## 1 Introduction  
Over the past few years, chiral analysis has attracted global attention because of the uses of chiral molecules in drug safety. Chiral molecules are essential in life processes, consisting of most biologically active compounds of living organisms [1]. Enantiomers of racenic drugs often show different behaviors in their biological activity, mechanisms, and toxicity. It is common that one enantiomer is active while other isomer is toxic in biological systems. Therefore, great emphasis should be put on the enantiomeric analysis for safe medication [2]. It was recommended that the study of enantioselective identity and stability ought to be performed before undertaking other evaluation works for drugs [2, 3]. Along with the rising analytical requirements, tremendous efforts have been devoted to searching for a high-efficiency and low-expense approach. In recent years, various methods have been applied for chiral analysis, involving high-performance liquid chromatography (HPLC), gas chromatography (GC), supercritical fluid chromatography (SFC), thin-layer chromatography (TLC), and capillary electrophoresis (CE) [3, 4]. However, these approaches share several common disadvantages, e.g., consuming too much time and needing plenty of samples. Mass spectrometry (MS) is a powerful tool for analysis owing to its strong sensitivity, high speed, and good molecular specificity [5, 6, 7]. Electrospray ionization ion trap multistage MS can provide abundant structural information for compound identification and useful stereochemical information derived from sterically controlled fragments. Thus, MS has gradually played an important role in chiral analysis. Several pure MS-based approaches have emerged by creating a chiral environment, among which the collision-induced dissociation (CID) of the diastereomeric complex method is widely used [8; 9]. In this process, normally, metal-bound trimeric clusters [M\({}^{\text{II}}\)(A)(ref)\({}_{2}\)-H]\({}^{+}\) that consist of metal ions (M\({}^{\text{II}}\)), an analyte (A), and two chiral references (ref) are formed [9].When performing a CID experiment, the relative intensities of some characteristic fragment peaks in the mass spectra facilitate differentiation between stereoisomers, and thus the chiral discrimination of two enantiomers can be achieved by measuring the chiral recognition ratio (CR method) [10; 11]. There are quantities of materials able to act as the chiral reference. During the past decades, supramolecular architectures and materials have attracted immense attention, which open the possibility of obtaining a large variety of aesthetically interesting structures and extend the applications in gas storage, sensors, separation, catalysis and others, mainly owing to their molecular recognition features. Cyclodext (CDs), composed of 6, 7, and 8 \(\alpha\)-(1-4)-linked D-glucopyranose units and shaped like a torus, represent one of the most popular supramolecules, enjoying a rather low toxicity, high aqueous solubility, and binding capacity, which exhibit wide range of utilities at reasonable price [12]. \(\beta\)-CD is the most emblematic member of this family and has been widely used in industrial and research fields, such as drug delivery and chiral selectors. In the chiral analysis field, \(\beta\)-CD and its derivatives usually act as a chiral stationary phase in various chromatographic columns, as well as mobile phase additives [13; 14]. However, it is reported many times that there is low enantioselective binding and efficiency when using \(\beta\)-CDs alone as the chiral selectors [15; 16]. Considering the low cost of the native \(\beta\)-CDs and the premises for the proven formation of specific inclusion complexes with enantiomers, their use as chiral auxiliaries in the presence of metal ions was initiated. Recently, some \(\beta\)-CDs and metal ions complex systems have been reported to enhance enantiomers separations [17].