LC/MS (TOF) Analysis of Illicit Bath Salts in Urine on Ascentis^® Express HILIC after Solid Phase Extraction (SPE) using Supel^™-Select SCX

sample/matrix

urine samples spiked at 100 ng/mL with each target analyte (To ensure full ionization of the analytes, spiked samples were treated with formic acid to a final concentration of 0.1% formic acid.)

SPE tube/cartridge

Supel-Select SCX, 30 mg/1 mL (54240-U)

condition

1 mL 1% formic acid acetonitrile then 1 mL water

sample addition

1 mL spiked water blank or urine

washing

1 mL water, 1 mL 1% formic acid acetonitrile, 1 mL water

elution

2 mL 10% ammonium hydroxide in acetonitrile

eluate post-treatment

thoroughly mix via vortex agitation, evaporate 1 mL aliquot to dryness, reconstitute in 100 μL water:methanol

column

Ascentis Express HILIC, 10 cm x 2.1 mm I.D., 2.7 μm particles (53939-U)

mobile phase

(A) 5 mM ammonium formate acetonitrile; (B) 5 mM ammonium formate water; (98:2, A:B); premixed

flow rate

0.6 mL/min

pressure

1842 psi (127 bar)

column temp.

35 °C

detector

MS, ESI(+), TIC, m/z 100-1000

injection

1 μL

sample

200 μg/L ea. in acetonitrile