Enantioselective determination of cathinones in urine by high pressure in‐line SPE–CE

Abstract

This work presents a strategy based on the in‐line coupling of SPE and CE for the chiral determination of cathinones (R,S‐mephedrone, R,S‐4‐methylephedrine, and R,S‐ methylenedioxypyrovalerone) in urine samples, using a sample pretreatment based on liquid‐liquid extraction. The chiral separation of the compounds is achieved by adding a mixture of 8 mM 2‐hydroxypropil β‐CD and 5 mM β‐CD to the BGE, which consists of 70 mM of monosodium phosphate aqueous solution at pH 2.5. Oasis HLB was the selected sorbent for the in‐line SPE device, and to reduce analysis time and LODs, several parameters affecting the in‐line SPE system were evaluated, such as pressure and time of sample injection and dimensions of the SPE device. The highest preconcentration factors were achieved by using 3 bar of injection pressure for 20 min with an in‐line SPE device of 2 mm length and 150 µm of i.d. The developed method was applied to determine the presence of the compounds in spiked urine samples. The LODs obtained were between 3 and 8 ng/mL, and these levels were below the usual concentrations at which these drugs are present in urine from cathinone abusers. Thus, the optimized method has the potential to be applied for toxicological and forensic purposes.

Advances of capillary electrophoresis enantioseparations in pharmaceutical analysis (2017–2020)

“…No significant differences between the concentrations of the methadone enantiomers in the exhaled breath condensate or the studied biological media were noted. Furthermore, CE methods were developed for the stereoselective analysis of cathinones in spiked urine [145], various phenothiazine drugs in spiked urine [146], warfarin and its 7-hydroxy metabolite in spiked urine and serum [147] as well as tramadol and methadone in spiked urine and plasma [148].…”

Potentiality of miniaturized techniques for the analysis of drugs of abuse

“…The LODs were in the range 3–8 ng/mL, quite similar to the ones achieved using LC or GC. Here, a combination of CDs (8 mM 2‐hydroxypropyl‐β‐CD and 5 mM β‐CD) was used [27]. The same compounds were also analyzed in (i) hair samples with the same system but using only β‐CD [55], (ii) postmortem blood samples [37], and (iii) biological fluid [38].…”

“…Table 1 reports selected applications by using miniaturized techniques [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44].…”

Development of a sensitive MEKC‐LIF method for synthetic cathinones analysis

“…Nevertheless, CE offers several advantages such as its drastic decrease of solvent consumption, its high efficiency, and its easiness of operation. In this context, several publications referenced CE for the enantiomeric separation of SC using cyclodextrines as chiral selector [10][11][12][13][14][15]. Recently, several preconcentration strategies were evaluated in order to reach high sensitivity for the enantiodetermination of cathinones in urine samples [16,17].…”

“…Recently, several preconcentration strategies were evaluated in order to reach high sensitivity for the enantiodetermination of cathinones in urine samples [16,17]. This research group also proposed an in-line SPE with CE-MS analysis for the enantiodetermination of R,S-3,4-methylenedioxypyrovalerone [18]. Švidrnoch et al developed a MEKC-MS/MS method for the determination of 12 SC by using the volatile ammonium salt of perfluorooctanoic acid surfactant to enhance the selectivity [19].…”