Development of a rapid multi-element method of analysis of antitussive syrups by inductively coupled plasma atomic emission spectrometry and direct sample introduction.

A new rapid method was developed and optimized for routine multi-element determination of traces of metals in antitussive syrups using direct introduction of diluted syrup into the nebulization system of inductively coupled plasma atomic emission spectrometer (ICP-AES). Using a Scott-type double-pass spray chamber combined with a cross-flow nebulizer, the optimum ICP conditions, like RF incident power, argon gas flow rate and nebulizer sample uptake flow rate were found. A critical objective of the study was to evaluate the matrix effect on the intensity and consequently on the sensitivity of the developed method. Thus, the maximum syrup concentration which could be introduced into the argon plasma, was estimated. The sensitivity variation was calculated as compared to the corresponding sensitivity obtained from aqueous solutions for each analyte. The performance characteristics of the proposed method were evaluated for quantitative and semi-quantitative determination and finally, the method was applied to the analysis of various commercial antitussives.