Capillary liquid chromatography of chlorophenoxy acid herbicides and their esters in apple juice samples after preconcentration on a cation exchanger based on polydivinylbenzene-N-vinylpyrrolidone

1. Rosales-Conrado, N.
2. León-González, M.E.
3. Pérez-Arribas, L.V.
4. Polo-Díez, L.M.