Fast assay of glucosamine in pharmaceuticals and nutraceuticals by capillary zone electrophoresis with contactless conductivity detection
2008
Jáč, Pavel | Los, Petr | Spáčil, Zdeněk | Pospíšilová, Marie | Polášek, Miroslav
A novel capillary electrophoresis (CE) method with contactless conductivity detection suitable for the determination of glucosamine (GlAm) and K⁺ in pharmaceuticals was devised. Under the optimum conditions (aqueous 30 mM acetate buffer of pH 5.2 as the background electrolyte; voltage 30 kV; 25°C), GlAm (migrating as glucosaminium cation) was well separated from K⁺ that could occur in the dosage forms as excipient. The CE analysis was performed in fused-silica capillaries (50 μm i.d., 75 cm total length, 27 cm to detector) and the separation took <3 min. The calibration graphs were linear for both GlAm (100-300 μg/mL; r²=0.997) and K⁺ (15-75 μg/mL; r²=0.997) when using ethanolamine (100 μg/mL) as the internal standard. The LOD values (S/N=3) were 9.3 μg/mL for GlAm and 2.9 μg/mL for K⁺. The method was applied to the assay of GlAm content in various dosage forms. Intermediate precision evaluated by determining the content of GlAm in a single formulation on 3 consecutive days was characterized by RSD 2.35% (n=15). Acceptable accuracy of the CE method was confirmed by the added/found GlAm recovery experiments (recoveries 94.6-103.3%) and by statistical comparison of the results attained by the proposed CE and a reference HPLC method.
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