OCEAN-An EXCEL add-in for O correction using a novel approximation.

In this publication, an alternative mathematical approach for correction is presented. It is shown comprehensively how the newly developed formulas are derived and what the differences are to the established algorithm recommended by Brand et al. Additionally, two simulations are presented, which demonstrate the performance (in terms of accuracy and precision) of the approach.

Evaluation of X-ray fluorescence for analysing critical elements in three electronic waste matrices: A comprehensive comparison of analytical techniques.

As the drive towards recycling electronic waste increases, demand for rapid and reliable analytical methodology to analyse the metal content of the waste is increasing, e.g. to assess the value of the waste and to decide the correct recycling routes.

An advancement of the gravimetric isotope mixture method rendering the knowledge of the spike purity superfluous.

The gravimetric isotope mixture method is the primary method to determine absolute isotope ratios. This method, however, depends on the existence of suitable spike materials and knowledge of their purities. Determining the purity of the spikes can be tedious and labour-intensive.

Combination of Standard Addition and Isotope Dilution Mass Spectrometry for the Accurate Determination of Melamine and Cyanuric Acid in Infant Formula.

In the melamine scandals of the early 2000s, different companies of the dairy industry cheated their products by applying chemical substances to feign a higher content of nitrogen. However, this had a severe toxic impact on the kidney health of consumers. As a result, tremendous effort was put into the prevention of further harm to the public.

Re-determination of R(C/C) for Vienna Peedee belemnite (VPDB).

Rationale: The isotope ratio for the internationally agreed but virtual zero-point of the carbon isotope-delta scale, Vienna Peedee belemnite (VPDB), plays a critical role in linking carbon isotope delta values to the SI. It is also a quantity used for various data processing procedures including 'O correction', clumped isotope analysis and conversion of carbon isotope delta values into other expressions of isotopic composition. A value for R(C/C) with small uncertainty is therefore desirable to facilitate these procedures.

Redefinition of the Mole in the Revised International System of Units and the Ongoing Importance of Metrology for Accurate Chemical Measurements.

This Feature highlights the role of metrology, the science of measurement, in maintaining the infrastructure we all rely on for accurate chemical measurements. In particular, the recent change to the definition of the mole, the unit of chemistry, is explained.

Investigation of mass-scale drift effects in the milli-mass range: Influence on high mass resolution mode multicollector-inductively coupled plasma mass spectrometer isotope ratio measurements.

The consequences, possible origins, and prevention of mass-scale drifts in the high mass resolution mode (HR, M/ΔM ≈ 8000) under constant conditions were investigated and simulated in case of a multicollector-inductively coupled plasma mass spectrometer (MC-ICP-MS) using silicon enriched in Si as the main element in this survey. A drifting mass scale strongly impairs the precise and accurate determination of isotope ratios, depending especially on the peak/plateau width. For example, Si in Si highly enriched in Si has an extremely small mass plateau width of ΔM ≤ 4 × 10 u, compare ΔM( Fe ) ≈ 18 × 10 u, which is to our knowledge one of the smallest plateaus routinely investigated in isotope ratio measurements, thus requiring extreme stability.

Combining Isotope Dilution and Standard Addition-Elemental Analysis in Complex Samples.

A new method combining isotope dilution mass spectrometry (IDMS) and standard addition has been developed to determine the mass fractions of different elements in complex matrices: (a) silicon in aqueous tetramethylammonium hydroxide (TMAH), (b) sulfur in biodiesel fuel, and (c) iron bound to transferrin in human serum. All measurements were carried out using inductively coupled plasma mass spectrometry (ICP-MS). The method requires the gravimetric preparation of several blends (b)-each consisting of roughly the same masses () of the sample solution (x) and of a spike solution (y) plus different masses () of a reference solution (z).

Mass Spectrometric Investigation of Silicon Extremely Enriched in (28)Si: From (28)SiF4 (Gas Phase IRMS) to (28)Si Crystals (MC-ICP-MS).

