(19)

(11)

EP 0 535 123 A1

(12)

(43) Date of publication: 07.04.1993 Bulletin 1993/14 (21) Application number: 91912113.0 (22) Date of filing: 20.06.1991

(51) International Patent Classification (IPC):  G01N 3/ 40( . ) G01N 33/ 12( . ) G01N 3/ 42( . ) (86) International application number: PCT/AU1991/000263 (87) International publication number: WO 1991/019976 (26.12.1991 Gazette 1991/29)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IT LI LU NL SE (30) Priority: 21.06.1990 AU 19900000758 (71) Applicant: JOHNSTON, Geoffrey Bega, NSW 2550 (AU)	(72) Inventor: JOHNSTON, Geoffrey Bega, NSW 2550 (AU) (74) Representative: Garratt, Peter Douglas  Mathys & Squire 100 Grays Inn Road London WC1X 8AL London WC1X 8AL (GB)