Application of capillary zone electrophoresis in the separation and determination of the principal gum opium alkaloids

Abstract

We describe the use of capillary zone electrophoresis (CZE) for the qualitative and quantitative determination of major alkaloids (i.e., thebaine, codeine, morphine, papavarine and narcotine) in gum opium involving the analysis of alkaloids without derivatization or purification. Three extractions with 2.5% w/v aqueous acetic acid quantitatively extracted major alkaloids. The separation was carried out by CZE using a 7:3 mixture of methanol and sodium acetate (100 mM, pH 3.1) at a potential of 15 kV, with UV detection at 224 nm. Spiking of pure reference alkaloid standards in the opium extract was used for peak identification. The influences of buffer composition, pH and voltage on the separation of alkaloids were studied. The detection limit of each alkaloid dissolved in methanol was found to be 850 ng/mL (morphine), 450 ng/mL (thebaine), 500 ng/mL (codeine), 550 ng/mL (papaverine), and 500 ng/mL (narcotine) at an injection pressure of 300 mbar (injection volume, 4 nL) with a signal-to-noise ratio of 3:1. The external standard method was used for the quantification of alkaloids. The calibration plot was based on linear regression analysis. The relative standard deviation (RSD) for peak area and migration time was in the range of 1.03-3.56% and 0.34-0.69%, respectively. Percentage compositions (g%) of opium alkaloids in five gum opium samples were found to be in the range of 14.45-15.95 (morphine), 2.0-3.45 (codeine), 1.32-2.73 (thebaine), 0.92-2.37 (papavarine), and 3.85-5.77 (narcotine). The method developed is suitable for the routine analysis of major gum opium alkaloids in samples of forensic importance.

Quality control of herbal medicines by capillary electrophoresis: Potential, requirements and applications

“…Detection and quantification of the alkaloids in two plant samples were achieved by MS in positive ESI mode, with a For the analysis of opium alkaloids a number of CE methods have been published. Beginning with Reddy et al [25], who used an aqueous ammonium acetate buffer (pH 3.1) with 70% methanol to separate morphine, papaverine, codeine, noscarpine and thebaine, followed by Collins et al [26], who utilized dynamically coated capillaries for the same purpose. They adopted a procedure previously reported by Lurie et al [27], enabling the determination of the same alkaloids in opium gum and latex in significantly reduced time of only 6.5 min.…”

A critical evaluation of high performance liquid chromatography‐electrospray ionisation‐mass spectrometry and capillary electrophoresis‐ electrospray‐mass spectrometry for the detection and determination of small molecules of significance in clinical and forensic science

“…Reddy et al [77] have applied CE to the separation and determination of the principal gum opium alkaloids such as narcotine, thebaine and papavarine without derivatisation or purification. Three extractions with 2.5% w/v aqueous acetic acid quantitatively extracted the major alkaloids.…”

Recent applications of capillary electrophoresis‐electrospray ionisation‐mass spectrometry in drug analysis

“…Reddy et al [47] have applied CE to the separation and determination of the principal gum opium alkaloids, such as narcotine, thebaine, and papavarine, without derivatisation or purification. Three extractions with 2.5% w/v aqueous acetic acid quantitatively extracted the major alkaloids.…”