The principle of the method specified is measuring the portion of the 422,7 nm line absorbed by calcium atoms and of the 285,2 nm line absorbed by magnesium atoms using a flame atomic absorption spectrometer, and comparison with the absorption produced by reference solutions. Measures the concentrations of calcium and magnesium, expressed as their oxides CaO and MgO. Applies to the analysis of extract solutions obtained from any kind of glass or glassware including laboratory and pharmaceutical ware, food and drink packaging ware, tableware and kitchenware.