(19)

(11)

EP 0 643 833 A1

(12)

(43) Date of publication: 22.03.1995 Bulletin 1995/12 (21) Application number: 92910780.0 (22) Date of filing: 02.06.1992

(51) International Patent Classification (IPC):  G01N 21/ 27( . ) G01N 33/ 543( . ) G01N 21/ 75( . ) G01N 33/ 548( . ) (86) International application number: PCT/GB1992/000992 (87) International publication number: WO 1992/021976 (10.12.1992 Gazette 1992/31)

(84) Designated Contracting States: BE CH DE FR GB IT LI NL SE (30) Priority: 04.06.1991 GB 19910119172 23.01.1992 GB 19920014455 (71) Applicant: FISONS plc Ipswich Suffolk IP1 1QH (GB)	(72) Inventors: BUCKLE, Philip Edward Chatteris, Cambridge PE16 6BY (GB) DAVIES, Robert John Cambridge CB5 8HS (GB) POLLARD-KNIGHT, Denise Vera St Albans AL4 0RL (GB) (74) Representative: Jones, Stephen Anthony, et al  E. N. Lewis & Taylor 144 New Walk Leicester LE1 7JA Leicester LE1 7JA (GB)