▎ 摘　　要

Herein, the applicability of Mg-Al-layered double hydroxide-graphene oxide (LDH/GO) mixed-matrix membrane (MMM) for microextraction purposes is reported for the first time. The LDH/GO MMM was used as sorbent for the thin film microextraction (TFME) of diclofenac in human body fluids. The prepared LDH/GO composite has been incorporated into a mechanically stable polyvinylidene difluoride (PVDF) membrane. The contribution of GO in LDH/GO composites significantly improved the extraction efficiency of the TFME sorbent. After elution with methanol, diclofenac was quantified by high perfomance liquid chromatography-ultraviolet detection (HPLC-UV). Plackett-Burman design was used for screening the experimental factors of interest and specify the significant variables affecting the extraction efficiency. The effective factors were optimized using Box-Behnken design (BBD). Under the optimum conditions, limits of detections (LODS) were 0.14,0.23 and 0.57 mu.g L-1 in water, urine and plasma samples, respectively. Limits of quantifications (LOQs) were 0.46, 0.76 and 1.8 mu g L-1 in water, urine and plasma samples, respectively. Relative standard deviations (RSDs) at a spiked concentration of 10 mu g L-1 were 6.7.6.9 and 7.1% (as intra-day RSD) in water, urine and plasma samples, respectively. The linear dynamic ranges (LDRs) were in the range of 0.5-200 mu g L-1. The applicability of the method was investigated by the extraction and determination of diclofenac in different biological fluids including urine and plasma samples. (C) 2018 Elsevier B.V. All rights reserved.