratio mass spectrometry (EA-IRMS). RESULTS The combined HPLC/EA-IRMS method separated most protein AAs with sufficient resolution to obtain accurate δ(15)N values, despite significant intra-peak isotopic fractionation. For δ(15)N(Phe) values, the precision was ±0.16‰ for standards, 4× better than gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS; ±0.64‰). We also compared a δ(15)N(Phe) paleo-record from a deep-sea bamboo coral from Monterey Bay, CA, USA, using our method versus GC/C/IRMS. The two methods produced equivalent δ(15)N(Phe) values within error; however, the δ(15)N(Phe) values from HPLC/EA-IRMS had approximately twice the precision of GC/C/IRMS (average stdev of 0.27‰ ± 0.14‰ vs 0.60‰ ± 0.20‰, respectively). CONCLUSIONS These results demonstrate that offline HPLC represents a viable alternative to traditional GC/C/IMRS for δ(15)N(AA) measurement. HPLC/EA-IRMS is more precise and widely available, and therefore useful in applications requiring increased precision for data interpretation (e.g. δ(15)N paleoproxies).
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Affiliation(s)
- Taylor A B Broek
- Ocean Sciences Department, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA, 95064, USA
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10
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Boudin M, Boeckx P, Vandenabeele P, Van Strydonck M. Improved radiocarbon dating for contaminated archaeological bone collagen, silk, wool and hair samples via cross-flow nanofiltrated amino acids. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2013; 27:2039-2050. [PMID: 23943325 DOI: 10.1002/rcm.6652] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 05/08/2013] [Accepted: 06/05/2013] [Indexed: 06/02/2023]
Abstract
RATIONALE Radiocarbon dating and stable isotope analyses of bone collagen, wool, hair and silk contaminated with extraneous carbon (e.g. humic substances) does not yield reliable results if these materials are pre-treated using conventional methods. METHODS A cross-flow nanofiltration method was developed that can be applied to various protein materials like collagen, hair, silk, wool and leather, and should be able to remove low-molecular and high-molecular weight contaminants. To avoid extraneous carbon contamination via the filter a ceramic filter (molecular weight cut-off of 200 Da) was used. The amino acids, released by hot acid hydrolysis of the protein material, were collected in the permeate and contaminants in the retentate (>200 Da). RESULTS (14)C-dating results for various contaminated archaeological samples were compared for bulk material (pre-treated with the conventional methods) and for cross-flow nanofiltrated amino acids (permeate) originating from the same samples. Contamination and quality control of (14)C dates of bulk and permeate samples were obtained by measuring C:N ratios, fluorescence spectra, and δ(13)C and δ(15)N values of the samples. Cross-flow nanofiltration decreases the C:N ratio which means that contaminants have been removed. CONCLUSIONS Cross-flow nanofiltration clearly improved sample quality and (14)C results. It is a quick and non-labor-intensive technique and can easily be implemented in any (14)C and stable isotope laboratory for routine sample pre-treatment analyses.
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Affiliation(s)
- Mathieu Boudin
- Royal Institute for Cultural Heritage, Jubelpark 1, B-1000, Brussels, Belgium.
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11
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Sarachine Falso MJ, Buchholz BA. Bomb Pulse Biology. NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH. SECTION B, BEAM INTERACTIONS WITH MATERIALS AND ATOMS 2013; 294:666-670. [PMID: 23359559 PMCID: PMC3555406 DOI: 10.1016/j.nimb.2012.08.045] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The past decade has seen an explosion in use of the (14)C bomb-pulse to do fundamental cell biology. Studies in the 1960's used decay counting to measure tissue turnover when the atmospheric (14)C/C concentration was changing rapidly. Today bulk tissue measurements are of marginal interest since most of the carbon in the tissue resides in proteins, lipids and carbohydrates that turn over rapidly. Specific cell types with specialized functions are the focus of cell turnover investigations. Tissue samples need to be fresh or frozen. Fixed or preserved samples contain petroleum-derived carbon that has not been successfully removed. Cell or nuclear surface markers are used to sort specific cell types, typically by fluorescence-activated cell sorting (FACS). Specific biomolecules need to be isolated with high purity and accelerator mass spectrometry (AMS) measurements must accommodate samples that generally contain less than 40 micrograms of carbon. Furthermore, all separations must not add carbon to the sample. Independent means such as UV absorbance must be used to confirm molecule purity. Approaches for separating specific proteins and DNA and combating contamination of undesired molecules are described.
