Open tubular CEC with novel block copolymer coatings for separation of aromatic amines

Abstract

A new type of block copolymer, which was synthesized by styrene and maleic anhydride, P(MAn-alt-St) 119 -b-PSt 558 , was successfully developed as the capillary coatings in open tubular CEC. It is interesting that the covalently bonded coatings are porous and the coatings can play the role of surfactants in the separation of aromatic amines when the buffer solution was composed of 30.0 mM ammonium acetate at pH 7.7 with 20% THF. Thus, successful baseline separation of five kinds of aromatic amines has been achieved. As validated by both artificially prepared solutions of aromatic amines and four real samples of commercially available permanent hair dyes, this proposed method was successfully applicable to the quantitative analysis of p-phenylenediamine (PPD) and ophenylenediamine (OPD) ingredients in these commercial products, with a linear range between 8.3 mM and 6.0 mM, correlation coefficient above 0.990 and recovery between 83.5 and 110.9%. The detection limit obtained from calculations based on signal-to-noise ratio (S/N 5 3) was 4.2 mM for PPD and 6.0 mM for OPD, respectively. Furthermore, the role of the surfactants played by the block copolymer coatings has been primarily explored.

A well‐defined block copolymer serving as surfactants in separation of 1,4‐dihydropyridines by open‐tubular capillary eletrochromatography

“…Thus, combining the specific feature of block copolymers with the obvious merits of OT‐CEC can provide a promising method in separation science. Increasing evidences have demonstrated that the well separation performances of block copolymer coatings have been achieved based on their self‐assembly properties [] because the block copolymer coatings could play a similar role as surfactants MEKC. Thus, OT‐CEC with block copolymer coatings is an alternative choice to MEKC.…”

“…Also, several other kinds of block copolymers have been synthesized in our laboratory for the separation of raw material and product in Baylis Hillman reaction, aromatic amines as well as steroids via self‐assembly of copolymers into micelles []. However, some of those block copolymers were physically coated in capillary with low reproducibility compared with covalent coating [] and great attention has been focused on one specific copolymer rather than one series. Thus, it is essential to investigate one series of covalent copolymer coatings to get further insight into the separation mechanism.…”

Stable neutral double hydrophilic block copolymer capillary coating for capillary electrophoretic separations

“…On the first day the EOF was +1.23 × 10 −2 /Vs ( n = 5) and from the second day to the eighth day the EOF varied between +2.8 × 10 −10 and +5.8 × 10 −10 m 2 /Vs ( n = 5), and then it started to increase stepwise proving that the coating can be used only during the first 8 days. Although permanent coatings prepared from block copolymers can be stable even for 2–3 months, their coating processes include time‐consuming steps and harsh conditions . Semipermanent coatings prepared from block copolymers can have lifetimes up to 40 h and over 30 consecutive runs , but the EOF is suppressed only by one magnitude.…”

Tunable thick porous silica coating fabricated by multilayer-by-multilayer bonding of silica nanoparticles for open-tubular capillary chromatographic separation

“…In order to resolve this shortcoming, some approaches including sol-gel-derived phases [7,8], etching [8,9], porous layers [10][11][12][13][14][15][16][17][18][19][20], and nanoparticle phases [21][22][23][24][25][26][27][28] have been developed to increase the surface area of the OT columns. Since polymer based materials can provide a thick coating and can be formed relative easily, most of the published works were focused on fabricating a coating onto capillary column via a polymerization reaction [29].…”