title: Single-step total fractionation of single-wall carbon nanotubes by countercurrent chromatography.
abstract: Development of simple processes to fractionate synthetic mixtures of single-wall carbon nanotubes (SWCNTs) into individual species is crucial to many applications. Existing methods for single-chirality SWCNT purification are cumbersome, often requiring multiple steps and different conditions for different species. Here, we report a method to achieve total fractionation of a synthetic SWCNT mixture by countercurrent chromatography, resulting in purification of many single-chirality SWCNT species in a single run. This method is based on a tunable partition of sodium deoxycholate dispersed SWCNTs in a polyethylene glycol/dextran aqueous two-phase system. By running the mobile phase with 0.02% of sodium deoxycholate and a gradient of sodium dodecyl sulfate from 0.1% to 0.7% (w/w), we observe clear diameter-dependent elution, with ∼ 90% total recovery. Among all the fractions collected, a number of them are enriched in single-chirality (9,4), (7,5), (7,6), (8,3), (6,5) species, while most of the remaining ones contain no more than 2-3 major species. We also observe strong (n,m)-dependent elution peak width due to the enantiomer-resolved partition. These results demonstrate countercurrent chromatography (CCC) as an effective way to obtain high purity (n, m) species, and suggest the potential of CCC as an analytical tool for chirality distribution mapping of synthetic SWCNT mixtures.
authors.affiliation: Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology , 130 Meilong Road, Shanghai 200237, China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.forename: Constantine Y
authors.initials: CY
authors.lastname: Khripin
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Fagan
authors.forename: Peter
authors.initials: P
authors.lastname: McPhie
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Ito
authors.forename: Ming
authors.initials: M
authors.lastname: Zheng
mesh_terms: D003377:Countercurrent Distribution / Q000379:methods*; D003840:Deoxycholic Acid / Q000737:chemistry; D003911:Dextrans; D004779:Environment Design; D037742:Nanotubes, Carbon / Q000737:chemistry*; D011092:Polyethylene Glycols; D012967:Sodium Dodecyl Sulfate; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism
chemical_list: D003911:Dextrans; D037742:Nanotubes, Carbon; D003840:Deoxycholic Acid; D012967:Sodium Dodecyl Sulfate; D011092:Polyethylene Glycols