Manual of basic techniques for a health laboratory - libdoc.who.int

356 Manual of basic techniques for a health laboratoryDissolve the first three chemicals in the distilled water and mix. Add the detergentand mix gently. The reagent should be clear and pale yellow in colour. When measuredagainst water as blank in a spectrophotometer at a wavelength of 540nm, theabsorbance should be zero. Transfer the diluting fluid to a brown bottle. Label thebottle “DRABKIN DILUTING FLUID” and write the date. If the reagent appearscloudy, discard.Warning: Potassium cyanide is a highly poisonous chemical and should be usedonly by experienced chemists. When not in use it should be kept in a locked cupboard.After using the chemical, wash your hands thoroughly.EDTA dipotassium salt, 100g/l (10%) solution (No. 22)Dipotassium ethylenediaminetetraacetate(potassium edetate)20gDistilled waterq.s. 200mlFor use, pipette 0.04ml of this solution into small containers marked to hold 2.5mlof blood. Allow the anticoagulant to dry by leaving the containers overnight on awarm bench or in an incubator at 37°C.Eosin, 10g/l (1%) solution (No. 23)Eosin1 gDistilled waterq.s. 100mlLabel the bottle “EOSIN 1% SOLUTION” and write the date.Eosin, 20g/l (2%) solution in saline (No. 24)Eosin2 gSodium chloride (NaCl), 8.5g/l (0.85%)solution (No. 53)q.s. 100mlLabel the bottle “EOSIN 2% SOLUTION IN SALINE” and write the date.Field stain (No. 25)Field stain APreparation from prepared powdersField stain A powder5 gDistilled water, heated to 80°Cq.s. 600mlMix until dissolved. Filter when cool into a 1000-ml bottle. Label the bottle “FIELDSTAIN A” and write the date.Preparation from original stains and chemicalsMethylene blue (medicinal) 1.6gAzur 1 1.0gDisodium hydrogen phosphate (Na 2HPO 4),anhydrous 10.0gPotassium dihydrogen phosphate (KH 2PO 4),anhydrous 12.5gDistilled waterq.s. 1000mlDissolve the two salts in the distilled water. Pour about half of the solution into a1000-ml bottle containing a few glass beads. Add the stain powders and mix well.Add the remainder of the solution. Mix well and filter into a clean 1000-ml bottle.Label the bottle “FIELD STAIN A” and write the date.