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. Author manuscript; available in PMC: 2014 Jan 4.
Published in final edited form as: J Chromatogr A. 2012 Nov 19;1271(1):71–85. doi: 10.1016/j.chroma.2012.11.024

Fig. 20.

Fig. 20

Separations of four pairs of (±)-DNB-amino acids by the standard analytical HSCCC technique with and without chiral selector in the stationary phase. Upper diagram was obtained using a chiral–selector-free stationary phase and the lower chromatogram using a stationary phase containing 1 g of chiral selector DPA (N-dodecanoyl-l-proline-3,5-dimethylanilide). Experimental conditions: Apparatus and column: analytical HSCCC centrifuge with a set of three multilayer coils each consisting of eleven layers of 0.85 mm ID PTFE tubing with a total capacity of ca. 60 ml; solvent system: hexane–ethylacetate–methanol–10 mM HCl (8:2:5:5, v/v) without chiral selector (upper chromatogram) and with DPA 1.6 g dissolved in 30 ml of the stationary phase (lower chromatogram); flow rate: 1 ml/min; elution mode: head to tail; sample: 10 mg each of (±)-DNB-amino acids indicated in the chromatogram dissolved in 2 ml of solvent (1 ml each phase); detection: 280 nm; revolution: 1000 rpm; (ca. 84 × g).