Abstract

A novel analytical method based on fluorescence spectroscopy and second-order multivariate calibration was developed for the simultaneous determination of zaleplon (ZAL), zolpidem (ZOL), and zopiclone (ZOP). To the best of our knowledge, no similar strategies have been proposed for the simultaneous determination of Z-drugs. The optimal fluorescence signal was obtained in NaOH 0.1 M in acetonitrile. Excitation-emission fluorescence matrices (EEFM) were modelled using both unfolded-partial least squares -residual bilinearization (UPLS-RBL) and multivariate curve resolution-alternating least squares (MCR-ALS). UPLS-RBL achieved superior sensitivity, with detection limits in the μg L−1 range, and prediction errors below 12 %, even in the presence of unmodeled interferences. The proposed method was successfully applied to the analysis of spiked human saliva and urine samples, showing recoveries in the range of 90–125 % in both matrices and enabling reliable quantification even under substantial spectral overlap. Compared with previous approaches, the proposed EEFM/UPLS-RBL method achieved superior scores under white analytical criteria. This strategy thus offers a rapid, sensitive, and environmentally responsible alternative for the routine determination of Z-drugs in biological matrices. © 2025 Elsevier B.V.