(19)

(11)

EP 0 413 001 A1

(12)

(43) Date of publication: 20.02.1991 Bulletin 1991/08 (21) Application number: 89907437.0 (22) Date of filing: 19.05.1989

(51) International Patent Classification (IPC):  G01N 33/ 82( . ) (86) International application number: PCT/US1989/002193 (87) International publication number: WO 1989/012826 (28.12.1989 Gazette 1989/30)

(84) Designated Contracting States: AT BE CH DE FR GB IT LI LU NL SE (30) Priority: 15.06.1988 US 19880207139 (71) Applicant: BECKMAN INSTRUMENTS, INC. Fullerton, CA 92634 (US)	(72) Inventors: OH, Chan, S. Diamond Bar, CA 91765 (US) STONE, Linda, J. Chino, CA 91709 (US) (74) Representative: Buchan, Ian Alexander  Fitzpatricks 4 West Regent Street Glasgow G2 1RS Glasgow G2 1RS (GB)