Laboratory safety techniques
Pipette
Do not pipette hazardous liquids by using mouth suction to fill pipette. Use pipette fillers or rubber tubing connected through trap to vacuum line for this purpose.
Wet oxidation
This technique is among the most hazardous uses of acids but can be performed safely. Observe precautions for particular acid used and rigorously follow directions given in specific method being used.
Safe handling of acids
Use effective acid-resistant fume removal device whenever heating acids or performing reactions, which liberate acid fumes. In diluting, always add acid to water unless otherwise directed in method. Keep acids off skin and protect eyes from spattering. If acids are spilled on skin, wash immediately with large amounts of water.
Acetic acid and acetic anhydride
React vigorously or explosively with CrO heavy rubber gloves when using and other strong oxidizers. Wear face shield and
Chromic and perchromic acid
Can react explosively with acetic anhydride, acetic acid, ethyl acetate, isoamyl alcohol and benzaldehyde. Less hazardous with ethylene glycol, glycerol and methanol. Conduct reactions behind safety barrier. Wear face shield and heavy rubber gloves.
Nitric acid
Reacts vigorously and explosively with aniline, H S, flammable solvents, hydrazine and metal powders (especially, Zn, Al and Mg). Gaseous nitrogen oxides from HNO can cause severe lung damage. Copious fumes are evolved when concentrated HNO and concentrated HCl are mixed. Avoid premixing. Use effective fume removal device when fumes are generated. Handle with disposable polyvinyl chloride gloves.
Oxalic acid
Forms explosive compound with silver (Ag) and mercury (Hg). Oxalates are toxic. Avoid skin contact and ingestion.
Perchloric acid
Contact with oxidizable or combustible materials or with dehydrating or reducing agents may result in fire or explosion. Persons using this acid should thoroughly familiar with its hazards. Safety practices should include the following:
• Remove spilled HClO by immediate and through washing with large amounts of water.
• Hoods, ducts and other devices for removing HClO vapours should be made of chemically inert materials and so designed that they can be thoroughly washed with water. Exhaust systems should discharge in safe location and fan should be accessible for cleaning.
• Avoid use of organic chemicals in hoods or other fume removal devices used for HClO digestions.
• Use goggles, barrier shields and other devices as necessary for personal protection; use polyvinyl chloride, not rubber, gloves
• In wet combustions with HClO , treat sample first with HNO to destroy easily oxidizable organic matter unless otherwise specified. Do not evaporate to dryness. |
• Contact of HClO solution with strong dehydrating agents such as P O or concentrated H SO may result in the formation of anhydrous HClO , which reacts explosively with organic matter and with reducing agents.
Sulphuric acid
Always add H SO to H O. Wear face shield and heavy rubber gloves to protect against splashes.
Fuming acids
Prepare and use with effective fume removal device. Wear acid-resistant gloves and eye protection.
Safe handling of alkalis
Alkalis can burn skin, eye and respiratory tract severely. Wear heavy rubber gloves and face shield to protect against concentrated alkali liquids. Use effective fume removal device or gas mask to protect respiratory tract against alkali dusts and vapours.
Ammonia
Extremely caustic liquid and gas. Wear skin, eye and respiratory protection when handling in anhydrous or gaseous state. NH vapours are flammable. React vigorously with strong oxidizing agents, halogens and strong acids.
Ammonium hydroxide
Caustic liquid. Forms explosive compounds with many heavy metals such as Ag, Pb, Zn and their salts, especially halide salts.
Sodium and potassium hydroxides
Extremely caustic. Can cause severe burns. Protect skin and eyes when working with these alkalis as solids or concentrated solutions. Add pellets to H O, not vice versa.
Flammable solvents
Do not let vapours concentrate to flammable level in work area. It is nearly impossible to eliminate all chance of sparks from static electricity even if electric equipment is grounded. Use effective fume removal device to remove these vapours when released.
Toxic solvents
Vapours from some volatile solvents are highly toxic. Several of these solvents are readily absorbed through skin. Use effective fume removal device to remove vapours of these solvents as they are liberated.
