| abstract |
PCT No. PCT/GB93/01822 Sec. 371 Date Feb. 27, 1995 Sec. 102(e) Date Feb. 27, 1995 PCT Filed Aug. 26, 1993 PCT Pub. No. WO94/04918 PCT Pub. Date Mar. 3, 1994A method of marking a liquid and subsequently detecting that the liquid has been marked, which method comprises: adding to the liquid an additive comprising a plurality of particles in an amount no greater than 1 part weight of particles per 106 parts weight liquid, the particles comprising signal means to aid their detection and not being visible in the liquid to the naked eye; sampling a portion of the liquid containing said additive, and detecting the presence of particles in the liquid, with the proviso that said signal means does not consist solely of a nucleic acid tag. |