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We report a case of seized methamphetamine (MA) samples showing unique drug profiles. Conventional drug profiling such as impurity profiling and chiral analysis as well as stable isotope ratio mass spectrometry (IRMS) was performed on seven MA-HCl samples. The results of impurity profiling suggested that the samples were synthesized by reductive amination. The high enantiomeric purities of the samples suggested that the samples were optically resolved. The d 13 C and d 15 N values gave different grouping patterns from conventional drug profiling. This is the first case report of the use of IRMS with seized MA samples presumptively synthesized by reductive amination.

Temperature-responsive chromatography, in which the characteristics of the stationary phase can be controlled by varying the column temperature with only an aqueous eluent, was applied to the analysis of psychoactive drugs. Temperature-responsive poly(N-isopropylacrylamide) (PNIPAAm)-based copolymers were synthesized with n-butyl methacrylate (BMA) and N-acryloyl L-phenylalanine methyl ester (Phe-OMe) as a comonomer. These polymers were grafted onto aminopropyl silica and used as the stationary phase. Seven psychoactive drugs could be separated simultaneously by the column, including BMA. Among the seven drugs, for triazolam, which has a triazole ring in its structure, the order of elution changed on changing the column temperature. The phenomenon could be explained by NH-π interactions between the NH groups of PNIPAAm and π electrons of the triazole ring. The conformational changes of PNIPAAm altered the degree of exposure of the NH groups and would affect the elution order of the analytes. To enhance the molecular recognition ability for the triazole ring, the column containing Phe-OMe was used. Noticeable changes in the retention factors occurred due to the additional π-π interactions between the phenyl moieties of Phe-OMe and the triazole ring. The effects of the π-π interactions were also altered by the changes in column temperature. This chromatographic system, which needs no toxic organic solvent, offers an effective way to determine the causes of addiction in medical institutions.

A novel and simple method that combines an online concentration technique with an enantioseparation technique for capillary electrophoresis-namely, cation-selective exhaustive injection and sweeping cyclodextrin-modified micellar electrokinetic chromatography (CSEI-sweeping CD-modified MEKC)-realizes the effective enantioseparation of cationic analytes while keeping a significant increase of detection sensitivity. This technique consists of a slight modification of the basic CSEI-sweeping MEKC. The main idea is to simply add an anionic CD as a chiral selector into the micellar buffer including sodium dodecyl sulfate, but not to change any other buffers in order to preserve the online concentration mechanism. When applied to analysis of the street drug, methamphetamine, the method achieved not only a baseline enantioseparation but also limits of detection (LODs; S/N = 3) of 70-90 pg/mL (ppt) for each isomer. This translates to a more than 10 000-fold improvement compared to the LODs by the usual injection method. The present technique, which was made from a slight modification of CSEI-sweeping MEKC, would give an attractive approach that is applicable to almost any analytes for which CSEI-sweeping MEKC is applicable; all that is required is the selection of an appropriate anionic CD to be added to the micellar buffer.