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Isotopic effects of different preservation methods on scales of olive ridley sea turtles ( Lepidochelys olivacea ) from the Mexican Central Pacific
Author(s) -
CarpenaCatoira Carla,
OrtegaOrtiz Christian D.,
ElorriagaVerplancken Fernando R.
Publication year - 2016
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.7737
Subject(s) - chemistry , isotope analysis , nitrogen , isotopes of nitrogen , dimethyl sulfoxide , preservative , liquid nitrogen , isotope , stable isotope ratio , replicate , mass spectrometry , chromatography , oceanography , food science , geology , organic chemistry , physics , quantum mechanics , statistics , mathematics
Rationale Stable isotope analysis can be used to obtain information on olive ridley sea turtles in the Mexican Central Pacific (MCP). Tissue samples such as scale, muscle, and blood are usually not analyzed immediately and are preserved in different substances such as ethanol, formalin, sodium chloride, the ideal being liquid nitrogen. Due to logistical reasons, the latter preservation method cannot always be used. The objective of the present study was to evaluate the efficiency of dimethyl sulfoxide (DMSO) as a preservation agent for later stable isotope analysis. Methods Forty‐eight paired scale samples of olive ridley were collected in MCP waters and preserved in DMSO and liquid nitrogen. We determined their δ 13 C and δ 15 N values using a Carlo Erba 1108 elemental analyzer coupled to a ThermoFinnigan Delta Plus XP isotope ratio mass spectrometer (precision ±0.2‰ for each stable isotope). The mean isotopic ratios of each preservation method were compared. Results Significant differences were observed between the isotopic ratios of samples in the two preservatives. Samples preserved in DMSO resulted in more negative isotopic values than those in liquid nitrogen, and a correction factor was calculated. The correction factors were 2.1‰ for δ 13 C values and 0.8‰ for δ 15 N values. Conclusions DMSO is not equivalent to liquid nitrogen for the preservation of olive ridley scales to be used for isotopic analysis. If DMSO has to be used for logistical reasons a replicate sample should also be collected to be able to estimate a correction factor. Copyright © 2016 John Wiley & Sons, Ltd.