Determination of Ephedrine Alkaloids and Synephrine in Dietary Supplements by Column-Switching Cation Exchange High-Performance Liquid Chromatography with Scanning-Wavelength Ultraviolet and Fluorescence Detection

Abstract

An HPLC method with on-line cleanup coupled to the separation column is described for determination of (-)-norephedrine, (+)-norpseudoephedrine, (-)-ephedrine, (+)-pseudoephedrine, (-)-N-methylephedrine, (+)-N-methylpseudoephedrine, and (+/-)-synephrine in finished dietary supplement products. Test portions were extracted in acidified aqueous acetone. A filtered aliquot was cleaned up on a strong cation exchange (SCX) precolumn that later was automatically coupled to the SCX analytical column. Measurement was by full-scan UV spectra for confirmation of identity by spectral matching and real-time integration of three wavelength signals for multiple quantitation. (+/-)-Synephrine was also quantitated by native fluorescence. Recovery averaged 95-100%. Determination of the major ingredients (-)-ephedrine, (+)-pseudoephedrine, and (+/-)-synephrine compared favorably to findings by an independent LC-MS analysis for a set of 25 samples. The results of a survey were reported for total ephedrine alkaloid and synephrine content and were compared to content declaration, for approximately 48 finished products.

Simultaneous Determination of Seven Adulterants in Slimming Functional Foods by HPLC–ESI–MS/MS

“…The extraction efficiencies increased with the methanol volume used, and when the methanol volume increased to 5 mL, the recoveries of all the target chemicals except sildenafil reached 60%. Some previous studies mentioned that alkaloids could be extracted more easily by using an organic solvent such as chloroform, methanol, and some ethers in an alkaline medium (Okamura et al 1999;Dinesh et al 2002;Ai and Luo 2008;Niemann and Gay 2003). Thus different volumes of ammonia (100, 200, and 400 μL) were added into the tablet samples before methanol extraction.…”

“…The separation and detection methods include highperformance liquid chromatography-ultraviolet/diode array detector (Zhu et al 2005;Gurley et al 1998;Niemann and Gay 2003), capillary electrophoresis (CE) (Li et al 2002;Flurer et al 1995), gas chromatography-nitrogen phosphorus detector (GC/NPD) Feng et al 2004), gas chromatography-mass spectrometry (GC/MS) (Feng et al 2004), high-performance liquid chromatography-tandem mass spectrometry (Wang et al 2008;Deventer et al 2007), as well as some new analytical techniques such as ion mobility spectrometry (Gryniewicz et al 2009). Most of the methods for functional foods focused on a single substance or the substances of the analogues, such as ephedrine-type substances (Sander et al 2005;Gurley et al 1998;Niemann and Gay 2003;Flurer et al 1995), sildenafil and its analogues (Sander et al 2005;Daraghmeh et al 2001;Zhu et al 2005;Li et al 2002;Gryniewicz et al 2009;Xu and Xu 2005;Lu et al 2007), or focused on several different types of components with similar effects (Deventer et al 2007;Wang et al 2004;Feng et al 2004). Wang et al (2004) detected eight appetite suppressants, including FEN and AMF, in sliming health foods within 21 min.…”

Aplicação e avanços da espectroscopia de luminescência em análises farmacêuticas

“…As Tabelas 4 e 5 relacionam os fármacos que têm sido quantificados empregando métodos de separação como CLAE [161][162][163][164][165][166][167][168][169][170][171][172][173][174][175][176][177] (Tabela 4) e eletroforese capilar 50,[178][179][180][181] (Tabela 5) na análise de amostras complexas, como plasma e urina, ou na quantificação de misturas de fármacos e em estudos relacionados com bioequiva-lência, farmacocinêtica e biodisponibilidade. Desta forma, estas técnicas apresentam grande potencialidade de uso em situações específicas onde a matriz da amostra seja muito complexa.…”

Chemiluminescence of synephrine based on the cerium(IV)–rhodamine B system

“…Also the therapeutic importance of synephrine used as an anti-obesity treatment requires the development of a rapid, sensitive and simple analytical method for quality control and clinical monitoring. The determination of synephrine had been accomplished by different methods, such as capillary gas chromatography with diazomethane and phosgene derivatization (5) and HPLC with electrochemical (6-9), UV (10)(11)(12) and fluorescence detection (13). However, the determination of synephrine has not been investigated by chemiluminescence (CL), which forms the basis of analytical methods with the advantages of simplicity, rapidity and sensitivity of detection.…”