(19)

(11)

EP 0 540 584 A1

(12)

(43) Date of publication: 12.05.1993 Bulletin 1993/19 (21) Application number: 91913247.0 (22) Date of filing: 25.07.1991

(51) International Patent Classification (IPC):  G01N 25/ 68( . ) (86) International application number: PCT/GB1991/001251 (87) International publication number: WO 1992/001927 (06.02.1992 Gazette 1992/04)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IT LI LU NL SE (30) Priority: 26.07.1990 GB 19900016425 (71) Applicant: PROTIMETER PLC Marlow, Buckinghamshire SL7 1LX (GB)	(72) Inventor: DADACHANJI, Fali Minocher Buckinghamshire (GB) (74) Representative: Lesley, Sheila F., et al  FORRESTER & BOEHMERT Franz-Joseph-Strasse 38 D-80801 München D-80801 München (DE)