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12
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Single amino acid radiocarbon dating of Upper Paleolithic modern humans. Proc Natl Acad Sci U S A 2012; 109:6878-81. [PMID: 22517758 DOI: 10.1073/pnas.1116328109] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Archaeological bones are usually dated by radiocarbon measurement of extracted collagen. However, low collagen content, contamination from the burial environment, or museum conservation work, such as addition of glues, preservatives, and fumigants to "protect" archaeological materials, have previously led to inaccurate dates. These inaccuracies in turn frustrate the development of archaeological chronologies and, in the Paleolithic, blur the dating of such key events as the dispersal of anatomically modern humans. Here we describe a method to date hydroxyproline found in collagen (~10% of collagen carbon) as a bone-specific biomarker that removes impurities, thereby improving dating accuracy and confidence. This method is applied to two important sites in Russia and allows us to report the earliest direct ages for the presence of anatomically modern humans on the Russian Plain. These dates contribute considerably to our understanding of the emergence of the Mid-Upper Paleolithic and the complex suite of burial behaviors that begin to appear during this period.
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Tripp JA, McCullagh JSO. Preparative HPLC separation of underivatized amino acids for isotopic analysis. Methods Mol Biol 2012; 828:339-350. [PMID: 22125157 DOI: 10.1007/978-1-61779-445-2_27] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Single-compound analysis of stable or radio-isotopes has found application in a number of fields ranging from archaeology to forensics. Often, the most difficult part of these analyses is the development of a method for isolating the compounds of interest.Here, we describe three complementary preparative HPLC procedures suitable for separating and isolating single amino acids from bone collagen or hair keratin with minimal isotopic contamination. Using preparative reversed-phase, ion-pair, or mixed-mode chromatography of underivatized amino acids in aqueous mobile phases, single amino acids can be isolated and further analyzed using mass spectrometric techniques.
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Affiliation(s)
- Jennifer A Tripp
- Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, CA, USA.
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14
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Lynch AH, McCullagh JSO, Hedges REM. Liquid chromatography/isotope ratio mass spectrometry measurement of δ13C of amino acids in plant proteins. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2011; 25:2981-2988. [PMID: 21953952 DOI: 10.1002/rcm.5142] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In archaeological studies, the isotopic enrichment values of carbon and nitrogen in bone collagen give a degree of information on dietary composition. The isotopic enrichments of individual amino acids from bone collagen and dietary protein have the potential to provide more precise information about the components of diet. A limited amount of work has been done on this, although the reliability of these studies is potentially limited by fractionation arising through hydrolysis of whole plant tissue (where reaction between amino acids and carbohydrates may occur) and, for certain amino acids, the use of derivatives (particularly trifluoroacetyl derivatives) for gas chromatography/isotope ratio mass spectrometry (GC/IRMS) analysis. The present study takes the approach of extracting the protein components of plant tissues before hydrolysis and using liquid chromatography/isotope ratio mass spectrometry (LC/IRMS), which does not require derivatisation, for measurement of the isotopic enrichment of the amino acids. The protocol developed offers a methodology for consistent measurement of the δ(13)C values of amino acids, allowing isotopic differences between the individual amino acids from different plant tissues to be identified. In particular, there are highly significant differences between leaf and seed protein amino acids (leaf minus grain) in the cases of threonine (-4.1‰), aspartic acid (+3.5‰) and serine (-3.2‰). In addition to its intended application in archaeology, the technique will be of value in the fields of plant sciences, nutrition and environmental food-web studies.
