1 butyl 3 (1 naphthoyl)indole 3 (1 naphthoyl) 1 pentylindole 1 Article 1 Dispersive liquid-liquid microextraction 1 Illicit drugs 1 Microextraction techniques 1 Silica C-based column 1 Synthetic cannabinoids 1 acetonitrile 1 am 694 1 cannabinoid 1 centrifugation 1 chloride 1 chlorine 1 controlled study 1 dichloromethane 1 electrospray mass spectrometry 1 illicit drug 1 ionic strength 1 jwh 019 1 jwh 200 1 jwh 250 1 limit of detection 1 liquid chromatography-mass spectrometry 1 liquid phase microextraction 1 precipitation 1 signal noise ratio 1 solvent 1 transition temperature 1 unclassified drug 1