GLASSWARES

Geromil J. Lara, RMT, MSMT

GENERAL CATEGORIES OF GLASSBOROSILICATE GLASS Melts at temperature between 750 and 1,100 degrees Celsius

Hard, free of heavy metals Resistant to thermal shock and alkaline corrosion

GENERAL CATEGORIES OF GLASSBOROSILICATE GLASS

Used for situations involving sudden changes in temperature, an open flame, or electric heating elements

GENERAL CATEGORIES OF GLASSBOROSILICATE GLASS

Should not be heated above its strain point Pyrex® Corex® Kimax® Vycor®

GENERAL CATEGORIES OF GLASSBOROSILICATE

GLASS Pyrex®

Strain point of 515 degrees Celsius

GENERAL CATEGORIES OF GLASSBOROSILICATE GLASS Corex®

High-impact, extremely strong glass often used in the manufacture of centrifuge tubes

With aluminosilicate

GENERAL CATEGORIES OF GLASSBOROSILICATE GLASS Vycor®

Recommended for use in application involving high temperature, drastic heat shock, and extreme chemical

GENERAL CATEGORIES OF GLASSBOROSILICATE GLASS Vycor®

Used primarily in ashing and ignition techniques

GENERAL CATEGORIES OF GLASSBOROSILICATE GLASS Vycor®

Can be heated to 900 degrees Celsius and can withstand downshocks from this temperature to ice water

GENERAL CATEGORIES OF GLASSSODA-LIME GLASS Sometimes referred to as flint glass

Has a high coefficient of expansion

Readily attacked by alkaline solutions

GENERAL CATEGORIES OF GLASSSODA-LIME GLASS Commonly used for making volumetric flasks, stirring rods, and single-use pipets or tubes

Minerals can be leached from the glass into the stored solutions

GENERAL CATEGORIES OF GLASSLOW ACTINIC

GLASS Used to reduce light exposure to its content

Amber-colored glass

GENERAL CATEGORIES OF GLASSHIGH SILICA GLASS Similar to quartz

Accurate spectrophotometer cuvettes

MEASURING VESSELS

GRADUATED CYLINDERS Semi-accurate Extremely convenient for rapid measurement of liquid volumes

Should never be heated

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BURETS Can deliver any volume up to its maximum capacity

Used for titration Extremely accurate in dispensing aliquots of a solution

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VOLUMETRIC FLASK Designed to prepare solutions of precisely known concentrations

Standard solutions

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PIPETS Used to transfer measured volumes of liquid between containers Design Drainage characteristics Type

MEASURING VESSELS

PIPETS Design

To Contain (TC) holds or contains a particular volume but does not dispense that exact volume

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PIPETS Design

To Deliver (TD) made by weighing the necessary volume of water which when allowed to flow by gravity will deliver the exact volume

MEASURING VESSELS

PIPETS Drainage Characteristics

To Deliver (TD) Those with a single painted or frosted ring at the top should be allowed to simply drain with the tip placed against the side of the receiving vessel

self-draining

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PIPETS Drainage

Characteristics To Deliver (TD)

Those with double rings are designed to be "blown out" by pushing a small amount of air out of the pipet, completely emptying it

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PIPETS Mohr pipet

Does not have graduations to the tip

self-draining pipet, but the tip should not be allowed to touch the vessel while the pipet is draining

MEASURING VESSELS

PIPETS Serologic pipet

Has graduation marks to the tip, and is generally a blowout pipet

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PIPETS Micropipet

With a total holding volume of less than 1 mL

It may be designed as either a Mohr or serologic pipet

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PIPETS Transfer pipet

Designed to dispense one volume without further subdivisionsOstwald-Folin PipetPasteur Pipet

MEASURING VESSELS

PIPETS Automatic and Semi-

automatic pipet Commonly used in

the clinical laboratory