(19)

(11)

EP 0 158 662 A1

(12)

(43) Date of publication: 23.10.1985 Bulletin 1985/43 (21) Application number: 84903654.0 (22) Date of filing: 05.10.1984

(51) International Patent Classification (IPC):  G01N 21/ 31( . ) G01N 33/ 18( . ) G01N 21/ 53( . ) (86) International application number: PCT/GB1984/000342 (87) International publication number: WO 1985/001579 (11.04.1985 Gazette 1985/09)

(84) Designated Contracting States: AT BE CH DE FR GB LI LU NL SE (30) Priority: 05.10.1983 GB 19830026659 (71) Applicant: UNIVERSITY OF SURREY Guildford, Surrey GU2 5XH (GB)	(72) Inventors: LLOYD, Barry, John Surrey GU2 5TH (GB) SNOOK, Martin Middlesex HA5 5BT (GB) (74) Representative: Bizley, Richard Edward, et al  BOULT, WADE & TENNANT 27 Furnival Street London EC4A 1PQ London EC4A 1PQ (GB)