Hydrochloric acid,purified in a quartz sub-boiling still(KürnerAnalysentechnik,Rosenheim,Germany), 10 gL−1 Cs (Sigma-Aldrich,USA) and 10% (v/v) ethanol (Merck) were added to all standards and blank solutions to stabilize the solutions, in order to control ionization interferences and to simulate the wine matrix, respectively