(19)

(11)

EP 0 317 558 A1

(12)

(43) Date of publication: 31.05.1989 Bulletin 1989/22 (21) Application number: 87904545.0 (22) Date of filing: 15.07.1987

(51) International Patent Classification (IPC):  G01N 17/ 00( . ) (86) International application number: PCT/GB1987/000500 (87) International publication number: WO 1988/001052 (11.02.1988 Gazette 1988/04)

(84) Designated Contracting States: AT BE CH DE FR IT LI LU NL SE (30) Priority: 25.07.1986 GB 19860018237 (71) Applicant: THE UNIVERSITY OF MANCHESTER INSTITUTE OF SCIENCE AND TECHNOLOGY Manchester M60 1QD (GB)	(72) Inventors: COX, William, Michael Gee Cross, Hyde heshire SK14 5LT (GB) EDEN, David, Anthony Failsworth Manchester, M35 OHF (GB) FARRELL, David, Martin Flixton Manchester, M31 3GR (GB) QUIRK, Graham, Peter Wesham, Kirkham Preston, PR4 3DJ (GB) (74) Representative: Allman, Peter John, et al  MARKS & CLERK, Sussex House, 83-85 Mosley Street Manchester M2 3LG Manchester M2 3LG (GB)