Chirality is a fundamental property in nature [1]. Although the different stereochemical configurations of one racemate can have the same physical and chemical properties, they may have different pharmacological and physiological activities [2]. In the 1950s, the occurrence of thalidomide-induced malformation events in babies sparked significant interest among researchers in the field of separation and analysis science, particularly in relation to chiral drugs [3], [4], [5], [6], [7]. Among the various separation methods, chromatographic separation is common and includes methods such as high-performance liquid chromatography (HPLC) [8], [9], [10], [11], gas chromatography (GC) [12], [13], [14], [15] and capillary electrochromatography (CEC) [16,17]. In addition, preparing a new stationary phase with good separation performance and stability is the key to chiral chromatographic columns. At present, chiral porous organic cages (POCs) [9,[18], [19], [20], [21]], chiral mesoporous silicon [22,23], chiral metal organic cages (MOCs) [6,15], chiral covalent organic frameworks (COFs) [24], [25], [26], [27], [28], [29], chiral metal organic frameworks (MOFs) [30], [31], [32], [33], [34], [35], [36] and many other chiral materials [37], [38], [39] have been reported and used as stationary phases by many researchers.

Due to the high stability, adjustable porosity, large surface area and other excellent properties of carbon materials, they have attracted wide attention in many fields, such as adsorption, biomedicine, separation and energy storage [40]. The synthesis and application of multifunctional carbon nanomaterials have been widely reported, which are synthesized by chemical etching, self-assembly, thermal decomposition and many other methods [41,42]. Therefore, carbon materials with special structures and functional groups have attracted great attention in the separation field. In particular, carbon materials with unique chiral functional groups, such as HPLC, CEC and GC, are used for chiral chromatographic separation. For example, Yuan et al. prepared ionic liquid+single-walled carbon nanotube (IL+SWNT) capillary columns for gas chromatography. The results indicated that SWNTs have wide selectivity for various organic substances, indicating that SWNTs can expand the application range to newly prepared GC stationary phases [43]. Yuan et al. also coated chiral IL stationary phases on capillary columns containing SWNTs to improve the enantioselectivity of chiral ILs. The results showed that the use of SWNTs can expand the application range of such GC chiral separation [44]. Yang et al. demonstrated that 3D graphene-based porous carbon materials (GPCM) exhibit good column reproducibility as a new stationary phase for GC, demonstrating the good potential of the GPCM stationary phase in GC analysis [45]. Qiu et al. prepared functionalized graphene quantum dot (GQD) β-cyclodextrin and cellulose silica composite materials that were applied as chiral stationary phases in HPLC, revealing the enhanced performance of GQD in chiral separation [46]. Kalugin et al. used mesoporous three-dimensional graphene nanosheets functionalized with tetracyanoethylene oxide and (S)-(+)−2-pyrrolidine methanol as the chiral stationary phase, proving the chemical stability of the pharmaceutical grade chiral separation phase of the racemic mixture of ibuprofen model and thalidomide [47]. Qiu et al. proposed a new strategy for preparing chiral porous graphene membranes from nonchiral porous graphene through mechanical stirring to induce vortex structures. Interestingly, they first observed that the front and back of the porous graphene membrane exhibited opposite optical activity and used it for enantioselective separation of DL amino acids [48]. There are few reports about chiral carbon materials used as the stationary phase for gas chromatography separation. In particular, the use of homogeneous multishelled chiral mesoporous carbon nanospheres synthesized by the spiral self-assembly of achiral precursors as stationary phases for chiral separation in GC has not been reported to our knowledge.

In this work, we used novel homogeneous multishelled mesoporous carbon nanospheres (MCNs) with a unique spiral chiral structure that were self-assembled by the lamellar micellar spiral method as the chiral stationary phase of a GC capillary column, and the chiral separation performance was evaluated (Fig. 1). It is noteworthy that the unique feature of the MCNs is that they do not use any chiral functional monomers to synthesize, but do so through the self-assembly of achiral precursors to obtain the special spiral multishelled spherical structure. In this work, in a solvent environment composed of ethanol and water, P123 (PEO20PPO70PEO20) was used as a soft template, TMB (1,3,5-trimethylbenzene) was used as a hydrophobic interaction regulator, and DA (dopamine hydrochloride) was used as a nitrogen and carbon source. The P123/TMB/DA micelle system was formed under a rotational stirring rate of 300 rpm in this reaction system, and a continuous helical polymerization micelle system was formed in the solvent through the driving force of the shearing flow. The vortex conditions formed by the system at a suitable uniform rotational speed led to the generation of nanospheres formed by rotating at a unidirectional spiral speed; therefore, the assembly driving force of the chiral nanospheres comes from the appropriate stirring rate, which is also a key mechanism for the formation of the chiral microenvironment. In addition, we verified the separation performance of the MCNs-coated column for n-alkanes, n-alcohols, esters, aromatic compounds and positional isomers, and it has a shorter analysis time and obvious separation complementarity compared with the commercial capillary column HP-5. Moreover, the thermogravimetric analysis (TGA) of this new stationary phase shows good thermal stability. In summary, the research shows that this new chiral stationary phase has good chromatographic separation performance and application prospects for GC separation.