Application of nanofiber‐packed SPE for determination of salivary‐free cortisol using fluorescence precolumn derivatization and HPLC detection |
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| Authors: | Li‐Qin Chen Xue‐Jun Kang Jing Sun Jian‐Jun Deng Zhong‐Ze Gu Zu‐Hong Lu |
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| Affiliation: | 1. Key Laboratory of Child Development and Learning Science (Ministry of Education), Research Center for Learning Science, Southeast University, Nanjing, P. R. China;2. Lab of Environment and Biosafety, Research Institute of Southeast University in Suzhou, Dushu Lake Higher Education Town, Suzhou, P. R. China;3. State Key Laboratory of Molecular and Biomolecular Electronics, Southeast University, Nanjing, P. R. China |
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| Abstract: | Salivary cortisol has emerged as an easy‐to‐collect biologic marker of stress in many researches. In this study, we present a method for the determination of salivary‐free cortisol using HPLC method with fluorescence precolumn derivatization, which is based on a novel extraction from the strongly acidic medium (fluorescent derivatives of cortisol in sulfuric acid medium) by electrospun polystyrene nanofibers packed SPE. For high‐throughput sample extraction, an array pretreatment device based on nanofibers packed SPE micro‐column was designed. The LOD of cortisol was 0.01 μg/L (S/N=3). The RSDs (n=6) for all analytes were below 8.0%, and the recoveries were 110, 102.4, and 99.4% (n=3) for saliva spiked with 0.1, 10, and 20 μg/L of cortisol, respectively. The proposed method was then successfully applied in the determination of free cortisol in human saliva. The salivary cortisol concentrations in the real samples ranged from 0.22 to 7.45 μg/L. The nanofiber‐packed SPE overcame the low extraction recovery and bad clean‐up effect of the conventional methods, and increased the sensitivity and selectivity of the method. |
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| Keywords: | Cortisol Electrospun polystyrene nanofiber Extraction Saliva Sulfuric acid |
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