Available online 9 November 2022

Alp/Thp and Hyt/Thm isomers were analyzed by ion mobility.

Alp/Hyt were distinguished by [Alp/Hyt+γ-CD+Cu-H]+ with Rp-p of 1.51.

Thp/Thm was baseline separated by [Thp/Thm+γ-CD+Ca-H]+ with Rp-p of 1.96.

Quantification for the isomers was measured with internal standard.

Alp/Hyt and Thp/Thm drugs were adulteration analysis in drugs and urine.

Drug adulteration and contamination are serious threats to human health, so their accurate monitoring is very important. Allopurinol (Alp) and theophylline (Thp) are commonly used drugs for the treatment of gout and bronchitis, while their isomers hypoxanthine (Hyt) and theobromine (Thm) have no effect and affect the efficacy of the drug. In this work, the drug isomers of Alp/Hyt and Thp/Thm are simple mixing with α-, β-, γ-cyclodextrin (CD) and metal ions and separated using trapped ion mobility spectrometry-Mass spectrometry (TIMS-MS). TIMS-MS results showed that Alp/Hyt and Thp/Thm isomers can interact with CD and metal ions and form corresponding binary or ternary complexes to obtain their TIMS separation. Different metal ions and CDs shown different separation effect for the isomers, among which Alp and Hyt could be successfully distinguished by the complexes of [Alp/Hyt+γ-CD+Cu-H]+ with separation resolution (RP–P) of 1.51; whereas Thp and Thm can be baseline separated by [Thp/Thm+γ-CD+Ca-H]+ with RP–P of 1.96. Besides, chemical calculations revealed the complexes are in the inclusion forms, and microscopic interactions are somewhat different that making their mobility separation. Moreover, relative and absolute quantification were investigated with an internal standard to determine the precise isomers content, good linearity (R2>0.99) was obtained. Finally, the method was applied for the adulteration detection, that different drugs and urine were analyzed. In addition, due to the advantages of fast speed, simple operation, high sensitivity, and no chromatographic separation required, the proposed method provides an effective strategy for the drug adulteration detection of isomers.

drug isomer

adulteration

separation

ion mobility

chemical calculations

© 2022 The Author(s). Published by Elsevier B.V. on behalf of Xi’an Jiaotong University.