Crucible, Porcelain, Gooch

Quick Answer: A porcelain Gooch crucible is a glazed porcelain crucible with a perforated base, which holds a filter mat or disc so that a precipitate can be filtered under suction, then dried or ignited and weighed in the same vessel for gravimetric analysis.

Filter and Crucible in One

In gravimetric analysis a precipitate is collected, dried or ignited, and weighed. Filtering through paper and then transferring the solid to a crucible risks losing some of it. The Gooch crucible avoids the transfer: its base is pierced with small holes, and a filter layer laid over them retains the precipitate while the liquid is drawn through. The crucible, with the precipitate inside, then goes straight into an oven or furnace.

The filter layer was once an asbestos mat; today glass-fibre filter circles cut to fit the base are used instead, sometimes held flat by a perforated disc. The crucible is set in a rubber adapter on a filter tube for Gooch crucible or a funnel in a filtering flask, and suction is applied. Porcelain allows ignition at higher temperatures than a sintered glass crucible, which is its main advantage for precipitates that must be ignited.

Size is not given in the listing, so match the crucible to your adapter. The filter discs in this range can sit in the base as a support for the fibre layer.

Technique and Care

• Prepare the filter layer carefully so no gaps are left at the edges.
• Wash the precipitate with small portions of wash liquid, letting each drain before adding the next.
• Bring the empty crucible with its mat to constant mass before use.
• After use, remove the mat and clear the perforations with water or a suitable dilute acid.

Specifications

Applications

• Gravimetric determinations where the precipitate is ignited before weighing.
• Collecting and weighing insoluble residues, such as acid-insoluble ash.
• Filtering hot or strongly acidic mixtures that would weaken paper.
• Teaching the classical Gooch technique in analytical chemistry courses.

Why Choose LabEquip

Analytical chemistry labs, cement and mineral testing labs and colleges teaching gravimetry buy Gooch crucibles with their adapters. LabEquip lists this porcelain version in General Lab Products; ask about sizes via the contact page.

Frequently Asked Questions

What is a Gooch crucible?

It is a crucible with a perforated base that acts as a filter support. A filter mat laid over the holes retains a precipitate under suction, and the crucible then goes into an oven or furnace for drying and weighing.

What filter material is used in a porcelain Gooch crucible?

Glass-fibre filter circles cut to the base diameter are common today, sometimes with a perforated porcelain disc. Asbestos mats were used historically but have been abandoned because of the health risks.

How is a Gooch crucible fitted to a filtering flask?

It sits in a rubber collar or adapter in the top of a filter tube or funnel, which passes through a bung into the filtering flask. Suction from a pump draws the liquid through the perforations.

Porcelain or sintered glass: which Gooch crucible should I choose?

Porcelain tolerates higher ignition temperatures, so it suits precipitates that must be ignited. Sintered glass needs no separate mat and is convenient for precipitates that are only dried at moderate temperatures.

Why should the empty crucible be ignited before use?

Heating the crucible with its mat, cooling it in a desiccator and weighing until constant gives the true empty mass. Without this, moisture or loose fibres would be counted as precipitate.

How is the crucible cleaned after an analysis?

Remove the used mat, rinse out the precipitate, and dissolve any residue with a suitable dilute acid. Rinse through the holes from below with water, then dry.

Last Updated: September 2026