(19)

(11)

EP 0 413 742 A1

(12)

(43) Date of publication: 27.02.1991 Bulletin 1991/09 (21) Application number: 89905786.0 (22) Date of filing: 26.04.1989

(51) International Patent Classification (IPC):  G01N 27/ 414( . ) G01N 33/ 487( . ) G01N 27/ 416( . ) G01N 33/ 543( . ) (86) International application number: PCT/NL1989/000029 (87) International publication number: WO 1989/010556 (02.11.1989 Gazette 1989/26)

(84) Designated Contracting States: AT BE CH DE FR GB IT LI LU NL SE (30) Priority: 26.04.1988 NL 19880001073 (71) Applicant: UNIVERSITEIT TWENTE NL-7500 AE Enschede-Drienerlo (NL)	(72) Inventors: SCHASFOORT, Richardus, Bernardus, Maria NL-7577 EP Oldenzaal (NL) GREVE, Jan NL-7576 ER Oldenzaal (NL) KOOYMAN, Rob, Peter, Herman NL-7552 GE Hengelo (NL) BERGVELD, Piet NL-7531 LJ Enschede (NL) (74) Representative: de Bruijn, Leendert C., et al  Nederlandsch Octrooibureau P.O. Box 29720 NL-2502 LS Den Haag NL-2502 LS Den Haag (NL)