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

78 Manual of basic techniques for a health laboratoryDirty glasswarePreliminary rinsingRinse twice in cold or lukewarm water (never rinse bloodstained tubes in hotwater).If the glassware has been used for fluids containing protein, it should be rinsedimmediately and then washed (never allow it to dry before rinsing).Soaking in detergent solutionPrepare a bowl of water mixed with washing powder or liquid detergent. Put therinsed glassware in the bowl and brush the inside of the containers with a test-tubebrush (Fig. 3.57). Leave to soak for 2–3 hours.RinsingRemove the articles one by one. Rinse each one thoroughly under the tap, thensoak them all in a bowl of ordinary water for 30 minutes.Rinse each article in a stream of clean water. (Do not forget that traces of detergentleft on glassware can lead to false laboratory results.)DrainingPlace containers (beakers, flasks, measuring cylinders) on the pegs of a drainingrack. Place test-tubes upside-down in a wire basket.DryingPlace the glassware in wire baskets and dry in a hot-air oven at 60°C. Alternatively,place the baskets in a sunny spot in the laboratory and cover them with a fine cloth.PluggingThe clean dry glassware should be put away in a cupboard to protect it from dust.It is recommended that glass containers be plugged with non-absorbent cottonwool or their mouths covered with small caps made from newspaper (Fig. 3.58) or,preferably, thin sheets of paraffin wax or clinging plastic, if available.PipettesImmediate rinsingOnce a pipette has been used, rinse it immediately in a stream of cold water toremove blood, urine, serum, reagents, etc.Fig. 3.57 Cleaning dirty glasswareFig. 3.58 Plug or cover glassware toprotect it from dust