Yoshiaki Iwamuro

Reproducible chiral capillary electrophoresis of methamphetamine and its related compounds using a chemically modified capillary having diol groups

Excellent reproducibility of chiral capillary electrophoresis for methamphetamine (MA) and its related compounds was obtained using a chemically modified capillary having diol groups. The data were compared with those using an untreated fused-silica capillary and a poly(vinyl alcohol) (PVA)-coated capillary. For five replicate analyses of a standard mixture, relative standard deviations (RSDs) of the migration times of analytes with diol or PVA-coated capillaries were less than 0.1%, which were lower than those obtained with an untreated fused-silica capillary (ca. 0.4%). The diol capillary gave reproducible migration times especially in analyses of real samples, such as crude human urine. In the analyses of five spiked urine samples, the RSD values of migration times of analytes with the diol capillary were not greater than 0.14%, which were much lower than those obtained with the PVA-coated capillary (ca. 1.5%). The proposed method was successfully used for chiral analyses of actual urine samples of MA addicts.

Characterization of the chemical diversity of glycosylated mycosporine-like amino acids in the terrestrial cyanobacterium Nostoc commune.

Mycosporine-like amino acids (MAAs) are UV-absorbing pigments, and structurally unique glycosylated MAAs are found in the terrestrial cyanobacterium Nostoc commune. In this study, we examined two genotypes of N.commune colonies with different water extract UV-absorption spectra. We found structurally distinct MAAs in each genotype. The water extract from genotype A showed a UV-absorbing spectrum with an absorption maximum at 335nm. The extract contained the following compounds: 7-O-(β-arabinopyranosyl)-porphyra-334 (478Da), pentose-bound shinorine (464Da), hexose-bound porphyra-334 (508Da) and porphyra-334 (346Da). The water extract from genotype B showed a characteristic UV-absorbing spectrum with double absorption maxima at 312 and 340nm. The extract contained hybrid MAAs (1050Da and 880Da) with two distinct chromophores of 3-aminocyclohexen-1-one and 1,3-diaminocyclohexen linked to 2-O-(β-xylopyranosyl)-β-galactopyranoside. A novel 273-Da MAA with an absorption maximum at 310nm was also identified in genotype B. The MAA consisted of a 3-aminocyclohexen-1-one linked to a γ-aminobutyric acid chain. These MAAs had potent radical scavenging activities in vitro and the results confirmed that the MAAs have multiple roles as a UV protectant and an antioxidant relevant to anhydrobiosis in N. commune. The two genotypes of N. commune exclusively produced their own characteristic glycosylated MAAs, which supports that MAA composition could be a chemotaxonomic marker for the classification of N. commune.

Differentiation of AB-FUBINACA positional isomers by the abundance of product ions using electron ionization-triple quadrupole mass spectrometry.

Mass spectrometric differentiation of structural isomers is important for the analysis of forensic samples. Presently, there is no mass spectrometric method for differentiating halogen positional isomers of cannabimimetic compounds. We describe here a novel and practical method for differentiating one of these compounds, N-(1-amino-3-methyl-1-oxobutan-2-yl)-1-(4-fluorobenzyl)-1H-indazole-3-carboxamide (AB-FUBINACA (para)), and its fluoro positional (ortho and meta) isomers in the phenyl ring by electron ionization-triple quadrupole mass spectrometry. It was found that the three isomers differed in the relative abundance of the ion at m/z 109 and 253 in the product ion spectra, while the detected product ions were identical. The logarithmic values of the abundance ratio of the ions at m/z 109 to 253 (ln(A109 /A253 )) were in the order meta < ortho < para and increased linearly with collision energy. The differences in abundances were attributed to differences in the dissociation reactivity between the indazole moiety and the fluorobenzyl group because of the halogen-positional effect on the phenyl ring. Our methodology, which is based on the abundance of the product ions in mass spectra, should be applicable to determination of the structures of other newly encountered designer drugs. Copyright

Analysis of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid and its glucuronide in urine by capillary electrophoresis/mass spectrometry

Δ(9) -Tetrahydrocannabinol is the primary psychoactive component in cannabis, one of the most commonly used illicit drugs in the world. This paper describes a simple and rapid method for direct analysis of major metabolites of Δ(9) -tetrahydrocannabinol; 11-nor-Δ(9) -tetrahydrocannabinol-9-carboxylic acid and its glucuronide in urine by capillary electrophoresis/mass spectrometry. The only pretreatment needed for a urine sample was dilution with methanol containing an internal standard and centrifugation. Electrophoresis was carried out in an untreated fused-silica capillary (50 µm i.d. × 85 cm) filled with 40 m m ammonium formate (pH 6.4). An analysis could be completed within 10 min. For both compounds, the assay was linear over the range 0.1-10 µg/mL in urine with correlation coefficients (r(2) ) >0.99 and the limit of detection was 0.5 pg (10 nL injection). The detection yields and reproducibilities were determined at three different concentrations (0.1, 0.5 and 2 µg/mL in urine). The mean detection yields were 60-99%. The intra- and inter-day relative standard deviations of migration times were 0.063-0.19 and 0.18-0.36%, and those of peak areas were 4.2-18 and 5.9-25%, respectively. The proposed method successfully analyzed the urine samples of cannabis users.

