In the event of a nuclear crisis, involving actinides (U, Pu, Am) it is important to have fast analysis methods available in order to identify people that could be contaminated. Usually, they are performed in urine or faeces. Even though, analytical methods used with alpha detection are reliable they are lengthy and tedious to set up. This work consisted in developing an on-line coupling method between a calixarene-based chromatography column and an inductively coupled plasma mass spectrometer (ICP-MS). To do so, a speciation study of actinides in mineralised urine was developed to understand the chemical equilibria happening during the actinides extraction. A protocol was elaborated to extract simultaneously all three actinides at pH ≈ 5, then co-elute them with 0.25 mol.L-1 H3PO4. Recovery was 56 %, 74 % and 85 % for U, Pu and Am respectively. The column was then coupled to the ICPMS. A parameter study helped defining mineralisation duration, extraction and elution flow-rates. It was then possible to propose an on-line coupling system allowing reaching detection limits lower than 0.5 mBq.L-1 for 238U and 243Am and lower than 5 mBq.L-1 for 239Pu and 241Am, for analysis duration lower than 6 hours. These analytical performances show the interest of this technique for a use in a nuclear crisis situation.