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Analytische Methoden zur Feststellung der Herkunft eines Baustoffes sind bislang kaum entwickelt worden. In Deutschland gibt es eine Reihe von Kalkiagerstätten, die in unterschiedlichen geologischen Formationen Kalk oder Dolomit enthalten. Das unterschiedliche geologische Alter von Kalken sowie die ursprüngliche mineralische Zusammensetzung und die geologische Historie spiegeln sich im 87Sr/88Sr-lsotopenverhältnis weder. Mittels der Thermionen-Massenspektrometrie kann dieses Verhältnis ermittelt und somit zur Herkunftsbestimmung eines Kalkes herangezogen werden.
Three new offset Delta11B isotope reference materials for environmental boron isotope studies
(2011)
The isotopic composition of boron is a well established tool in various areas of Science and industry. Boron isotope compositions are typically reported as 5nB values which indicate the isotopic difference of a sample relative to the isotope reference material NIST SRM 951.
A significant drawback of all of the available boron isotope reference materials is that none of them covers a natural boron isotope composition apart from NIST SRM 951. To fill this gap of required 5UB reference materials three new solution boric acid reference materials were produced, which cover 6096o of the natural boron isotope Variation (-20 to 40%oo B) of about 100%o. The new reference materials are certified for their B values and are commercially available through European Reference Materials® (http://wwrv.enn-cmi.org). The newly produced and certified boron isotope reference materials will allow straightforward method Validation and quality control of boron isotope data.
The variation of isotope abundance ratios is increasingly used to unravell natural and technical questions. In the past the investigation and interpretation of such variations was the field of a limited number of experts. With new upcoming techniques and research topics in the last decades, such as provenance and authenticity of food, the number of published isotope data strongly increased. The development of inductively coupled plasma mass spectrometers (ICPMS) from an instrument for simple quantitative analysis to highly sophisticated isotope abundance ratio machines influenced this process significantly. While in former times only experts in mass spectrometry were able to produce reproducible isotope data, nowadays many laboratories, never been in touch with mass spectrometry before, produce isotope data with an ICPMS. Especially for such user isotope reference materials (IRM) are indispensible to enable a reliable method validation. The fast development and the broad availability of ICPMS also lead to an expansion of the classical research areas and new elements are under investigation. Here all users require IRM to correct for mass fractionation or mass discrimination or at least to enable isotope data related to a common accepted basis. Despite this growing interest suitable IRM are still lacking for a number of isotope systems such as magnesium.
Development and validation of a method to determine the boron isotopic composition of crop plants
(2011)
We present a comprehensive chemical and mass spectrometric method to determine boron isotopic compositions of plant tissue. The method including dry ashing, a three-step ion chromatographic boron–matrix separation, and 11B/10B isotope ratio determinations using the Cs2BO2+ graphite technique has been validated using certified reference and quality control materials. The developed method is capable to determine δ11B values in plant tissue down to boron concentrations of 1 mg/kg with an expanded uncertainty of ≤1.7‰ (k = 2). The determined δ11B values reveal an enormous isotopic range of boron in plant tissues covering three-quarters of the natural terrestrial occurring variation in the boron isotopic composition. As the local environment and anthropogenic activity mainly control the boron intake of plants, the boron isotopic composition of plants can be used for food provenance studies.
The isotopic composition of boron is a well established tool in various areas of Science and industries. Boron isotope compositions are typically reported as 6"B values which indicate the isotopic difference of a sample relative to the internationally accepted isotope reference material NIST SRM 951. A significant drawback of all of the available boron isotope reference materials is that non covers a natural boron isotope composition apart from NIST SRM 951.
The encyclopedia of mass spectrometry, Volume 5: Elemental and isotope ratio mass spectrometry covers the subject almost entirely and serves as a reference work with links to specialist literature if more details are required.
Therefore, this book can be recommended to all beginners, students, and experts working in this broad field.
Boron isotope studies on technical materials and geological and environmental samples are one hot topic in nowadays isotope research. Provenance studies of artefacts, food and other products might become another one, as several recent studies demonstrate. Typically boron isotope determinations have been carried out by TIMS. To open up this research field to a broader scientific community we developed two analytical procedures for boron isotope determinations based on single collector SF-ICPMS combined with a sample preparation procedure consisting of dry-ashing and a three step ion chromatographic boron-matrix separation. The developed procedures consist of one low resolution (LR) and one medium resolution (MR) procedure. The repeatability for the δ11B determination in three independently measured aliquots lies between 0.2 and 0.8‰ for the LR procedure and between 0.3 and 1.5‰ for the MR procedure. The expanded uncertainties with a coverage factor of k=2 range between 1.4 and 1.6‰ for the LR procedure and between 2.9 and 3.2‰ for the MR procedure. The accuracy, expressed as average deviation from the reference values, is 0.43‰ for the LR procedure and 0.33‰ for the MR procedure. To test the practicability of the procedures the matrix tolerance has been investigated as well and was found to be up to 2 mg kg-1 of alkaline and alkaline earth elements in the final measurement solution containing 100 µg kg-1 boron. Thus a highly efficient matrix separation for SF-ICPMS boron isotope determinations is required, similar to TIMS.