(19)

(11)

EP 0 538 380 A1

(12)

(43) Date of publication: 28.04.1993 Bulletin 1993/17 (21) Application number: 91913524.0 (22) Date of filing: 28.06.1991

(51) International Patent Classification (IPC):  A01N 57/ 26( . ) A01N 57/ 30( . ) (86) International application number: PCT/US1991/004450 (87) International publication number: WO 1992/000673 (23.01.1992 Gazette 1992/03)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IT LI LU NL SE (30) Priority: 11.07.1990 US 19900551121 (71) Applicant: E.I. DU PONT DE NEMOURS AND COMPANY Wilmington Delaware 19898 (US)	(74) Representative: Jones, Alan John, et al  CARPMAELS & RANSFORD 43 Bloomsbury Square London, WC1A 2RA London, WC1A 2RA (GB)