filtration simple crucible gooch filter crucible : fritted glass(= sintered glass) funnel porosity :...
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Filtration
Simple crucible
Gooch filter crucible : fritted glass(= sintered glass) funnel
porosity : f (=fine), m (=medium), c (=coarse)
Aspirator or vacuum pump
Trap
Mother liquor
Filtrate
Decantation is the process of pouring a liquid gently so as to not disturb a solid in the bottom of the container.
Rubber policeman
Squirt bottle
Gooch crucible
Filtering crucible
Separating funnel
Crucibles
Train for vacuum filtration
Vacuum filtration with a Gooch crucible that has a porous (fritted) glass disk through which liquid can pass. Suction can be applied by the vacuum system or by an aspirator that uses flowing water to create vacuum. The trap prevents backup of tap water from the aspirator into the suction flask. Alternatively, the trap prevents liquid in your suction flask from being accidentally sucked into the vacuum system.
Ashless filter-paper :
Specially treated filter-paper (pulps treated by using 6M HCl, HF) that leaves a negligible residue(=incombustible matter) after ignition. Ash 0.2mg when a filter-paper(I.D. 11cm) has been incinerated.
(Left) Filtering a precipitate. The conical funnel is supported by a metal or wood ring attached to a ring stand. (Center) Washing by decantation. (Right) Transferring the precipitate.
Creeping is a process in which a solid moves up the side of a wetted container or filter paper.
Folding filter paper for a conical funnel.
(a) Fold the paper in half.
(b) Then fold it in half again.
(c) Tear off a corner to allow better seating of the paper in the funnel.
(d) Open the side that was not torn when fitting the paper in the funnel.
Method for folding and seating a filter paper
The filtering operation.
Washing by decantation and transferring the precipitate
Ignition of precipitate
Pipets and sylinder.
Pipets and syringes
TC 20oC = calibrated to contain the indicated volume at 20oC (ambient temperature)
E : eingu
TD 20oC = calibrated to deliver the indicated volume at 20oC
A : ausgu
The coefficient of expansion for dilute aqueous solution: 0.025%/oC
VT1 = VT2 + 0.00025(T1-T2)VT2
where T1 > T2
Transfer pipet
Don’t blow out the last drop
Measuring (Mohr) pipet
Microliter pipet (Eppendorf)
Examples of pipets
a. Volumetric (TD)
b. Mohr : Measuring (TD)
c. Serological : Measuring (TD)
d. Eppendorf micropipet (TD)
e. Ostwald-Folin (TD)
f. Lambda (TC)
Pipet fillers and pipets
1. Latex bulb
2. Pipet filler
3. Mechanical pipet filler
4. Pipettor pump
5. Pasteur pipet
6. Volumetric pipet
7. Mohr pipet
8. Serological pipet
Safety rubber bulb filler and auto-filler
Safety rubber bulb filler
A : press on valve A and squeeze bulb
S : Insert pipet into liquid sample. Press on valve S. Suction draws liquid to desired level.
E : Press on valve E to expel liquid sample.
To deliver the last drop, maintain pressure on valve E, cover E inlet with middle finger, and squeeze the small bulb.
E
A
S
1 2 3 4
Transfer pipet.
Measuring (Mohr) pipet.
Microliter pipet with disposable plastic tip.
Volume selection dial of microliter pipet.
Repeater pipet, which can deliver preset volumes between 10 L and 5 mL to 48 times at 1-s intervals without refilling.
Hamilton syringe
Digital dispenser for syringes with volumes of 0.5 to 500 microliter provides accuracy and precision of 0.5%
Micropipet (lambda pipet) : 1 l ( 10–6 l)
Eppendorf
Disposable plastic(polypropylene) tip
Hamilton syringe
needle(gauge no)
barrel
plunger
Syringe pump
Loop injector : Rheodyne injectorHamilton syringe
Rheodyne loop injector.
Syringe pump