scholarly journals Sample Dilution for AMS 14C Analysis of Small Samples (30–150 μg C)

Radiocarbon ◽  
2008 ◽  
Vol 50 (3) ◽  
pp. 413-436 ◽  
Author(s):  
M de Rooij ◽  
J van der Plicht ◽  
H A J Meijer
Keyword(s):  
Mass Spectrometry ◽  
Isotope Fractionation ◽  
Ice Core ◽  
Measurement Precision ◽  
Small Samples ◽  
Test Case ◽  
Routine Method ◽  
Optimum Conditions ◽  
Dilution Technique ◽  
Sample Dilution

We investigated sample dilution as a technique for accelerator mass spectrometry (AMS) radiocarbon analysis of very small samples (down to 30 μg). By diluting such samples up to a total weight of 200 μg, we can still perform reliable AMS measurements and improve the success rate significantly for targets that are difficult to measure. A disadvantage of this dilution technique is a loss of measurement precision. In addition, calculations of the 14C/12C isotope ratios and the uncertainties therein are not straightforward because of peculiarities in isotope fractionation processes in the AMS system. Therefore, to make sample dilution a routine method in our laboratory, we did extensive theoretical and experimental research to find the optimum conditions for all relevant parameters. Here, we report on the first detailed study dealing with all aspects of sample dilution. Our results can be applied in general. As an illustrative test case, we analyze 14C data for CO2 extracted from an ice core, from which samples of 35 μg C or less are available.

scholarly journals 14C Background Levels in An Accelerator Mass Spectrometry System

Radiocarbon ◽  
1987 ◽  
Vol 29 (3) ◽  
pp. 323-333 ◽  
Author(s):  
J S Vogel ◽  
D E Nelson ◽  
J R Southon
Keyword(s):  
Mass Spectrometry ◽  
Late Pleistocene ◽  
Accelerator Mass Spectrometry ◽  
Measurement Precision ◽  
Small Samples ◽  
Present System ◽  
Total System ◽  
The Holocene ◽  
Anthracite Coal ◽  
Mass Spectrometry System

The levels and sources of the measurement background in an AMS 14C dating system have been studied in detail. The relative contributions to the total background from combustion, graphitization, storage, handling, and from the accelerator were determined by measuring the C concentrations in samples of anthracite coal ranging in size from 15μg to 20mg. The results show that, for the present system, the uncertainty in the background is greater than that due to measurement precision alone for very old or for very small samples. While samples containing 100μg of carbon can yield useful 14C dates throughout the Holocene, 200 to 500μg are required for dating late Pleistocene materials. With the identification of the procedures that introduce contamination, the level and uncertainty of the total system background should both be reducible to the point that 100μg of carbon would be sufficient for dating most materials.

scholarly journals Radiocarbon Sample Preparation at the Circe AMS Laboratory in Caserta, Italy

Radiocarbon ◽  
2007 ◽  
Vol 49 (2) ◽  
pp. 225-232 ◽  
Author(s):  
Isabella Passariello ◽  
Fabio Marzaioli ◽  
Carmine Lubritto ◽  
Mauro Rubino ◽  
Antonio D'Onofrio ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Sample Preparation ◽  
Accelerator Mass Spectrometry ◽  
Isotope Fractionation ◽  
Background Levels

A system with several lines for the preparation of graphite targets for radiocarbon analysis has been built at the new accelerator mass spectrometry (AMS) facility in Caserta, Italy. Special attention has been paid in the design to the reduction of background contamination during sample preparation. Here, we describe the main characteristics of these preparation lines. Results of tests performed to measure 14C background levels and isotope fractionation in several blank samples with the Caserta AMS system are presented and discussed.

scholarly journals Report on the 20th International Radiocarbon Conference Graphitization Workshop

Radiocarbon ◽  
2010 ◽  
Vol 52 (3) ◽  
pp. 1230-1235 ◽  
Author(s):  
Jocelyn Turnbull ◽  
Christine Prior ◽  
Keyword(s):  
Sample Preparation ◽  
Small Samples ◽  
Background Information ◽  
Water Removal ◽  
Pressure Transducers ◽  
Pros And Cons ◽  
Short Time ◽  
Optimal Reaction ◽  
Sample Dilution ◽  
Workshop Discussion

