Method for the qualitative and quantitative analysis of any type of single- or multi-element sample by optical emission spectroscopy with laser excitation, using a database produced on single-element aqueous solutions all having the same concentration of pure element, this database containing, for each element, the wavelengths of the emission lines and their respective intensity, the method comprising the following steps: - from the database, inter-element coefficients between all the elements of interest are calculated, that is to say those liable to be found together in a sample, an inter-element coefficient corresponding to the ratio between the intensities of two lines of two different elements, such a coefficient being represented by the formula: c o e f f i c i e n t i, j α / β = I i α I J β, where I i (α) and I j ( β) are the respective intensities of the line α in the element i and of the line β in the element j, these intensities coming from the database, - an analysis of the sample is carried out by optical emission spectroscopy in order to determine at least some of the various emission lines present as well as the intensities thereof, - from the emission spectrum, the elements present in the sample are determined, - the inter-element coefficients and the intensities of the lines detected are used to calculate quantitatively the respective concentrations of the various elements identified previously during the qualitative analysis, this calculation consisting of applying the following formula: c 1 + ∑ i c o e f f i c i e n t 1, i α i / β i * J i β i J 1 β i * c 1 = 100, in which c 1 represents the concentration in percentage by mass of an element in the sample chosen as the reference element, and the terms of the sum represent the concentrations of the other elements in the sample, expressed according to the concentration c 1, inter-element coefficients and intensities J i measured during the analysis of the sample. - from the database, inter-element coefficients between all the elements of interest are calculated, that is to say those liable to be found together in a sample, an inter-element coefficient corresponding to the ratio between the intensities of two lines of two different elements, such a coefficient being represented by the formula: c o e f f i c i e n t i, j α / β = I i α I J β, where I i (α) and I j ( β) are the respective intensities of the line α in the element i and of the line β in the element j, these intensities coming from the database, - an analysis of the sample is carried out by optical emission spectroscopy in order to determine at least some of the various emission lines present as well as the intensities thereof, - from the emission spectrum, the elements present in the sample are determined, - the inter-element coefficients and the intensities of the lines detected are used to calculate quantitatively the respective concentrations of the various elements identified previously during the qualitative analysis, this calculation consisting of applying the following formula: c 1 + ∑ i c o e f f i c i e n t 1, i α i / β i * J i β i J 1 β i * c 1 = 100, in which c 1 represents the concentration in percentage by mass of an element in the sample chosen as the reference element, and the terms of the sum represent the concentrations of the other elements in the sample, expressed according to the concentration c 1, inter-element coefficients and intensities J i measured during the analysis of the sample.