The separation and identification of synthetic cathinones by portable low microflow liquid chromatography with dual capillary columns in series and dual wavelength ultraviolet detection

Abstract

This study ascertained the viability of a portable liquid chromatograph, operating at low microliter per minute flow, for the analysis of seized drugs at remote sites as well as in laboratory settings. Synthetic cathinones were screened using dual capillary columns in series, C8 and biphenyl, with on-column ultraviolet detection at 255 and 275 nm. The relative retention times of the two columns in series and their peak area absorbance ratio were used to determine if the 16 synthetic cathinones investigated could be uniquely identified in these conditions. Based on these parameters all of the analytes could be distinguished. Representative mixtures of synthetic cathinones were used to determine the repeatability, linearity, and limits of detection of the method. This cost effective and green instrumentation has the potential to satisfy minimum international guidelines for the analysis of seized drugs. K E Y W O R D S dual capillary columns in series, dual on-column UV detection, portable liquid chromatography, synthetic cathinones 3756

Recent forensic applications of enhanced chromatographic separation methods

“…May et al [28] described the use of a portable liquid chromatograph containing two capillary columns in series with dual ultraviolet (UV) detection to separate and identify synthetic cathinones. Employing a C8 column in series with a Phenyl column in combination with dual UV detection at 255 and 275 nm allowed the identification of 16 synthetic cathinones, including three sets of positional isomers.…”

“…In addition, enhanced separation methods in liquid chromatography and enhanced separation methods in supercritical fluid chromatography applicable to the forensic discipline from 2015 to 2020 will be reviewed. The applications discussed include arson investigations [13][14][15][16], environmental forensics [17,18], sexual assault investigations [19], toxicology [6,11,[20][21][22], and illicit drug analysis [5,7,8,21,[23][24][25][26][27][28].…”

Use of micro, capillary, and nano liquid chromatography for forensic analysis

“…The cost effective, low footprint, and green instrumentation described above [10,11] also has the potential to satisfy the Scientific Working Group for the Analysis of Seized Drugs (SWGDRUG) identification criteria. This is accomplished by using two capillary columns in series which give uncorrelated separations (two Category B techniques), and UV detection at two wavelengths (a potential Category C technique) [12]. In this regard, May et al [12] explored the identification of synthetic cathinones using an Axcend Focus LC Cartridge containing a 3 μm, 100 mm × 150 μm id C8 column in series with a 3 μm, 50 mm × 150 μm biphenyl column with dual on-column UV LED detection at 255 and 275 nm.…”

“…This is accomplished by using two capillary columns in series which give uncorrelated separations (two Category B techniques), and UV detection at two wavelengths (a potential Category C technique) [12]. In this regard, May et al [12] explored the identification of synthetic cathinones using an Axcend Focus LC Cartridge containing a 3 μm, 100 mm × 150 μm id C8 column in series with a 3 μm, 50 mm × 150 μm biphenyl column with dual on-column UV LED detection at 255 and 275 nm. Separations were performed at 3 μL/min employing reverse phase chromatography.…”

“…The addition of a flow controller would result in more repeatable retention times and peak areas. An overlay of the five injections for one of the synthetic cathinones mixtures was provided and is shown in Figure 2 [12].…”