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Affiliation(s)
- Anthony H Lynch
- Laboratory for Archaeology and the History of Art, University of Oxford, Oxford, UK
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15
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Abaye DA, Morrison DJ, Preston T. Strong anion exchange liquid chromatographic separation of protein amino acids for natural 13C-abundance determination by isotope ratio mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2011; 25:429-435. [PMID: 21213362 DOI: 10.1002/rcm.4844] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Amino acids are the building blocks of proteins and the analysis of their (13)C abundances is greatly simplified by the use of liquid chromatography (LC) systems coupled with isotope ratio mass spectrometry (IRMS) compared with gas chromatography (GC)-based methods. To date, various cation exchange chromatography columns have been employed for amino acid separation. Here, we report strong anion exchange chromatography (SAX) coupled to IRMS with a Liquiface interface for amino acid δ(13)C determination. Mixtures of underivatised amino acids (0.1-0.5 mM) and hydrolysates of representative proteins (prawns and bovine serum albumin) were resolved by LC/IRMS using a SAX column and inorganic eluents. Background inorganic carbon content was minimised through careful preparation of alkaline reagents and use of a pre-injector on-line carbonate removal device. SAX chromatography completely resolved 11 of the 16 expected protein amino acids following acid hydrolysis in underivatised form. Basic and neutral amino acids were resolved with 35 mM NaOH in isocratic mode. Elution of the aromatic and acidic amino acids required a higher hydroxide concentration (180 mM) and a counterion (NO 3-, 5-25 mM). The total run time was 70 min. The average δ(13)C precision of baseline-resolved peaks was 0.75‰ (range 0.04 to 1.06‰). SAX is a viable alternative to cation chromatography, especially where analysis of basic amino acids is important. The technology shows promise for (13)C amino acid analysis in ecology, archaeology, forensic science, nutrition and protein metabolism.
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Affiliation(s)
- Daniel A Abaye
- Stable Isotope Biochemistry Laboratory, Scottish Universities Environmental Research Centre, Rankine Avenue, Scottish Enterprise Technology Park, East Kilbride, Glasgow G75 0QF, UK
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Lynnerup N, Kjeldsen H, Zweihoff R, Heegaard S, Jacobsen C, Heinemeier J. Ascertaining year of birth/age at death in forensic cases: A review of conventional methods and methods allowing for absolute chronology. Forensic Sci Int 2010; 201:74-8. [DOI: 10.1016/j.forsciint.2010.03.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Revised: 03/17/2010] [Accepted: 03/19/2010] [Indexed: 10/19/2022]
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McCullagh JSO. Mixed-mode chromatography/isotope ratio mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2010; 24:483-494. [PMID: 20162548 DOI: 10.1002/rcm.4322] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Liquid chromatography coupled to molecular mass spectrometry (LC/MS) has been a standard technique since the early 1970s but liquid chromatography coupled to high-precision isotope ratio mass spectrometry (LC/IRMS) has only been available commercially since 2004. This development has, for the first time, enabled natural abundance and low enrichment delta(13)C measurements to be applied to individual analytes in aqueous mixtures creating new opportunities for IRMS applications, particularly for the isotopic study of biological molecules. A growing number of applications have been published in a range of areas including amino acid metabolism, carbohydrates studies, quantification of cellular and plasma metabolites, dietary tracer and nucleic acid studies. There is strong potential to extend these to new compounds and complex matrices but several challenges face the development of LC/IRMS methods. To achieve accurate isotopic measurements, HPLC separations must provide baseline-resolution between analyte peaks; however, the design of current liquid interfaces places severe restrictions on compatible flow rates and in particular mobile phase compositions. These create a significant challenge on which reports associated with LC/IRMS have not previously focused. Accordingly, this paper will address aspects of chromatography in the context of LC/IRMS, in particular focusing on mixed-mode separations and their benefits in light of these restrictions. It aims to provide an overview of mixed-mode stationary phases and of ways to improve high aqueous separations through manipulation of parameters such as column length, temperature and mobile phase pH. The results of several practical experiments are given using proteogenic amino acids and nucleosides both of which are of noted importance in the LC/IRMS literature. This communication aims to demonstrate that mixed-mode stationary phases provide a flexible approach given the constraints of LC/IRMS interface design and acts as a practical guide for the development of new chromatographic methods compatible with LC/IRMS applications.
