A non-aqueous solid phase extraction method for alkaloid enrichment and its application in the determination of hyoscyamine and scopolamine

Abstract

A non-aqueous solid phase extraction (SPE) method utilizing silica based strong cation exchange (SCX) was developed and optimized for the enrichment of alkaloids. In this method, silica based SCX SPE columns were used for the elimination of non-alkaloid compounds and the preconcentration of alkaloids from the extracts. Mass spectrometry was employed to analyze the alkaloid-enriched fraction, and results showed that the SPE method developed in this study was effective for the removal of non-alkaloids. Then, this pretreatment method was combined with high performance liquid chromatography for the quantification of scopolamine and hyoscyamine from Scopolia tangutica Maxim. The recoveries of scopolamine and (À)-hyoscyamine were 98.51% and 91.12%, respectively. Relative standard deviation values were 1.4% for scopolamine and 1.6% for (À)-hyoscyamine. The linearity was good in the 0.01-0.8 mg mL À1 range for hyoscyamine and 0.01-0.4 mg mL À1 range for scopolamine.

Strong cation exchange column allow for symmetrical peak shape and increased sample loading in the separation of basic compounds

“…In contrast, silica adsorbents show excellent stability and flexibility to a wide range of both organic and aqueous solvents without swelling. These properties make silica-based SCX solid phase extraction cartridges quite convenient to be operated for enrichment of alkaloids from high-organic liquid extracts [19] or selective purification of basic molecules in medicinal chemistry [20]. Moreover, silica-based SCX packings offer advantages such as high mechanical strength and increased efficiency compared to polymeric materials, making them more suitable for HPLC use.…”

“…Silica-based SCX columns, either commercially available or self made, are now emerging in literatures [20][21][22]. However, the SCX mode is still adapted mostly in separations of biomacromolecules like peptides and proteins [23][24][25][26][27], and only a few used for analysis of basic drugs or alkaloids [16,[18][19][20]22,28], possibly due to low efficiency and asymmetric peak shape of bases. Furthermore, few silica-based SCX columns which allow for symmetrical peak shape and high sample loading in the chromatographic preparation of basic compounds was reported.…”

The influence of organic sample solvents on the separation efficiency of basic compounds under strong cation exchange mode

“…Using SCX to separate basic compounds offers following advantages: (i) strong retention of polar basic compounds [12,14]; (ii) quite different separation mechanism [13] from reversed phase liquid chromatography (RPLC) [15] and (iii) high selectivity between basic compounds and non-basic compounds which can be used to selectively enrich [16] or separate basic compounds [15]. Most of basic compounds are hydrophobic and always have poor solubility in aqueous solvents.…”

Scientific Opinion on Tropane alkaloids in food and feed

“…Besides the Stas-Otto procedure of multistep liquid-liquid extraction (LLE), solid phase extraction (SPE) or solid phase supported LLE on diatomaceous earth is commonly used and mixedmode SPE is applied frequently using reversed phase materials such as C18 (Papadoyannis et al, 1993), C8 or C4, together with cation exchange-material. As an alternative, a non-aqueous solid phase extraction method using strong cation exchange (SCX) SPE has been described by Long et al (2012). A recent method by Mroczek et al (2006) used pressurized liquid extraction in combination with mixedmode reversed-phase cation-exchange (MCX) SPE for the analysis of (-)-hyoscyamine, (-)-scopolamine and (-)-scopolamine-N-oxide (see Section 1.1) from plant extracts achieving recoveries of 80 to 100 % (Mroczek et al, 2006) 3.3.…”