Simultaneous Determination and Stability Analysis of Ten New Psychoactive Substances including Synthetic Cathinones, Phenethylamines, and Ketamine Substitutes in Urine Using Liquid Chromatography-Tandem Mass Spectrometry

Table 4

Matrix factor (MF) in % (range) of all analytes in urine.

Compound name	MF (50 ng/mL)		CV (%) of the IS-normalized MF
Mephedrone	94.8	[82–110]	8.6
Butylone	99.1	[92–109]	4.9
Pentylone	94.9	[90–104]	3.8
Eutylone	98.1	[86–109]	7.2
Ephylone	93.5	[86–101]	4.5
4-MEAPP	95.0	[90–104]	4.6
PMA	87.8	[82–103]	8.6
PMMA	95.5	[85–103]	5.5
DCK	93.3	[84–103]	5.1
2-FDCK	95.5	[91–99]	2.6

The CV(%) of the IS-normalized MF calculated from ten different samples of the matrix should not be greater than 15%. CV: coefficient of variation; IS: internal standard; mephedrone: 4-methylmethcathinone; ephylone: N-ethylpentylone; 4-MEAPP: 4-methyl-α-ethylaminopentiophenone; PMA: para-methoxyamphetamine; PMMA: para-methoxymethamphetamine; DCK: deschloroketamine; 2-FDCK: 2-fluorodeschloroketamine.