A new generation of silicon crystals even further enriched in (28)Si (x((28)Si) > 0.999 98 mol/mol), recently produced by companies and institutes in Russia within the framework of a project initiated by PTB, were investigated with respect to their isotopic composition and molar mass M(Si). A modified isotope dilution mass spectrometric (IDMS) method treating the silicon as the matrix containing a so-called virtual element (VE) existing of the isotopes (29)Si and (30)Si solely and high resolution multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) were applied in combination.

Gravimetric preparation and characterization of primary reference solutions of molybdenum and rhodium.

Gravimetrically prepared mono-elemental reference solutions having a well-known mass fraction of approximately 1 g/kg (or a mass concentration of 1 g/L) define the very basis of virtually all measurements in inorganic analysis. Serving as the starting materials of all standard/calibration solutions, they link virtually all measurements of inorganic analytes (regardless of the method applied) to the purity of the solid materials (high-purity metals or salts) they were prepared from. In case these solid materials are characterized comprehensively with respect to their purity, this link also establishes direct metrological traceability to The International System of Units (SI).

Reference measurement procedures for the iron saturation in human transferrin based on IDMS and Raman scattering.

Two reference measurement procedures are presented here that allow the determination of the iron saturation in human transferrin, based on different molecular properties. The results, directly derived from the number of ions bound to the protein molecule, are traceable to the SI. Up to now, the iron saturation has only been deduced indirectly from the amount-of-substance ratio of serum iron to transferrin in serum.

Silicon isotope ratios affected by sodium-induced broadband interference in high resolution multicollector-ICPMS.

The measurement of isotope ratios of silicon highly enriched in (28)Si ("Si28", x((28)Si) > 99.99%) is influenced by a significant interference (20%) on the (30)Si(+) signal when using a cup configuration of C ((29)Si(+)) and H3 ((30)Si(+)) on a Neptune MC-ICPMS. This interference was observed in silicon solutions with aqueous NaOH (w(NaOH) > 0.

Improving species-specific IDMS: the advantages of triple IDMS.

Triple isotope dilution mass spectrometry (triple IDMS) has been applied for the first time on protein quantification, especially on transferrin. Transferrin as an acute phase protein is a marker for several inflammation processes in the human body. Therefore, in Germany, the accurate and precise measurement of this important analyte is required.

Routine internal- and external-quality control data in clinical laboratories for estimating measurement and diagnostic uncertainty using GUM principles.

Healthcare laboratories are increasingly joining into larger laboratory organizations encompassing several physical laboratories. This caters for important new opportunities for re-defining the concept of a 'laboratory' to encompass all laboratories and measurement methods measuring the same measurand for a population of patients. In order to make measurement results, comparable bias should be minimized or eliminated and measurement uncertainty properly evaluated for all methods used for a particular patient population.

Impact of pump flow fluctuations on post column online ID-ICP-MS.

In post column online isotope dilution mass spectrometry (IDMS), the stability of the spike mass flow is a key element. Changes in viscosity or fluctuations in the pump rate of the peristaltic pump may affect the results of post column online IDMS measurements. It was shown by simulating random fluctuations and studying the changes in the resulting integrals of the isotope ratio chromatogram of the sample that even small fluctuations, observable when using peristaltic pumps, can influence the result and especially its uncertainty.

Double isotope dilution surface-enhanced Raman scattering as a reference procedure for the quantification of biomarkers in human serum.

Double isotope dilution surface-enhanced Raman scattering (double IDSERS) is qualified as a method for accurate and precise determination of biomarkers in human blood serum. Providing a full evaluation of the measurement uncertainty as well as traceability to a reference material sets the procedure in line with the requirements of a primary ratio method. Data evaluation is based on a partial least squares (PLS) model, whose prediction ability is validated from quantifying the uric acid concentration in both an artificial reference solution and a real human blood serum sample.

Alternative approach to post column online isotope dilution ICP-MS.

An alternative post column online double isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) method was developed. The resulting equation allows a straightforward calculation of the mass concentration of the analyte in the sample from the measured isotope ratio chromatogram. The use of a balance to determine and monitor the mass flow of the spike and a solution of the species under investigation as the reference are the two core components of this new method.