Ion-exchange centrifugal partition chromatography: A methodological approach for peptide separation

Concentration and selective fractionation of an antihypertensive peptide from an alfalfa white proteins hydrolysate by mixed ion-exchange centrifugal partition chromatography

“…2 and Table 1). This original solution involving a stationary phase step gradient had proven to be a promising solution to enhance the selectivity in the case of delicate peptide purifications [22]. In addition, DEHPA/CaCl 2 and DEHPA/HCl molar ratios were about 10 and about 5, respectively ( Table 1).…”

“…The VW target peptide is a relatively apolar peptide (log D = −1 at pH = 6, isoelectric point = 6.09) showing physico-chemical properties close to those of the peptide model mixture tested to develop the MIXCPC process [22]. Thus, the starting conditions were a polar MtBE/CH 3 CN/n-BuOH/water (2:1:2:5, v/v) solvent system, di(2-ethylhexyl)phosphoric acid (DEHPA) as exchanger, TEA as DEHPA activator through acido-basic reaction, and two displacer carried out sequentially: Ca 2+ (CaCl 2 ) then H + (hydrochloric acid).…”

“…Thus, the starting conditions were a polar MtBE/CH 3 CN/n-BuOH/water (2:1:2:5, v/v) solvent system, di(2-ethylhexyl)phosphoric acid (DEHPA) as exchanger, TEA as DEHPA activator through acido-basic reaction, and two displacer carried out sequentially: Ca 2+ (CaCl 2 ) then H + (hydrochloric acid). DEHPA/TEA, DEHPA/CaCl 2 and DEHPA/HCl molar ratios were calculated on the basis of the optimal experimental conditions described in reference [22]. The head of the column (a quarter of the total inner volume, about 50 mL) was filled with the 3.3 DEHPA/TEA organic phase.…”

“…Then, the mixed ion-exchange centrifugal partition chromatography (MIXCPC) mode [22] was applied to the capture of the peptide of interest from the crude AWPC hydrolysate. The exchanger/peptide ratio was adjusted to improve the purification factor of VW.…”

“…Very recently, ion-exchange CPC was successfully carried out using the lipophilic di(2-ethylhexyl)phosphoric acid (DEHPA) cation-exchanger, for the purification of dipeptides within a five component model mixture [21,22]. The optimal separation conditions relied on a mixed ion exchange (MIXCPC) mode, which combined in a same experiment a strong ion-exchange process with Ca 2+ as displacer and a weak ion-exchange process with H + as displacer.…”