What do the tolerance limits on pipettes mean?
These tolerance limits reflect what is reasonably achievable in a working laboratory. They presume that the pipette is calibrated and functioning properly, is used with good quality tips, and is tested by a reasonably skilled operator.
What is the capacity of a Class A transfer volumetric Pipet?
For example, a 25 mL Class A Transfer Volumetric Pipet has a capacity tolerance of ± 0.03 mL, and a 50 mL Class A Buret has a tolerance of ±0.05 mL at full capacity. What is a Class A pipette? Class A, USP, Certified Glass Bulb Pipettes Class A, USP, certified single-volume bulb pipette.
What are the limits of a variable volume pipette?
These limits are based on a simple guideline: Two percent of full scale at all volume settings. 5 For example, the systematic error for a 100 μL variable-volume pipette is ±2.0 μL (2%) at the 100 μL setting, and ±2.0 μL (4%) at the 50 μL setting.
What is a Class A Pipet?
Glass Class A pipets unserialized and calibrated “To Deliver”. Designed to ASTM E969 specification for accuracy and ASTM E1273 for color coding. A 12% surcharge may be added to the product price.
What is the tolerance of a volumetric pipette?
ASTM standard E969 defines the standard tolerance for volumetric transfer pipettes. The tolerance depends on the size: a 0.5-mL pipette has a tolerance of ±0.006 mL, while a 50-mL pipette has a tolerance of ±0.05 mL.
What is the precision of a 10 mL volumetric pipette?
volume 10 mL, accuracy: 0.02 mL.
What are the tolerances for Class A volumetric glassware?
Even Class A volumetric glassware is not absolute but rather has a tolerance from its stated nominal value. For example, a 25 mL Class A Transfer Volumetric Pipet has a capacity tolerance of ± 0.03 mL, and a 50 mL Class A Buret has a tolerance of ±0.05 mL at full capacity.
What is the accuracy of the 10 mL graduated pipet?
A standardized graduated pipette (Class A or AS) with a nominal capacity of 10 ml and an overall length of about 360 mm has a maximum permissible error of ±0.05 ml.
What is the uncertainty of a 10mL pipette?
To find the uncertainties and approximate number of significant figures when using volumetric glassware use Table 1. Table 1. Capacity Tolerances for Class A Volumetric Glassware. A 10-ml pipet is listed as 10.00 0.02, which is close enough to 4 significant figures, 10.00 ml.
What is the uncertainty of a 10 mL volumetric flask?
±0.02Uncertainties for Volumetric GlasswareItemVolume (mL)Uncertainty (mL)Volumetric flask100.00±0.0850.00±0.0525.00±0.0310.00±0.0214 more rows•Jun 12, 2008
What is the tolerance of a 10 mL graduated cylinder?
±0.10ml10ml graduated measuring cylinder made of high quality, heavy duty Borosilicate 3.3 glass. Spout for easy pouring, and hexagonal base for extra stability. Class A tolerance, ±0.10ml as per DIN EN ISO 4788 standard.
What is the uncertainty of a 10 mL graduated cylinder?
0.1mLEven when using expensive lab equipment there some degree of uncertainty in measurement. The general rule of thumb is: you can estimate one more digit past the smallest division on the measuring device. If you look at a 10mL graduated cylinder, for example, the smallest graduation is tenth of a milliliter (0.1mL).
What is the manufacturing tolerance of a class A 5 mL volumetric pipet?
5ml capacity volumetric flask made of high quality, heavy duty 3.3 borosilicate glass. Conforms to ASTM E288 standards. Class A, tolerance ±0.020 ml.
What is the uncertainty of a graduated pipette?
All graduated glassware is read with one estimated digit, so this measurement is recorded correctly to the nearest 0.1 mL, with an understood uncertainty of ± 0.1 mL.
Why is a 10 mL graduated cylinder more precise?
The accuracy of a graduated cylinder is higher because the graduations on the cylinder make it easier to more precisely fill, pour, measure, and read the amount of liquid contained within.
What are Class A pipettes?
Class A pipets are manufactured to provide high accuracy and they are required to meet the requirements and tolerances in ASTM E969 − 02 (Reapproved 2012) “Standard Specification for Glass Volumetric (Transfer) Pipets.”
What happens if a pipette is too strict?
Tolerances that are too strict can cause a large number of so-called “false failures,” where a pipette in good working order produces test results that are out of tolerance. Tolerances that are too broad can degrade the quality of the laboratory’s analytical work.
What factors affect pipette performance?
Pipette performance is influenced significantly by environmental factors such as temperature and humidity. 1 This means that a pipette calibrated at an environmentally controlled facility may deliver incorrectly on the benchtop. 2 Artel therefore recommends testing pipette performance under working conditions.
What tip to use for pipette?
If the user chooses another type of tip (e.g., a filter, elongated or gel loading tip), or a lower quality tip, the pipette can easily test outside of the manufacturer’s tolerances.
What is the NIST number for volumetric glassware?
All approved volumetric glassware used is certified to comply with the Class A tolerance requirements of ASTM Standard E 288 and to Federal specifications in NIST Circular Number 434.
What temperature is volumetric glassware calibrated at?
In addition, volumetric glassware is calibrated at a specific temperature, usually 20°C, but quite often it is used to deliver or contain volumes at a different temperature.
