Biological/Biomedical Accelerator Mass Spectrometry Targets. 2. Physical, Morphological, and Structural Characteristics

Kim, Seung Hyun; Kelly, Peter B.; Clifford, Andrew J.

doi:10.1021/ac801228t

Cited by 14 publications

(36 citation statements)

References 46 publications

(183 reference statements)

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“…In the present study, the correction curve using the graphite standard( 18 ) (GST, 14 C deficient sample, >46 600-year-old) was mass-dependent, so that the F m of the GST (Figure 1 A) was increased as carbon mass decreased, and this was consistent with prior studies. 13 , 16 The correction curve using the Ox-2 (Figure 1 B) was also mass-dependent; however, the pattern of the Ox-2 correction curve was opposite that in prior studies.…”

Section: Resultssupporting

confidence: 91%

Accelerator Mass Spectrometry Targets of Submilligram Carbonaceous Samples Using the High-Throughput Zn Reduction Method

2009

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The high-throughput Zn reduction method was developed and optimized for various biological/biomedical accelerator mass spectrometry (AMS) applications of mg of C size samples. However, high levels of background carbon from the high-throughput Zn reduction method were not suitable for sub-mg of C size samples in environmental, geochronology, and biological/biomedical AMS applications. This study investigated the effect of background carbon mass (m c ) and background 14 C level (F c ) from the high-throughput Zn reduction method. Background m c was 0.011 mg of C and background F c was 1.5445. Background subtraction, two-component mixing, and expanded formulas were used for background correction. All three formulas accurately corrected for backgrounds to 0.025 mg of C in the aerosol standard (NIST SRM 1648a). Only the background subtraction and the two-component mixing formulas accurately corrected for backgrounds to 0.1 mg of C in the IAEA-C6 and -C7 standards. After the background corrections, our high-throughput Zn reduction method was suitable for biological (diet)/biomedical (drug) and environmental (fine particulate matter) applications of sub-mg of C samples (g 0.1 mg of C) in keeping with a balance between throughput (270 samples/day/ analyst) and sensitivity/accuracy/precision of AMS measurement. The development of a high-throughput method for examination of g 0.1 mg of C size samples opens up a range of applications for 14 C AMS studies. While other methods do exist for g 0.1 mg of C size samples, the low throughput has made them cost prohibitive for many applications.Accelerator mass spectrometry (AMS) measures long-lived radioisotopes such as 14 C for geochronology, environmental, and biological/biomedical applications at attomole (amol, 10 -18 ) to zeptomole (zmol, 10 -21 ) level sensitivity, 1 which makes AMS several orders of magnitude more sensitive over liquid scintillation counting. 2-4 Preparation of carbonaceous samples for AMS involved oxidizing the carbon to CO 2 and reducing the CO 2 to graphite or graphitelike materials; the process is called "graphitization", and the prepared sample is referred to as an AMS target. The CO 2 reduction method frequently used H 2 or Zn as the reductant. 2,5-7 Biological/biomedical 14 C AMS applications were typically conducted on samples containing 1.0 mg of C for high-throughput at the expense of sensitivity. While radiocarbon dating, geo-chronology, or environmental applications of AMS were often performed on samples containing submilligram quantities of carbon (sub-mg of C), µg of C size samples were also analyzed at high sensitivity but at the expense of high throughput. 7-11 However, the high-throughput Zn reduction method using a septa-sealed vial (HT Zn reduction method in present study) were not suitable for sub-mg of C size biological/biomedical/environmental samples of AMS due to background carbon from reagents (i.e., impurities in CuO, Zn dust, Fe, or Co) 12 and/or from quartz/Pyrex glassware 12 used in graphitization.Modified graphitization method...

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Section: Resultssupporting

confidence: 91%

Accelerator Mass Spectrometry Targets of Submilligram Carbonaceous Samples Using the High-Throughput Zn Reduction Method

2009

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“…Although differences of F m between the AMS targets of GCIP (T s carbon) and GCIP (nongraphitic carbon) were not significant ( P < 0.9804), the AMS target of GCIP (T s carbon) had less accurate and precise F m value (relative error of 0.57%) than the AMS target of GCIP (nongraphitic carbon, 8,11 relative error of −0.02%) (Figure 6c). In addition, the AMS target of GCIP (T s carbon) produced an ≈40% lower 12 C − , 13 C + , and normalized 13 C + (n 13 C + ) currents ( P < 0.0001) than the AMS target of GCIP (nongraphitic carbon 8,11 ) (Figure 6d−f).…”

Section: Resultsmentioning

confidence: 95%

“…The L a of this GCIP was 4.4 nm, and the L c of this GCIP was not measurable due to its small size graphite crystallite, lack of stacking sequence/order, or both (Figure 3b). Full width half-maximum (fwhm) of D and G bands in the AMS target of GCIP in Figure 3b were 2 to 3 times broader than those in the GST(8) (Figure 3a).…”

