Liquid chromatography-mass spectrometry method development for monitoring stress-related corticosteroids levels in pig saliva.

Ledicia Rey-Salgueiro, Elena Martínez-Carballo, Jesús Simal-Gándara

Index: J. Chromatogr. B. Analyt. Technol. Biomed. Life Sci. 990 , 158-63, (2015)

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Abstract

Biochemical response stressors results in an increase of adrenocortical activity. Before knowing the corticosteroid levels in saliva in a stressful situation, baselines salivary levels should be established. A method for simultaneous determination of five corticosteroids was developed, validated and applied to pig saliva at farms. The method employs solid-phase extraction (SPE) coupled with clean-up extraction step using silica cartridge in the same step followed by liquid chromatography/tandem mass spectrometry (LC-MS/MS), using electrospray ionization (ESI) in positive mode. The overall method quantification limits range from 0.050 to 0.30μg/L for the enrichment of 1.0mL saliva samples and analyte recoveries are between 60 and 90% (RSD<11%). Some factors studied were: pig sex, breeds, and time at farm. The analytical method clearly shows that CRL and CRS levels of, respectively, 3.0 and 4.0μg/L in saliva can be indicative of maxima non-stress levels in different pig breeds at farm. Copyright © 2015 Elsevier B.V. All rights reserved.