Cation‐selective exhaustive injection and sweeping MEKC for direct analysis of methamphetamine and its metabolites in urine

Abstract

Direct analysis of methamphetamine, amphetamine, and p-hydroxymethamphetamine in urine was achieved by cation-selective exhaustive injection and sweeping micellar EKC. A bare fused-silica capillary (40 cm, 50 microm id) was filled with phosphate buffer (80 mM, pH 3, containing 20% ACN). Then a high-conductivity buffer (100 mM phosphate, pH 3; 6.9 kPa for 2.5 min) was injected. Samples were loaded using electrokinetic injection (10 kV, 600 s) which created long zones of cationic analytes. To enhance sensitivity by sweeping, the stacking step was performed using a phosphate buffer (50 mM, pH 3, containing 20% ACN and 100 mM SDS) at -20 kV before separation by MEKC. This method was capable of detecting the analytes at ppb levels. The calibration plots were linear (r(2) >or= 0.9948) over a range of 100-5000 ng/mL for methamphetamine, and 100-2000 ng/mL for amphetamine and p-hydroxymethamphetamine. The LODs (S/N = 3) were 20 ng/mL for methamphetamine, and 15 ng/mL for amphetamine and p-hydroxymethamphetamine. The method was applied to analysis of 14 urine samples of addicts and is suitable for screening suspected samples for forensic purposes. The results showed good agreement with fluorescence polarization immunoassay and GC-MS.

The interplay between trauma, substance abuse and appetitive aggression and its relation to criminal activity among high-risk males in South Africa

“…A reduction in negative emotions and an increase in the positive evaluation of violence may be reflected in the positive correlation between substance abuse and appetitive aggression. An increased lust for aggression when violence is committed under the influence of drugs may be due to drug-induced feelings of enhanced confidence and energy (Panenka et al, 2013), euphoria (Cheng, Jong, Li, Ko, & Wu, 2006) or emotions related to amusement and entertainment (Ching et al, 2012). The aforementioned beneficial effect of appetitive aggression in terms of adaptation to an adverse environment (Weierstall, Haer, Banholzer, & Elbert, 2013) may thus be enhanced by the positive features of drug or alcohol consumption (e.g.…”

A chemometric approach for the elucidation of the parameter impact in the hyphenation of field‐enhanced sample injection and sweeping in capillary electrophoresis

“…For example, some authors did not optimise the SDS concentration for the sweeping part (it is fixed according to the requirements of the MEKC separation) []. Optimisation of the HCB concentration was also not systematically performed []. Influence of the matrix conductivity was hardly investigated [].…”

CE at the omics level: Towards systems biology – An update

“…Amphetamine and p-hydroxymethamphetamine are the metabolites of methamphetamine, which is used in obesity treatment. These metabolites have been satisfactorily analyzed by cation-selective exhaustive injection and sweeping micellar EKC (MEKC) from urine samples [113]. Using another type of MEKC, nitrofuran antibiotics and metabolites have also been analyzed [114].…”