Direct Methods

Applying either y-cyclodextrin (y-CD) or Cu(II) salts together with N2-S-(N2-.R-)2'-hydroxypropyl-S-

phenylalanineamide as CMA is very time-consuming (Figure 7A): the separation of three AA pairs requires more than 2 h. Thus, CMAs can be regarded as an inferior approach in the chiral recognition of AA enantiomers, due to the need for a continuous supply of the often expensive CMA and to the disadvantageous chromatographic conditions. Bonded N2-S-(N2-.R -)2'-hydroxypropyl-S-phenylalanine-amide, CSP, allows the comparison of the CMA and CSP protocols for the same enantiomer separations. The CSP method resolved four pairs of

Figure 7 LC separation of AA enantiomers. (A) Enantiomeric separation of a mixture of three dansyl AAs. (Reproduced with permission from Marcelli R etal. (1996) Chirality 8: 452.) (B) Separation of 37 phenylthiocarbamyl AAs. (Reproduced with permission from Iida T etal. (1997) Analytical Chemistry 69: 4463.) (C) Aminogram of fir honey derivatized with (a) OPA/IBLC and (b) OPA/IBDC. (Reproduced with permission from Bruckner H et al. (1995) JournalofChromatography 697: 229.)

Figure 7 LC separation of AA enantiomers. (A) Enantiomeric separation of a mixture of three dansyl AAs. (Reproduced with permission from Marcelli R etal. (1996) Chirality 8: 452.) (B) Separation of 37 phenylthiocarbamyl AAs. (Reproduced with permission from Iida T etal. (1997) Analytical Chemistry 69: 4463.) (C) Aminogram of fir honey derivatized with (a) OPA/IBLC and (b) OPA/IBDC. (Reproduced with permission from Bruckner H et al. (1995) JournalofChromatography 697: 229.)

Figure 7 Continued

Figure 7 Continued dansylated AAs within 30 min, attesting to the superiority of CSP over CMA. Recently, the elut-ion of the PTC AAs on a new CSP (Figure 7B) permitted the partial separation of 18 AA pairs within 150 min.

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Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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