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Optimization of the derivatization procedure for the separation of the stereoisomers of 1,3-dimethylamylamine (1,3-DMAA) by gas chromatography - preliminary data
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Authors
Dias da Silva, Diana Cristina
Advisor(s)
Abstract(s)
1,3-Dimethylamylamine (1,3-DMAA),also known as methylhexanamine, is a central nervous system stimulant with structural similarities with amphetamines and therefore presenting over-lapping biological and detrimental effects [1]. Despite being banned, the presence of 1,3-DMAA in dop-ing controls and dietary supplements continues to be of significant concern. This molecule has two stere-ogenic centres and thus four stereoisomers [2]. It is widely recognized that enantiomers may exhibit dif-ferent biological activity, including pharmacokinetics, pharmacodynamics, and toxicity. Consequently, the development of analytical methods for enantioselective separation of 1,3-DMAA is crucial for an accurate determination of the risks associated with each of these stereoisomers. To develop an indirect method by gas chromatography coupled to mass spectrometry (GC-MS) for the separation and identification of the stereoisomers of the 1,3-DMAA. 1,3-DMAA was regenerated with sodium hydroxide, extracted with 0.1% triethylamine in hexane and then derivatized using the enantiomeric pure reagent (R)-(-)-α-methoxy-α-(trifluoromethyl)phenylacetyl chloride ((R)-MTPA-Cl). Subsequently, the sample was evaporated, reconstituted in anhydrous ethyl acetate, and analyzed by GC-MS. The chroma-tographic conditions were established using a capillary column containing 5% diphenyl-95% dime-thylpolysiloxane (30 m × 0.25 mm × 0.25 μm), an injector temperature set to 280 ºC, with a temperature ramp starting at 140 ºC and increasing up to 215 ºC at a flow rate of 1 mL/min to a total run of 12.32 min. Results: As preliminary data indicate, the derivatization procedure allowed the formation of 4 diastere-omers of 1,3-DMAA. The chromatographic conditions were optimised, allowing for the separation of the four diastereomers within 12 min. Derivatization and chromatographic conditions were established for enantioselective separation of 1,3-DMAA by GC-MS. Further validation of the method will be crucial for understanding the diastereomers' differential pharmacokinetics and pharmacodynamics, and consequently, the perils associated with their presence in food supplement samples.
Description
Keywords
Enantioselectivity Dietary supplements Chromatographic analysis
Pedagogical Context
Citation
Mexia-de-Almeida, M., Silva, D. D. da, Dinis-Oliveira, R. J., & Ribeiro, C. (2024). Optimization of the derivatization procedure for the separation of the stereoisomers of 1,3-dimethylamylamine (1,3-DMAA) by gas chromatography—Preliminary data. Scientific Letters, 1(Sup 1). https://doi.org/10.48797/sl.2024.230
Publisher
IUCS-CESPU Publishing