(19)

(11)

EP 0 774 114 A1

(12)

(43) Date of publication: 21.05.1997 Bulletin 1997/21 (21) Application number: 95910607.0 (22) Date of filing: 03.03.1995

(51) International Patent Classification (IPC):  G01N 27/ 12( . ) (86) International application number: PCT/GB1995/000462 (87) International publication number: WO 1995/023964 (08.09.1995 Gazette 1995/38)

(84) Designated Contracting States: AT CH DE ES FR GB IT LI NL SE (30) Priority: 03.03.1994 GB 19940004090 (71) Applicant: NEOTRONICS LIMITED Bishop's Stortford Hertfordshire CM22 6PU (GB)	(72) Inventor: McINNES, James Stevenage, Hertfordshire SG1 2NJ (GB) (74) Representative: Hedley, Nicholas James Matthew  Stephenson Harwood One, St. Paul's Churchyard London EC4M 8SH London EC4M 8SH (GB)