Quinine sulfate monohydrate

BSA, fructose, glucose, hydrogen tetrachloroaurate (III) trihydrate (HAuCl₄·3H₂O), quinine sulfate monohydrate, sodium hydroxide (NaOH), sodium borohydride (NaBH₄), and sucrose were purchased from Sigma-Aldrich (St. Louis, MO, USA). Monobasic and dibasic sodium phosphates were purchased from J. T. Baker (Phillipsburg, NJ, USA) and thus were used to prepare sodium phosphate buffers (100 mM, pH 7.0). A Milli-Q system from Millipore (Billerica, MA, USA) was used in this study to produce ultrapure water (18.2 MΩ cm). Butylone, 4′-chloro-α-pyrrolidinopropiophenone (4′-chloro-α-PPP), 4-CMC, cocaine, dibutylone, ephylone, ethylone, heroin, ketamine, 3-methoxymethcathinone (3-MeOMC), 4-methyl-α-ethylaminopentiophenone (4-MEAPP), methamphetamine, mexedrone, and pentylone in hydrochloride salt form were acquired from actual cases.

Acetone, L-arginine, ferrocene, formaldehyde, fructose, γ-butyrolactone, glucose, 1-methyl-2-pyrrolidone, quinine sulfate monohydrate, sodium borohydride, sucrose and tetrabutyl ammonium hexafluorophosphate were purchased from Sigma Aldrich (Milwaukee, WI, USA). Monobasic and dibasic sodium phosphates obtained from J. T. Baker (Phillipsburg, NJ, USA) were used to prepare sodium phosphate buffers (100 mM, pH 7.0 and pH 11.0). A Milli-Q ultrapure water system (Millipore, Billerica, MA, USA) was used to produce ultrapure water (18.2 mΩ cm) for preparation of all aqueous solutions used in this study. Butylone, 4-chloroethcathinone, 4-chloromethcathinone, cocaine, ephedrine, ethylone, heroin, ketamine, methamphetamine and mexedrone are all in hydrochloride salt forms, which were from the Ministry of Justice Investigation Bureau, Taiwan. Their high purities were confirmed by GC–MS and NMR measurements. Chromatography paper (20 × 20 cm) was purchased from Whatman (Little Chalfont, Buckinghamshire, UK).