Determination of ketamine and its major metabolite, norketamine, in urine and plasma samples using microextraction by packed sorbent and gas chromatography-tandem mass spectrometry

•First MEPS-GC–MS/MS method for K and NK determination in urine and plasma samples.•Excellent quantitation limits using only 0.25mL of sample.•High recoveries for K and NK.•Suitable for regular urine and plasma analysis in the field of forensic toxicology.