Plastic Burettes

Class A burettes are calibrated to tight tolerances and are suitable for analytical and university work requiring accurate, repeatable titration volumes. Class B burettes are less precise and are the standard choice for school teaching labs where approximate accuracy is acceptable. Both are available in 25 ml, 50 ml and 100 ml sizes.

PTFE (polytetrafluoroethylene) stopcocks are chemically inert, require no grease, and resist all common titrants including permanganate and silver nitrate. PP stopcocks are adequate for general aqueous titrations but may swell slightly with some organic solvents. Avoid glass stopcock burettes with strongly alkaline titrants.

The 50 ml burette is the standard size for most quantitative analysis and school titrations, allowing readings to 0.05 ml. The 25 ml burette suits micro-scale titrations where reagent volumes are limited, while the 100 ml size gives more room for larger-scale work or repeat measurements without refilling as often. All three share the same 0.1 ml graduation interval.

A plastic burette needs a matching clamp and retort stand to hold it vertical during titration. Check that the burette clamp jaw opens wide enough for the burette diameter and that the stand is stable enough to prevent tipping. SmartLabs stocks PP burette clamps sized for both 25 ml and 50 ml burettes.

Most aqueous titrants are compatible with acrylic or PP burettes, including hydrochloric acid, sodium hydroxide, potassium permanganate, iodine, and EDTA. Concentrated organic solvents such as acetone, chloroform, and ethyl acetate will attack acrylic (PMMA) burettes and should be used in glass only. Always check the chemical compatibility of the specific plastic before using an unfamiliar titrant.

Class A burettes meet the tightest tolerance standard and are certified for analytical work. A 50 ml Class A burette has a tolerance of plus or minus 0.05 ml. Class B burettes have tolerances roughly twice as wide and are suitable for teaching purposes where the exact volume is less critical. For university-level quantitative analysis, always specify Class A.

PTFE stopcocks require no grease and should never be lubricated with stopcock grease, which causes the bore to clog. After use, rinse the burette with water, drain it fully, and store it inverted or with the stopcock removed to prevent the bore sticking. If the stopcock leaks, check for debris in the bore or worn PTFE seals and replace if necessary.

Class A acrylic burettes with PTFE stopcocks are accurate enough for most undergraduate quantitative analysis work. The graduation tolerance of plus or minus 0.05 ml per 50 ml meets the requirements of most university practical manuals. For research-grade primary standard preparations, borosilicate glass Class A burettes with certified tolerances are still the preferred option.

Our acrylic burette comes in 25 ml, 50 ml and 100 ml, all fitted with a PTFE stopcock. The 25 ml size suits small-scale school titrations, 50 ml covers most standard practicals, and 100 ml gives you more room for larger-scale work without refilling as often.