Figure 2.

Detection of 4-chloroethcathinone using C-dots. (a) Sensitivity for 4-chloroethcathinone at pH 11.0, and (b,c) selectivity towards 4-chloroethcathinone over other common illicit drugs and additives at pH values of (b) 11.0 and (c) 7.0. Sodium phosphate buffers (90 mM, pH 11.0 or 7.0) were used to prepare the probe solutions. The concentrations of glucose, sucrose, fructose, ephedrine, methamphetamine and 4-chloroethcathinone are all 25.0 mM, and the others are saturated. (d) Selectivity towards π-conjugated keto compounds such as 4-chloroethcathinone and other cathinone-drugs over other tested chemicals containing acetone, formaldehyde, γ-butyrolactone and 1-methyl-2-pyrrolidinone at pH values of 11.0. The concentrations of analytes are all 25.0 mM. Error bars represent standard deviations from three repeated experiments.