(19)

(11)

EP 0 862 734 A1

(12)

(43) Date of publication: 09.09.1998 Bulletin 1998/37 (21) Application number: 97937739.0 (22) Date of filing: 28.08.1997

(51) International Patent Classification (IPC):  G01N 21/ 35( . ) (86) International application number: PCT/GB1997/002329 (87) International publication number: WO 1998/010270 (12.03.1998 Gazette 1998/10)

(84) Designated Contracting States: CH DE DK ES FI FR GB IE IT LI NL PT SE (30) Priority: 04.09.1996 GB 19960018401 16.07.1997 GB 19970014922 (71) Applicant: EEV LIMITED Chelmsford, Essex, CM1 2QU (GB)	(72) Inventor: DONCASTER, Alan Mason Essex CM9 4YL (GB) (74) Representative: Cockayne, Gillian  GEC Patent Department Waterhouse Lane Chelmsford, Essex CM1 2QX Chelmsford, Essex CM1 2QX (GB)