Differentiation of AB-FUBINACA and its five positional isomers using liquid chromatography–electrospray ionization-linear ion trap mass spectrometry and triple quadrupole mass spectrometry

PurposePositional isomer differentiation is crucial for forensic analysis. The aim of this study was to differentiate AB-FUBINACA positional isomers using liquid chromatography (LC)–electrospray ionization (ESI)-linear ion trap mass spectrometry (LIT-MS) and LC–ESI-triple quadrupole mass spectrometry (QqQ-MS).MethodsAB-FUBINACA, its two fluorine positional isomers on the phenyl ring, and three methyl positional isomers in the carboxamide side chain were analyzed by LC–ESI-LIT-MS and LC–ESI-QqQ-MS.ResultsFour of the positional isomers, excluding AB-FUBINACA and its 3-fluorobenzyl isomer, were chromatographically separated on an ODS column in isocratic mode. ESI-LIT-MS could discriminate only three isomers, i.e., the 2-fluorobenzyl isomer, the N-(1-amino-2-methyl-1-oxobutan-2-yl) isomer, and the N-(1-amino-1-oxobutan-2-yl)-N-methyl isomer, based on their characteristic product ions observed at the MS3 stage in negative mode. ESI-QqQ-MS differentiated all six isomers in terms of the relative abundances of the product ions that contained the isomeric moieties involved in collision-induced dissociation reactions. The six isomers were more clearly and significantly differentiated upon comparison of the logarithmic values of the product ion abundance ratios as a function of collision energy.ConclusionsThe present LC–MS methodologies were useful for the differentiation of a series of AB-FUBINACA positional isomers.

Molecularly imprinted polymer solid-phase extraction of synthetic cathinones from urine and whole blood samples

In forensic drug analysis, extractive pretreatment is required prior to instrumental analysis to ensure successful detection of the target compounds. However, conventional extraction methods such as hydrophilic polymer-based solid-phase extraction and liquid-liquid extraction are unsuitable for an emerging class of new psychoactive substances, namely, synthetic cathinones, because they exhibit a lack of class selectivity and increased risk of target analyte decomposition during extraction. To address these issues, we describe a highly class-selective sample clean-up method for the extraction of synthetic cathinones from urine and whole blood samples, exploiting a molecularly imprinted polymer solid-phase extraction cartridge. In terms of the influence of the synthetic cathinone molecular structure on the extraction recovery, we showed that while longer alkyl side chains slightly reduced the extraction efficiency, substituent variation on the aromatic ring exerted no effect. Molecularly imprinted polymer solid-phase extraction of 11 synthetic cathinones from urine samples yielded higher recoveries than the two conventional extraction methods, and smaller matrix effect was observed than that with hydrophilic polymer-based solid-phase extraction. Molecularly imprinted polymer solid-phase extraction from whole blood samples gave recoveries comparable to those of urine samples. Therefore, the proposed method is applicable for the extraction and quantitative determination of synthetic cathinones in biological samples.

Postmortem detection of rocuronium and sugammadex by LC/MS in the blood of a patient who died on postoperative day 8

PurposeThis case report describes the purposeful forensic detection of both the muscle relaxant rocuronium and the reversal agent sugammadex in the blood of a patient who died 8 days after surgery.MethodsThe two compounds were analyzed by liquid chromatography/mass spectrometry (LC/MS).ResultsThe molar concentrations of the two compounds were almost the same, indicating that rocuronium had lost its muscle relaxant effect, because rocuronium and sugammadex formed a 1:1 complex in the blood due to their high affinities.ConclusionsWhen a muscle relaxant is detected in a forensic sample, the presence of its reversal agent should also be investigated.

Highly Sensitive Detection of Organophosphorus Pesticides Using 5,10,15,20-Tetrakis(4-hydroxyphenyl)porphyrin

We describe a unique UV-visible absorption spectral property of 5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin (THPP) in the presence of organophosphorus (OP) pesticides. Upon titrating each 16 among total 40 different OP pesticides, the Soret band was significantly red-shifted, and a very intense Q band appeared. They were attributed to the diprotonation of THPP. A suitable solvent for this reaction was determined to be methanol. THPP would become a potential sensor molecule used to detect OP pesticides with high sensitivity in the concentration range of 10(-6) - 10(-4) M.