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

Annex. Reagents and their preparation 351Acetic acid, 500g/l (50%) solution (No. 3)Glacial acetic acid (CH 3COOH)100mlDistilled waterq.s. 200mlLabel the bottle “ACETIC ACID 50% SOLUTION” and write the date.Warning: Glacial acetic acid is highly corrosive.Acetone–ethanol decolorizer for Gram stain (No. 4)Acetone200mlAbsolute ethanol475mlDistilled water25mlMix the acetone, ethanol and distilled water and transfer to a clean glass-stopperedbottle. Label the bottle “ACETONE–ETHANOL DECOLORIZER” and writethe date.Acid–ethanol for Ziehl–Neelsen stain (No. 5)Hydrochloric acid (HCl), concentrated3 mlEthanol (CH 3CH 2OH), 95%97mlLabel the bottle “ACID–ETHANOL FOR ZIEHL–NEELSEN STAIN” and writethe date.Warning: Hydrochloric acid is highly corrosive.Acid reagent (No. 6)Concentrated sulfuric acid (H 2SO 4)44mlOrthophosphoric acid (H 3PO 4), 85%66mlCadmium sulfate 1.6gThiosemicarbazide50mgDistilled waterq.s. 500mlHalf fill a 500-ml flask with distilled water, add the sulfuric acid very slowly, stirringconstantly, and follow with the orthophosphoric acid. Continue mixing thesolution and add the thiosemicarbazide and then the cadmium sulfate. Make upthe volume to 500ml with distilled water. Transfer the reagent to a brown bottle.Label the bottle “ACID REAGENT” and write the date. Store at 2–8°C.The reagent will keep for at least 6 months at 2–8 °C.Warning: Sulfuric acid is highly corrosive.Albert stain (No. 7)Toluidine blue 0.15gMalachite green 0.20gGlacial acetic acid (CH 3COOH)1 mlEthanol (CH 3CH 2OH), 96%2 mlDistilled waterq.s. 100mlDissolve the glacial acetic acid in 30ml of distilled water in a clean 100-ml bottle.Add the toluidine blue and malachite green and mix well. Add the ethanol andmake up the volume to 100ml with distilled water. Mix well. Label the bottle“ALBERT STAIN” and write the date. Store at room temperature.Warning: Glacial acetic acid is highly corrosive.