Page 123 - The Veterinary Laboratory and Field Manual 3rd Edition

92 Willy Schauwers

Table 2.4 Plastic ware properties: chemical resistance and possibility to autoclave.

Plastic ware Chemical resistance Autoclavable
Polypropylene (PP) Good Yes
Low-density polyethylene (LDPE) Good No
High-density polyethylene (HDPE) Good No
Polymethylpentene (PMP, TPX) Good Yes
Polycarbonate (PC) Moderate Yes
Polytetrafluoroethylene (PTFE) Very good Yes
Polymethylmethacrylate (PMMA) Moderate No
Polystyrene (PS) Moderate No
Polyvinylchloride (PVC) Moderate No

volumetric accuracy The following information may also be added:

Volumetric glassware is manufactured and cali- • country of origin
brated in accordance with international ISO • error limit
standards to permit very accurate determina- • standard: the standard to which the product
tion and measurement of specific volumes. All conforms
of the volumetric glassware is marked with a set • certified glassware bears a serial number/
of inscriptions in accordance with any specific batch number for identification and trace-
standard associated with it. ability.
Mandatory inscriptions include:
General guidelines for use include the following.
• manufacturer
• class: • Ensure that all volumetric glassware is kept

scrupulously clean. Dirt, and especially
• class A/AS – highest level of accuracy (S
stands for swift delivery of pipettes and grease, can distort the shape of the meniscus
burettes), glass or plastic and also cause droplets of liquid to adhere to
• class B – general purpose work calibrated the vessel walls. Both seriously impair accu-
to a lower level of accuracy, glass or plastic racy (good cleanliness is indicated by uniform
wetting of the glass surface with distilled
• nominal volume water).
• volume unit • Never pipette by mouth. Always use a pur-
• calibration temperature pose designed pipette filler.
• for pipettes: • Autoclaving at 121°C and cleaning in auto-
matic dishwashers is acceptable and will not
• IN: calibrated to contain, or affect the accuracy of glassware.
• EX: calibrated to deliver • All items should be held in a vertical position
• waiting time when reading the meniscus. The menis-
• blowout: indication that last drop should cus should be at eye level to avoid parallax
be blown out of jet. errors.

Vet Lab.indb 92 26/03/2019 10:25