irms (6)

10971365678?profile=RESIZE_400xIdentifying the extension of fruit juices with water is a great challenge. In this study, Brazilian researchers used the isotope ratio (18O/16O) as the authenticity marker for the addition of exogenous water in grape juice. The development and validation of the assay were performed using Isotope Ratio Mass Spectrometry (IRMS), and the effect of temperature and evaporation of δ18O in experimental juices was evaluated, to determine their reference values.The influence of the juice industrial production process on 18O values was verified, and commercial juices were evaluated in relation to the reference values of  the addition of water. The temperature and evaporation parameters did not influence the results of the 18O of the juice, as they presented differences lower than the method uncertainty. The heat exchanger system did not influence the proposed method either. Hence, the reference values for juice is derived from the grape musts, without affecting the interpretation of the final results. The method was tested on 30 commercial samples of whole grape juices, of which 9 had exogenous water, 3 proved to be reconstituted juices, and 18 were considered to have no exogenous water. 

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10846787662?profile=RESIZE_400xThe authenticity and origin of animal-derived foods are important for consumer information and prevention of food fraud. This review examines the current research techniques for verifying the authenticity and origin of animal-derived foods, in particular using stable isotope ratio analysis and spectroscopic techniques coupled with chemometrics. It covers meat, dairy, and seafood products, as well as honey. It also includes the new trend of analysing the inedible parts of animals to verify their origin.

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10496032473?profile=RESIZE_180x180  The Austrian Agency for Health and Food Safety (AGES) is setting up a new IRMS (Isotope Ratio Mass Spectrometry) Unit to verify the origin and authenticity of food, feed and plants. It is seeking to recruit an IRMS expert, who would:

  • Develop stable isotope mass spectrometry (IRMS) to verify the origin and authenticity of food, feed and plants,
  • Develop and optimise of IRMS methods including analysis and equipment maintenance,
  • Undertake statistical evaluations of the measurement data to assess origin and authenticity,
  • Conceive and implement of research projects,
  • Give lectures and publish scientific papers,
  • Participate in national and international working groups and cooperation networks,
  • Further develop authenticity testing in connection with other measurement techniques, in coordination with scientific findings and market requirements

 More details and application on-line at: https://jobs.ages.at/Job/179932

 

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10080705062?profile=RESIZE_400x

Organic crop production is a system requirement covering many aspects of its production. One main feature, which distinguishes organic from conventional production is the prohibition on the use of synthetic fertilisers, which are produced from atmospheric nitrogen by the Haber process, and the resulting nitrate is high in 18O and low in 15N. Isotopic measurement of nitrate extracted from plant foods can indicate which fertilisation system has been used. This requires a bacterial reduction, which is costly and can only be done by specialised laboratories. Research scientists at IAEA have developed a rapid, low-cost method to measure N and O isotope ratios using a one-step Ti(III) reduction to convert the nitrate to N2O gas for headspace isotope analysis using IRMA (isotope-ratio mass spectrometry). The new method was developed and tested using organic and conventionally grown Spanish strawberries, where the extractable nitrate N and O isotope ratios and the chemical composition were measured followed by chemometric analysis, and which revealed that the δ18O of nitrate along with δ15N and Ca2+ fully differentiated organic from conventional strawberry production. 

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6845726263?profile=RESIZE_400xIsotopic methods have been recognised by CEN (European Committee for Standardisation) and in part by the OIV (Organisation Internationale de la vigne et du vin) as a means of detecting the non-permitted presence of exogenous acetic acid and water in vinegar (CEN) and specifically wine vinegar (OIV). The methods used are EN 16466-1 for D/H in the methyl site of acetic acid [(D/H)CH3] using 2H-SNIF-NMR (Site Specific Natural Isotope Fractionation-Nuclear Magnetic Resonance), EN 16466-2 and OIV 510/2013 for analysis of 13C/12C in acetic acid (δ13C ‰) using IRMS (Isotope Ratio Mass Spectrometry), and EN 16466-3 and OIV 511/2013 for analysis of 18O/16O in water (δ18O ‰) using IRMS.

An international collaborative trial has been undertaken in 7 laboratories to define standard deviations of repeatability (sr) and reproducibility (sR) for vinegar and balsamic vinegar stable isotope ratios of H (D/H), C (δ13C) and O (δ18O), in order to establish them as fully recognised official standards. The laboratories analysed two samples of wine vinegar, one cider vinegar, and four balsamic vinegars. The results of the trial are in line with those in the literature or reported in corresponding official methods, and sr and sR of balsamic vinegar are in line with those of vinegar and must.

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The Olive Oil Marketing Regulation requires that olive oils of mixed origin have to be designated as either EU and/or non-EU origin. In this study 2H/1H, 13C/12C and 18O/16O ratios were analysed in bulk olive oils using  isotope ratio mass spectrometry (IRMS) as well as 13C/12C and 2H/1H in the four main fatty acids (linoleic, oleic, palmitic and stearic acids) using IRMS coupled with GC (gas chromatography). The isotopic composition of olive oils was successfully used to distinguish samples originating in the two areas. When bulk data were combined with fatty acid isotopic data the differentiation power of the method was improved. The improvement is due to the specific isotopic fingerprint of the individual countries making up the EU and non-EU samples. 

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