Electromembrane microextraction combined with slug flow microextraction for the analysis of narcotics in the wastewater samples followed by ion mobility spectrometry

Narcotic drugs in general have been prescribed for their painkiller effects and are known to be the most widely used analgesics for the treatment and management of moderate to intense pains. The evaluation of the concentration of these substances in biological samples is extremely essential as an aid for efficient control of medical treatment, detection of narcotic doping and abuse prevention [۱-۳]. This study exhibits for the first time a combination of the electromembrane extraction (EME) with the corona discharge ionmobility spectrometry (CD-IMS) using the slug flow microextraction (SFME) between them as a useful tandem microextraction procedure. Following the workflow, at the first step (EME), target analytes were extracted from the donor phase (DP) into the acceptor phase (AP) utilizing an electrical field. After that, the AP was collected and its pH was adjusted to be used as a DP in the subsequent step (SFME). Then, the SFME method was performed at appropriate conditions and analytes migrated to the organic solvent. Finally, the organic solvent was collected and used for the determination of narcotics by CD-IMS. This coupled method was utilized to quantify narcotics (methamphetamine, methadone, tramadol, and buprenorphine) in the wastewater samples. Box-Behnken design (BBD) and the response surface methodology (RSM) were employed for the optimization of effective factors on the extraction efficiency. Under the optimized extraction condition, good linearity was obtained in the range of ۰.۵-۷۵۰ ng/mL with coefficients of determination ≥ ۰.۹۹۱. The limit of detection and quantification were achieved in the range of ۰.۱۵–۰.۲ ng/mL and ۰.۵–۰.۷۵ ng/mL, respectively. The inter-day and intra-day precisions were not exceeding ۱۱.۵%. Also, using EME-SFME/CD-IMS system causes the enrichment factors to rise up to ۲.۷ times and the limit of detection (LOD) to decrease to ۱۵ times, compared to the EME/HPLC-UV. Finally, ۵۰ ng/mL and ۲۵۰ ng/mL of each narcotic were spiked into the wastewater samples.