A sample preparation workshop was convened at the 20th International Radiocarbon conference, with about 30–40 attendees. The term “sample preparation” was not further specified to allow participants to address the laboratory issues most important to them. Given the short time available, the focus quickly narrowed to details of graphite preparation for accelerator mass spectrometry (AMS), with particular interest in procedures for small samples, and hence we have changed the title to reflect the focus. Here, we summarize the workshop discussion, adding additional background information and references to publications. Several aspects of graphite preparation are included: catalyst types and ratio of catalyst to carbon; optimal reaction temperatures for various sample sizes; methods for water removal; types of pressure transducers; preconditioning of catalyst; and problems with blank values in very small samples. The pros and cons of sample dilution were also discussed.

scholarly journals Mass Spectrometry-Based Metabolomic and Proteomic Strategies in Organic Acidemias

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Esther Imperlini ◽  
Lucia Santorelli ◽  
Stefania Orrù ◽  
Emanuela Scolamiero ◽  
Margherita Ruoppolo ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Molecular Mechanisms ◽  
Propionic Acidemia ◽  
Dried Blood Spots ◽  
Small Samples ◽  
Organic Acidemias ◽  
Propionate Metabolism ◽  
Economical Evaluation ◽  
Inherited Metabolic Disorders ◽  
Recent Developments

Organic acidemias (OAs) are inherited metabolic disorders caused by deficiency of enzymatic activities in the catabolism of amino acids, carbohydrates, or lipids. These disorders result in the accumulation of mono-, di-, or tricarboxylic acids, generally referred to as organic acids. The OA outcomes can involve different organs and/or systems. Some OA disorders are easily managed if promptly diagnosed and treated, whereas, in others cases, such as propionate metabolism-related OAs (propionic acidemia, PA; methylmalonic acidemia, MMA), neither diet, vitamin therapy, nor liver transplantation appears to prevent multiorgan impairment. Here, we review the recent developments in dissecting molecular bases of OAs by using integration of mass spectrometry- (MS-) based metabolomic and proteomic strategies. MS-based techniques have facilitated the rapid and economical evaluation of a broad spectrum of metabolites in various body fluids, also collected in small samples, like dried blood spots. This approach has enabled the timely diagnosis of OAs, thereby facilitating early therapeutic intervention. Besides providing an overview of MS-based approaches most frequently used to study the molecular mechanisms underlying OA pathophysiology, we discuss the principal challenges of metabolomic and proteomic applications to OAs.

Cu isotope fractionation response to oxidative stress in a hepatic cell line studied using multi-collector ICP-mass spectrometry

2018 ◽  
Vol 410 (9) ◽  
pp. 2385-2394 ◽  
Author(s):  
María R. Flórez ◽  
Marta Costas-Rodríguez ◽  
Charlotte Grootaert ◽  
John Van Camp ◽  
Frank Vanhaecke
Keyword(s):  
Oxidative Stress ◽  
Mass Spectrometry ◽  
Cell Line ◽  
Isotope Fractionation ◽  
Hepatic Cell ◽  
Hepatic Cell Line ◽  
Icp Mass Spectrometry ◽  
Cu Isotope

scholarly journals Performance-Based Field Methods for Analyses of Substituted Phenols by Thermal Desorption Gas Chromatography/Mass Spectrometry

1996 ◽  
Vol 79 (1) ◽  
pp. 131-142 ◽  
Author(s):  
Kaisheng Jiao ◽  
Albert Robbat
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Thermal Desorption ◽  
Soil Analysis ◽  
Measurement Precision ◽  
Gas Chromatography Mass Spectrometry ◽  
Field Methods ◽  
Chromatography Mass Spectrometry ◽  
Precision And Accuracy ◽  
Soil And Water

Abstract Performance-based field methods that provide qualitative and screening level data for phenol and its substituted (chloro, methyl, and nitro) analogues were developed for soil analysis. The methods give results in under 5 min/sample. A more quantitative field method for soil and water also was developed. The method can provide data in under 20 min/sample inclusive of sample preparation. Measurement performance of thermal desorption gas chromatography/mass spectrometry (TDGC/MS) for both soil and water samples are presented. MS with selective ion monitoring and a compound-specific data analysis algorithm provides data with measurement precision and accuracy of about 40%. The more quantitative method yields data comparable with those obtained by U.S. Environmental Protection Agency standardized methods, with measurement precision and accuracy of ± 30%.

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