Identification of Bi-2-naphthol and Its Phosphate Derivatives Complexed with Cyclodextrin and Metal Ions Using Trapped Ion Mobility Spectrometry

Abstract

The separation of chiral enantiomers has gained increasing importance in many research fields, becoming a major research hotspot. 1,1′-Bi (2-naphthol) (BINOL) and 1,1′-binaphthyl-2,2′-diyl hydrogen phosphate (BNP) are referred to as atropisomer chiral molecules, which are essential chiral catalysts and intermediates in several reactions. In this work, BINOL and BNP atropisomers are separated and identified using trapped ion mobility spectrometry (TIMS) to monitor the different mobilities of their derivative complexes. The latter are obtained by the simple mixing of BINOL/BNP, cyclodextrin (CD), and the metal ions through noncovalent interactions. The results indicate that the enantiomer complexes of BINOL/BNP can be separated with a certain specificity, showing that R-, S-BINOL can be separated by the ternary complexes of [BINOL+γ-CD + Rb] + , [BINOL+γ-CD + Cu−H] + , and [BINOL+β-CD + Cu−H] + based on the difference in their mobility; similarly, the R-, S-BNP enantiomer can be isolated by the formed ternary complexes of [BNP+α-CD

Recent Advances in Separation and Analysis of Chiral Compounds

“…201,202 Chiral reference-metal ion complexes are the most commonly used derivatization reagents. Different chiral reference compounds (e.g., α-, β-, γ-CD, rifamycin and natamycin) 203,204 and metal ions (e.g., Cr 3+ , Ba 2+ , Sr 2+ , Ca 2+ , and Mn 2+ ) 205,206 were reported to achieve satisfactory separation factors. Furthermore, rigid structures in derivatization reagents or analytes are beneficial for high peak-to-peak resolution (R p-p ).…”

Simultaneous Differentiation of C═C Position Isomerism in Fatty Acids through Ion Mobility and Theoretical Calculations

“…The peak-to-peak resolution ( R p–p ) for the isomers by TIMS was calculated with eq , where A 1 is the drift value of the previous peak in two adjacent peaks, A 2 is the mobility drift data of the next peak in two adjacent peaks, and w 1 and w 2 are the respective peak widths of the two adjacent peaks.…”

“…Nonetheless, the direct separation of unsaturated fatty isomers using TIMS–MS is still challenging with similar chemical structures. However, in our previous study, the chiral isomer was directly detected by TIMS–MS through simple noncovalent interaction with a chiral reference. , We were inspired to consider whether this method could be applied to the separation and identification of fatty acid isomers. Choosing a suitable interaction reference is critical to isomer separation.…”

Ion Mobility Mass Spectrometry for the Separation and Characterization of Small Molecules

“…Apart from using chiral selectors in the separation process, the common method to increase the difference of CCS is chemical derivatization before separation. , The stereoisomers that are difficult to separate with a CCS difference of less than 2% can be distinguished by combining chemical derivatization with IM-MS. − Amino acids and oligosaccharides are the most difficult to distinguish small molecular stereoisomers, and the most commonly used chemical derivatives are metal cations and halogen anions. ,− For example, McKenna et al used 3-carboxy-5-nitrophenylboronic acid to amplify the structural difference between oligosaccharides and then used the IM-MS method to separate and identify the main products after derivatization. In order to effectively separate and quantify (+)-catechin and (−)-epicatechin, Bian et al complexed the two configurations with cyclodextrin; the difference between CCS expanded from 0.32 Å 2 to 11.75 Å 2 , and the separation degree reached 0.86 in the IM dimension after complexation.…”