Study Set Content:
for crude drugs; require a distinct type of technique
Miscellaneous/ Special Methods
- Ash content
- Acid value
- Water content
Miscellaneous/ Special Methods
- analytical methods which the volume of a solution of a known concentration consumed during the analysis is taken as a measure of amount of active constituent in a sample being analyzed
Titrimetric Method
Apparatuses used for volumetric analysis
- analytical balance
- beaker
- flask
- funnels
Two Types of Volumetric Apparatus
- made to deliver a definite volume of liquid.
- burette
- pipette
- made to contain a definite volume of liquid.
- volumetric flask
- graduated cylinder
Temperature specified by USP & NF for volumetric measurements is
25℃.
The National Bureau of Standard adopted
20℃.
graduated glass tubes of uniform bore throughout the whole length
Burettes
How to read burettes
Readings should always be made at the lowest point of the meniscus
- the surface of liquids in narrow tubes that is always curved due to capillarity.
- the curve seen at the top of a liquid in response to its container
- can either be concave or convex
Meniscus
Meniscus how to read
Read on eye level.
Concave - e.g.
water
Convex - e.g
mercury
- are calibrated to contain the indicated volume at 25ᵒC.
- make up standard solution to a given volume
Volumetric flasks
How to read volumetric flasks
- They are graduated to contain and
not to deliver the calibrated volume.
- used to channel liquid or fine-grained
substances into containers with small openings
Funnel
- a piece of soft rubber tubing fitted to the end of a glass rod
- used to loosen from the walls of the containing vessel
adhering particles that are not removable by a stream of
water from a wash bottle
Policeman
- made of high grade porcelain.
- They withstand high temperatures and are
- suitable for the use of ignition of most drugs and precipitates
Crucibles
- designed for separation of precipitates by suction filtration.
- it has a perforated bottom upon which is bedded as a
mat of asbestos, thus making it possible to collect,
wash dry and weigh a precipitate in the same crucible.
Gooch Filtration Cubicle
- have fused in sintered or fritted glass bottoms
and have various porosities such as medium and fine.
Fritted-Glass Crucible