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Affiliation(s)
- James S O McCullagh
- Chemistry Research Laboratory, University of Oxford, Mansfield Rd, Oxford OX1 3TA, UK.
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Godin JP, Fay LB, Hopfgartner G. Liquid chromatography combined with mass spectrometry for 13C isotopic analysis in life science research. MASS SPECTROMETRY REVIEWS 2007; 26:751-74. [PMID: 17853432 DOI: 10.1002/mas.20149] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Among the different disciplines covered by mass spectrometry, measurement of (13)C/(12)C isotopic ratio crosses a large section of disciplines from a tool revealing the origin of compounds to more recent approaches such as metabolomics and proteomics. Isotope ratio mass spectrometry (IRMS) and molecular mass spectrometry (MS) are the two most mature techniques for (13)C isotopic analysis of compounds, respectively, for high and low-isotopic precision. For the sample introduction, the coupling of gas chromatography (GC) to either IRMS or MS is state of the art technique for targeted isotopic analysis of volatile analytes. However, liquid chromatography (LC) also needs to be considered as a tool for the sample introduction into IRMS or MS for (13)C isotopic analyses of non-volatile analytes at natural abundance as well as for (13)C-labeled compounds. This review presents the past and the current processes used to perform (13)C isotopic analysis in combination with LC. It gives particular attention to the combination of LC with IRMS which started in the 1990's with the moving wire transport, then subsequently moved to the chemical reaction interface (CRI) and was made commercially available in 2004 with the wet chemical oxidation interface (LC-IRMS). The LC-IRMS method development is also discussed in this review, including the possible approaches for increasing selectivity and efficiency, for example, using a 100% aqueous mobile phase for the LC separation. In addition, applications for measuring (13)C isotopic enrichments using atmospheric pressure LC-MS instruments with a quadrupole, a time-of-flight, and an ion trap analyzer are also discussed as well as a LC-ICPMS using a prototype instrument with two quadrupoles.
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Affiliation(s)
- Jean-Philippe Godin
- Nestlé Research Center, Nestec Ltd, Vers chez les blanc, P.O. BOX 44, CH-1000 Lausanne 26, Switzerland.
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McCullagh JSO, Juchelka D, Hedges REM. Analysis of amino acid 13C abundance from human and faunal bone collagen using liquid chromatography/isotope ratio mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2006; 20:2761-8. [PMID: 16921562 DOI: 10.1002/rcm.2651] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The scope of compound-specific stable isotope analysis has recently been increased with the development of the LC IsoLink which interfaces high-performance liquid chromatography (HPLC) and isotope ratio mass spectrometry (IRMS) to provide online LC/IRMS. This enables isotopic measurement of non-volatile compounds previously not amenable to compound-specific analysis or requiring substantial modification for gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS), which results in reduced precision. Amino acids are an example of such compounds. We present a new chromatographic method for the HPLC separation of underivatized amino acids using an acidic, aqueous mobile phase in conjunction with a mixed-mode stationary phase that can be interfaced with the LC IsoLink for compound-specific delta13C analysis. The method utilizes a reversed-phase Primesep-A column with embedded, ionizable, functional groups providing the capability for ion-exchange and hydrophobic interactions. Baseline separation of 15 amino acids and their carbon isotope values are reported with an average standard deviation of 0.18 per thousand (n = 6). In addition delta13C values of 18 amino acids are determined from modern protein and archaeological bone collagen hydrolysates, demonstrating the potential of this method for compound-specific applications in a number of fields including metabolic, ecological and palaeodietary studies.
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Affiliation(s)
- James S O McCullagh
- University of Oxford, Research Laboratory for Archaeology, Dyson Perrins Building, South Parks Road, Oxford OX1 3QY, UK.
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