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Frank MP, Powers RW.Frank MP, et al. Among authors: powers rw.J Chromatogr B Analyt Technol Biomed Life Sci. 2007 Jun 1;852(1-2):646-9. doi: 10.1016/j.jchromb.2007.01.002. Epub 2007 Jan 13.J Chromatogr B Analyt Technol Biomed Life Sci. 2007.PMID: 17254851Free PMC article.