Method for dissolving single-particle titanite and method for determining age of single-particle titanite by(uranium-thorium)/helium dating

A method for dissolving a single-particle titanite, comprising the steps of:

• mixing the single-particle titanite, hydrofluoric acid, and a concentrated nitric acid to obtain a mixture, and subjecting the mixture to thermal digestion at 180° C. for 24 h in an autoclave, to obtain a primary dissolved sample, the concentrated nitric acid having a volume concentration of 50%;
• heating the primary dissolved sample and evaporating all liquid therein, to obtain a dry sample;
• and
• mixing the dry sample with a concentrated hydrochloric acid, and subjecting a resulting mixture to re-dissolution in an autoclave at 180° C. for 24 h, to obtain a re-dissolved sample.