Experimental assessment of elemental analyzer isotope ratio mass spectrometry normalization methodologies for environmental stable isotopes.

Rationale: In stable isotope mass spectrometry, isotope delta values are normalized to internationally recognized reference scales using a combination of certified and in-house isotope reference materials. Numerous techniques exist for performing this normalization, but these methodologies need to be experimentally assessed to compare their effect on reproducibility of isotope results.

Methods: We tested normalization methods by the number of reference materials used, their matrix, their isotope range, and whether normalization required extrapolating beyond the isotope range.

Measurement of Adjuncts in Hard Ciders Obtainable in the United States Using Carbon Isotopes.

The carbon isotope compositions (δC values) of 23 hard ciders obtainable in the United States were analyzed to detect adjuncts, specifically added C sugars (i.e., corn syrup and cane sugar).