RATIONALE: Carbon, hydrogen and oxygen (C, H and O) stable isotope ratios of whole wood and components are commonly used as paleoclimate proxies. In this work we consider eight different proxies in order to discover the most suitable wood component and stable isotope ratio to provide the strongest climate signal in Picea abies in a southeastern Alpine region (Trentino, Italy). METHODS: d 13 C, d 18 O and d 2 H values in whole wood and cellulose, and d 13 C and d 2 H values in lignin methoxyl groups were measured. Analysis was performed using an Isotopic Ratio Mass Spectrometer coupled with an Elemental Analyser for measuring 13 C/ 12 C and a Pyrolyser for measuring 2 H/ 1 H and 18 O/ 16 O. The data were evaluated by Principal Component Analysis, and a simple Pearson's correlation between isotope chronologies and climatic features, and multiple linear regression were performed to evaluate the data. RESULTS: Each stable isotope ratio in cellulose and lignin methoxyl differs significantly from the same stable isotope ratio in whole wood, the values begin higher in cellulose and lignin except for the lignin d 2 H values. Significant correlations were found between the whole wood and the cellulose fractions for each isotope ratio. Overall, the highest correlations with temperature were found with the d 18 O and d 2 H values in whole wood, whereas no significant correlations were found between isotope proxies and precipitation. CONCLUSIONS: d 18 O and d 2 H values in whole wood provide the best temperature signals in Picea abies in the northern Italian study area. Extraction of cellulose and lignin and analysis of other isotopic ratios do not seem to be necessary.The ANOVA shows the p values between the selected models (Model W for Cermis and Val Maggiore, Model WL for Baselga).

a b s t r a c t H, C, N, O stable isotope ratios of forage, milk and the corresponding cheese were analysed to define the isotopic characteristics of two typical mountain cheeses produced in two different terroirs with different types of vegetation. d 13C was shown to be mainly influenced by the presence of C4 plants in animal diet and, in the case of C3 plant-based forage it was below À23& varying according to the site and herbage type. d 15 N is more related to vegetation type and confirmed to be lower than þ4& for alpine products.

No abstract

Squalene and its hydrogenated derivate squalane are widely used in the pharmaceutical and cosmetic fields. The two compounds are mainly produced from the liver oil of deep sea sharks and from olive oil distillates. Squalene and squalane from shark cost less than the same compounds derived from olive oil, and the use of these shark-derived compounds is unethical in cosmetic formulations. In this work we investigate whether (13)C/(12)C and (2)H/(1)H ratios can distinguish olive oil from shark squalene/squalane and can detect the presence of shark derivates in olive oil based products. The (13)C/(12)C ratios (expressed as delta(13)C values) of bulk samples and of pure compounds measured using isotope ratio mass spectrometry (IRMS) were significantly lower in authentic olive oil squalene/squalane (N: 13; -28.4 +/- 0.5 per thousand; -28.3 +/- 0.8 per thousand) than in shark squalene/squalane samples (N: 15; -20.5 +/- 0.7 per thousand; -20.4 +/- 0.6 per thousand). By defining delta(13)C threshold values of -27.4 per thousand and -26.6 per thousand for olive oil bulk and pure squalene/squalane, respectively, illegal addition of shark products can be identified starting from a minimum of 10%. (2)H/(1)H analysis is not useful for distinguishing the two different origins. Delta(13)C analysis is proposed as a suitable tool for detecting the authenticity of commercial olive oil squalene and squalane samples, using IRMS interfaced to an elemental analyser if the purity is higher than 80% and IRMS interfaced to a gas chromatography/combustion system for samples with lower purity, including solutions of squalane extracted from cosmetic products.

No abstract