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Bull. Spec. CORESTA Congress, Guangzhou 1988, p. 185, S-11

HPLC determination of alkaline earth metals in tobacco

LOPEZ B.; JADRAQUE D.
Tabacalera S.A., Centro I + D/Embajadores, Madrid, Spain.
In the course of the last few years, several HPLC methods have been developed to analyse different kinds of substances in tobacco plants. However, not much attention has been given to the determination of ions by this technique. The existing methods used to determine calcium and magnesium, such as EDTA titration or atomic absorption, are susceptible to interference by other substances. This interference must be eliminated or masked prior to quantitative analysis. Thus the sample preparation process is cumbersome and time consuming. These problems are easily overcome by the HPLC technique reported here, which is not susceptible to interference. In this study, we present a simple and rapid method to determine calcium and magnesium in tobacco using HPLC. Tobacco samples (100 mg) were extracted, for 15 minutes with 100 ml of 0.01N hydrochloric acid at room temperature, and filtered through a sep-pack C-18 (Waters Associates) 50 microl of the solution were analysed chromatographically on an IC-pack C (Waters Associates) column, using EDTA buffer 0.125 mM pH4.5 as eluent, at 1.2 ml/min. Ions were detected with a Waters conductimetric detector model 430. A correlation coefficient of 0.9941 was obtained when the HPLC results were compared with those determined by EDTA titration, using calcein and Eriochrome Black-T as indicators.