Development of solid phase microextraction methods for the trace analyses of narcotic ADB-fubinaca and 5F-AB-fuppyca substances and explosive 2,4,6-trinitrotoluene substance in waters by using magnetic multi-walled carbon nanotube

Detection of new type psychoactive substances and explosives in wastewater and cleaning water is important in terms of clarification of crime events, determination of environmental pollution and detection of regional narcotic drug use. In this study, new methods were developed for the trace analyses of ADB-FUBINACA and 5F-AB-FUPPYCA narcotic drugs and 2,4,6-trinitrotoluene (TNT) explosive material in water by using magnetic multi-walled carbon nanotubes (m-MWCNTs) and the validation of these methods was carried out. Firstly, adsorption and desorption processes used to perform the extraction of the studied narcotic drugs and explosive substance from aqueous solution were optimized. Then, for the determination of each analyte substance extracted under optimum conditions, new detection methods were developed in a liquid chromatography-tandem mass spectrometer (LC-MS/MS) device and their validations were made. Optimum amount of magnetic adsorbent and mixing time with the help of vortex were determined to be 5 mg and 60 s, respectively, for the adsorption of each narcotic drug or explosive substance onto m-MWCNT from aqueous solutions containing ADB-FUBINACA of 1 ng mL-1, 5F-AB-FUPPYCA of 1 ng mL-1 and TNT of 3 ng mL-1. For the desorption of ADB-FUBINACA and 5F-AB-FUPPYCA from narcotic drug loaded magnetic adsorbent, optimum solvent volume and type were determined as 1 mL and ethanol, respectively, optimum mixing time with the help of vortex was found to be 60 s and optimum desorption repetition number was determined as 4 times. Optimum solvent type, solvent volume, mixing time with the help of vortex and desorption repetition number were detected to be acetone, 0.5 mL, 60 s and 4 times, respectively, to perform the desorption of TNT from explosive substance adsorbed magnetic adsorbent. In the study, ultrapure water with ammonium acetate of 10 mM and methanol were used as the mobile phase to perform the analyses of narcotic drugs and explosive substance in LC-MS/MS device and separation process was carried out by using a C18 KINETEX column (length: 10 cm, particle size: 2.6 μm and pore size: 100 Å). For the new developed methods, limit of detection (LOD) and limit of quantification (LOQ) values were calculated as 0.017 ng mL-1 and 0.056 ng mL-1 for ADB-FUBINACA, 0.035 ng mL-1 and 0.118 ng mL-1 for 5F-AB-FUPPYCA, and 0.089 ng mL-1 and 0.296 ng mL-1 for TNT, respectively. The validation of each method developed was performed. Validation results showed that the methods were selective, accurate, reproducible, and robust. In addition, the measurement uncertainties of the methods were calculated for each analyte. Finally, 1 mg of narcotic drugs and 3 mg of explosive substance were taken separately and smeared on smooth surfaces, then each of the narcotic drugs and explosive substance was transferred into water separately by wiping these substances from the surface with the help of a cloth moistened with pure water and by washing the cloth in water. The obtained aqueous solutions were extracted by using m-MWCNT and analyzed in LC-MS/MS device. The recovery values were calculated as 81.5% for ADB-FUBINACA, 72.8% for 5F-AB-FUPPYCA and 69.6% for TNT. The results obtained from this study exhibited that new methods developed can be used successfully in laboratory applications and real events.