CRMs Column Mobile phase Acetonitrile:water Flow Rate (mL/min) Injection volume(uL) DAD (nm) Ketamine hydrochloride a 40:60* 1.5 20 210 Pethidine b 20:80** 1.0 10 210 Cocaine hydrochloride b 25:75** 1.0 5 230 Methandone hydrochloride c 80:20** 1.0 5 210 Diazepam b 30:70*** 1.0 5 230 Estazolam b 25:75*** 1.0 5 220 Heroin b 23:77** 1.0 10 210 Morphine c 15:85**** 1.0 5 210 Methamphetamine hydrochloride a 30:70* 1.5 20 210

Note: Column: a: Phenomenex Luna 5μ SCX 100A (250mm×4.6mm, 5μm); b: XTerra RP18 (150×4.6mm, 5μm); c: Platisil ODS (5 μm, 4.6mm, 250mm) *: KH2PO4, 50mmol, pH3.0; **: KH2PO4 (10mmol):KH2PO4 (10mmol)=4:5; ***: KH2PO4, 10mmol, pH3.0; ****: KH2PO4 (10mmol): Sodium 1-heptanesulfonate (5mmol):=1:1.

Table1: HPLC-DAD conditions for the studied illicit drugs.