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

354 Manual of basic techniques for a health laboratoryDistilled water700mlGlycerol (C 3H 8O 3)300mlFinal pH = 7.2Dispense the solution into bijou bottles so that there is only a 2-cm gap betweenthe top of the medium and the top of the bottles. Label the bottles “BUFFEREDGLYCEROL SALINE” and write the date.Buffered water, pH 7.2 (No. 15)Buffer solution for May–Grünwald, Giemsa and Leishman stains.Disodium hydrogen phosphate (Na 2HPO 4·2H 2O) 3.8gPotassium dihydrogen phosphate (KH 2PO 4),anhydrous 2.1gDistilled waterq.s. 1000mlDissolve the salts in the distilled water, stirring well. Check the pH using narrowrangepH papers; it should be 7.0–7.2.Transfer the solution to a glass-stoppered bottle. Label the bottle “BUFFEREDWATER” and write the date.Carbol fuchsin solution for Ziehl–Neelsen stain (No. 16)Solution A (saturated solution of basic fuchsin):Basic fuchsin3 gEthanol (CH 3CH 2OH), 95%100mlSolution B (phenol aqueous solution, 50g/l (5%)):Phenol (C 6H 5OH)10gDistilled waterq.s. 200mlMix 10ml of solution A with 90ml of solution B. Transfer the resulting mixture toa glass-stoppered bottle. Label the bottle “CARBOL FUCHSIN SOLUTION”and write the date.Warning: Phenol is highly corrosive and poisonous.Cary–Blair transport medium (No. 17)Sodium thioglycolate1.5 gDisodium hydrogen phosphate (Na 2HPO 4),anhydrous1.1 gSodium chloride (NaCl)5.0 gAgar5.0 gDistilled water991.0mlAdd the salts, agar and distilled water to a clean 1000-ml beaker and mix. Heatwhile mixing until the solution becomes clear. Cool to 50 °C, add 9 ml of freshlyprepared aqueous calcium chloride (CaCl 2), 10 g/l (1%) solution, and adjust thepH to about 8.4.Dispense the solution in 7-ml volumes into previously rinsed and sterilized 9-mlscrew-capped vials. Autoclave the vials containing the media for 15 minutes, cool,and tighten the caps.Label the vials “CARY–BLAIR TRANSPORT MEDIUM” and write the date.