1. University of Trás-os-Montes and Alto Douro, P.O. Box 1013, 5001-801 Vila Real, Portugal
2. Chemistry Research Centre (CQ-VR), Department of Agronomy, School of Agrarian and Veterinary Sciences, University of Trás-os-Montes e Alto Douro, P.O. Box 1013, 5001-801 Vila Real, Portugal