(19)

(11)

EP 0 840 891 A1

(12)

(43) Date of publication: 13.05.1998 Bulletin 1998/20 (21) Application number: 96925015.0 (22) Date of filing: 22.07.1996

(51) International Patent Classification (IPC):  G01N 21/ 87( . ) (86) International application number: PCT/GB1996/001752 (87) International publication number: WO 1997/004303 (06.02.1997 Gazette 1997/07)

(84) Designated Contracting States: BE CH DE ES FR GB IT LI NL (30) Priority: 24.07.1995 GB 19950015144 (71) Applicant: GERSAN ESTABLISHMENT Fl-9490 Vaduz (LI)	(72) Inventor: SMITH, Martin, Phillip Wargrave, Berkshire RG10 8BB (GB) (74) Representative: Waldren, Robin Michael  MARKS & CLERK, 57-60 Lincoln's Inn Fields London WC2A 3LS London WC2A 3LS (GB)