| abstract |
A dry multilayer element for assaying salicylate comprises a) a spreading layer; b) a reagent layer comprising salicylate hydroxylase, (NADH), tyrosinase and a hydrazone coupling agent, wherein c) the hydrazone and the salicylate hydroxylase are in separate zones of the reagent layer separated by a barrier zone that prevents passage of molecules having a molecular weight greater than 5,000; d) the zone in which the hydrazone coupling agent is located has a pH greater than 6.5 and; e) the hydrazone is water insoluble at a pH above 6.5. s |