Solvatochromic Study of Poly(vinyl chloride) Plasticizers and Their Solutions in Chloroform: Application to Phenobarbital Partitioning and Molecular Recognition of Phenobarbital

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• 作者：Jane N. Valenta ; Lifang Sun ; Yonglin Ren ; and Stephen G. Weber
• 刊名：Analytical Chemistry
• 出版年：1997
• 出版时间：September 1, 1997
• 年：1997
• 卷：69
• 期：17
• 页码：3490 - 3495
• 全文大小：179K
• 年卷期：v.69,no.17(September 1, 1997)
• ISSN：1520-6882

文摘

The possibility now exists, with the availability ofseveralfamilies of artificial molecular receptors, to createselective extraction media. More selective extractions willleadto cleaner chromatograms, with lower detection limits andperhaps higher accuracy for trace organic analysis bychromatography. Furthermore, laboratories will be expected to minimize the use of volatile organic solvents.Consequently, nonvolatile, reusable solvents will bethebasis for extractions. In addition, as artificialmolecularreceptors become more widely available, these solventswill be used to support molecular recognition. Wehavefocused on plasticizers of poly(vinyl chloride) asexamplesof these solvents. We have determined solvatochromicparameters of several plasticizers and their solutions inchloroform. These parameters, along with cohesive energy density and solvent molar volume, were used toderive linear free energy relationships for the freeenergiesof phenobarbital partitioning between solvent and aqueoussolution, receptor solubility, formation of a complex witha barbiturate receptor[1,3-bis[[[6-(1-butyrylamino)pyrid-2-yl]amino]carbonyl]benzene (2)], and thetransfer of thecomplex (artificial receptor and phenobarbital) fromchloroform to other solvents. Solventdipolarity/polarizability and hydrogen bond basicity, but not acidity, support complex dissociation. Solvents with large molarvolumes dissolve the polar solutes, phenobarbital, receptor, and complex more poorly than solvents with lowermolar volume, but there is no influence of molar volumeon complex formation.