Section: Resultsmentioning

confidence: 98%

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Quality of Graphite Target for Biological/Biomedical/Environmental Applications of ¹⁴C-Accelerator Mass Spectrometry

et al. 2010

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Catalytic graphitization for 14C-accelerator mass spectrometry (14C-AMS) produced various forms of elemental carbon. Our high-throughput Zn reduction method (C/Fe = 1:5, 500 °C, 3 h) produced the AMS target of graphite-coated iron powder (GCIP), a mix of nongraphitic carbon and Fe3C. Crystallinity of the AMS targets of GCIP (nongraphitic carbon) was increased to turbostratic carbon by raising the C/Fe ratio from 1:5 to 1:1 and the graphitization temperature from 500 to 585 °C. The AMS target of GCIP containing turbostratic carbon had a large isotopic fractionation and a low AMS ion current. The AMS target of GCIP containing turbostratic carbon also yielded less accurate/precise 14C-AMS measurements because of the lower graphitization yield and lower thermal conductivity that were caused by the higher C/Fe ratio of 1:1. On the other hand, the AMS target of GCIP containing nongraphitic carbon had higher graphitization yield and better thermal conductivity over the AMS target of GCIP containing turbostratic carbon due to optimal surface area provided by the iron powder. Finally, graphitization yield and thermal conductivity were stronger determinants (over graphite crystallinity) for accurate/precise/high-throughput biological, biomedical, and environmental14C-AMS applications such as absorption, distribution, metabolism, elimination (ADME), and physiologically based pharmacokinetics (PBPK) of nutrients, drugs, phytochemicals, and environmental chemicals.

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“…Both methods are time consuming and require an overnight combustion step to generate CO 2 from the dried sample. Kim et al investigated the graphitization process and the physical properties of the graphite [20–22]. …”

Section: Sample Preparationmentioning

confidence: 99%

Accelerator Mass Spectrometry-Enabled Studies: Current Status and Future Prospects

Arjomand

2010

Bioanalysis

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Accelerator mass spectrometry is a detection platform with exceptional sensitivity compared with other bioanalytical platforms. Accelerator mass spectrometry (AMS) is widely used in archeology for radiocarbon dating applications. Early exploration of the biological and pharmaceutical applications of AMS began in the early 1990s. AMS has since demonstrated unique problem-solving ability in nutrition science, toxicology and pharmacology. AMS has also enabled the development of new applications, such as Phase 0 microdosing. Recent development of AMS-enabled applications has transformed this novelty research instrument to a valuable tool within the pharmaceutical industry. Although there is now greater awareness of AMS technology, recognition and appreciation of the range of AMS-enabled applications is still lacking, including study-design strategies. This review aims to provide further insight into the wide range of AMS-enabled applications. Examples of studies conducted over the past two decades will be presented, as well as prospects for the future of AMS.The Ebers papyrus, written in Egypt in the 16th Century BC, lists the extensive pharmacopeia of that civilization. Included in the writings are beer, turpentine, myrrh, juniper berries, poppy, lead, salt and crushed precious stones. Also included were products derived from animals, such as lizard's blood, swine teeth and goose grease. From ancient China comes evidence of that culture's extensive efforts to heal through the use of natural products. The Pen Tsao, or Great Herbal, comprised 40 volumes describing thousands of prescriptions [1].It is curious to note that the same techniques that established the age of these written artifacts are now being used to quantify the kinetics and distribution of the pharmacopeia of this civilization. Accelerator mass spectrometry (AMS) established itself as an indispensable tool in archeology and radiocarbon dating in the 1980s. This article summarizes two decades of AMS research applied to the biomedical and pharmaceutical fields, with special focus on radiocarbon-based AMS applications.For reprint orders, please contact reprints@future-science.com. Financial & competing interests disclosureThe author is employed by Accium BioSciences, a provider of accelerator mass spectrometry services to the pharmaceutical industry, where he has stock ownership, stock options and patents pending. The author has no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties. No writing assistance was utilized in the production of this manuscript. NIH Public Access Author ManuscriptBioanalysis. Author manuscript; available in PMC 2010 November 1. Published in final edited form as:Bioanalysis. 2010 ; 2(3): 519-541. NIH-PA Author ManuscriptNIH-PA ...

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Biological/Biomedical Accelerator Mass Spectrometry Targets. 2. Physical, Morphological, and Structural Characteristics

Cited by 14 publications

References 46 publications

Accelerator Mass Spectrometry Targets of Submilligram Carbonaceous Samples Using the High-Throughput Zn Reduction Method

Accelerator Mass Spectrometry Targets of Submilligram Carbonaceous Samples Using the High-Throughput Zn Reduction Method

Quality of Graphite Target for Biological/Biomedical/Environmental Applications of ¹⁴C-Accelerator Mass Spectrometry

Accelerator Mass Spectrometry-Enabled Studies: Current Status and Future Prospects

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Biological/Biomedical Accelerator Mass Spectrometry Targets. 2. Physical, Morphological, and Structural Characteristics

Cited by 14 publications

References 46 publications

Accelerator Mass Spectrometry Targets of Submilligram Carbonaceous Samples Using the High-Throughput Zn Reduction Method

Accelerator Mass Spectrometry Targets of Submilligram Carbonaceous Samples Using the High-Throughput Zn Reduction Method

Quality of Graphite Target for Biological/Biomedical/Environmental Applications of 14C-Accelerator Mass Spectrometry

Accelerator Mass Spectrometry-Enabled Studies: Current Status and Future Prospects

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Quality of Graphite Target for Biological/Biomedical/Environmental Applications of ¹⁴C-Accelerator Mass Spectrometry