ASTM E672-87(1996)e1

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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e1
Designation: E 672 – 87 (Reapproved 1996)
Standard Specification for
Disposable Glass Micropipets
This standard is issued under the fixed designation E 672; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Editorial changes were made throughout in July 1996.
1. Scope 4. Classification
1.1 This specification covers two different types of dispos- 4.1 This specification covers two different pipet designs as
able micropipets, calibrated “to contain,” used in measuring follows:
microlitre volumes of liquids. 4.1.1 Type I—Disposable micropipets with calibration line
1.2 The values stated in SI units are to be regarded as the and color coding (see Fig. 1 and Table 1).
standard. 4.1.2 Type II—Disposable micropipets void of markings
1.3 The following precautionary caveat pertains only to (see Fig. 2 and Table 2).
paragraph 9.1.1 of this specification. This standard does not
NOTE 2—Type I pipets were originally specified by the Department of
purport to address all of the safety concerns, if any, associated
Defense under MIL-P-36722.
with its use. It is the responsibility of the user of this standard
to establish appropriate safety and health practices and 5. Materials and Manufacture
determine the applicability of regulatory limitations prior to
5.1 The pipets made to these specifications shall be fabri-
use.
cated from borosilicate glass, Type I, Class A or B or soda lime
glass, Type II, in accordance with Specification E 438.
2. Referenced Documents
2.1 ASTM Standards: 6. Dimensions and Permissible Variations
E 438 Specification for Glasses in Laboratory Apparatus
6.1 Design—Pipets shall be of one piece construction in
2.2 ISO Standard:
accordance with Table 1 and Table 2 for shape, dimensions,
R 1769 Color Coding for Pipets
and permissible variations. Any cross-section of the pipet,
taken in a plane perpendicular to the longitudinal axis, shall be
3. Terminology
circular.
3.1 Definitions of Terms Specific to This Standard:
6.2 Capacity—The pipet capacity shall be stated on the
3.1.1 accuracy—the closeness of agreement between the
package label, expressed as μL (microlitre); this shall be known
nominal value and the mean volume, obtained by applying the
as the stated capacity, V , in making subsequent calculations.
test procedure specified in 9.4.1. It is quantified by the
The expected deviation from the stated capacity shall be
inaccuracy of the mean (bias).
expressed as accuracy and coefficient of variation and shall be
3.1.2 disposable micropipet—such micropipets will only be
tested for capacity as specified in 9.1. The unit, microlitre, μL,
expected to provide their specified performance during their
may be considered as equivalent to .001 cm .
original use or operation.
6.2.1 Accuracy (see 4.1)—The accuracy shall be determined
as specified in 9.4 and shall be within the limits given in Table
NOTE 1—The descriptions of “accuracy” and “repeatability” apply only
in cases where the distributions are Gaussian. 1 and Table 2.
6.2.2 Coeffıcient of Variation (see section 4.2)—The coeffi-
3.1.3 repeatability—the closeness of agreement between the
cient of variation shall be determined as specified in 9.4 and
individual volumes obtained by applying the test procedure
shall be within the limits given in Table 1 and Table 2.
specified in 9.4.2. It is quantified by the imprecision.
6.3 Capacity Mark—Pipets in Fig. 1 shall have a capacity
line that is calibrated “to contain” a volume of liquid at 20°C.
The capacity line shall be 0.3 to 0.5 mm wide and shall
This specification is under the jurisdiction of ASTM Committee E-41 on
Laboratory Apparatus and is the direct responsibility of Subcommittee E 41.01on
completely encircle the pipet in a plane perpendicular to its
Glass Apparatus.
longitudinal axis.
Current edition approved March 27, 1987. Published May 1987. Originally
6.4 Identification Markings:
published as E 672 – 78. Last previous edition E 672 – 85.
Annual Book of ASTM Standards, Vol 14.02. 6.4.1 Type I—The pipets in Fig. 1 shall be identified for
Available from American National Standards Institute, 11 W. 42nd St., 13th
capacity by a color code marking on each pipet consisting of
Floor, New York, NY 10036.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
E 672
FIG. 1 Type I Pipet
TABLE 1 Dimensions for Type I Pipet
Maximum Volumetric Deviation
Stated Capacity, Minimum Di- Minimum Wall
Color Code
Coefficient of
μL ameter A, mm B, mm
Accuracy, %
Variation, %
5 white 1.0 0.35 61.0 <1.5
10 orange 1.0 0.25 60.5 <1.0
20 black 1.1 0.25 60.5 <1.0
25 2 white 1.1 0.25 60.5 <1.0
50 green 1.3 0.20 60.5 <1.0
100 blue 1.6 0.20 60.5 <1.0
200 red 2.2 0.20 60.5 <1.0
FIG. 2 Type II Pipet
one or two color bands (see Table 1). For a code consisting of 7. Workmanship, Finish, and Appearance
one band, the band shall be from 2 to 6 mm wide; for a code
7.1 The pipets in Fig. 1 and Fig. 2 shall be free of defects
consisting of two bands, each band shall be 2 to 6 mm wide and
that will detract from their appearance or may impair their
separated with a space of 2 to 6 mm. The color code band, or
serviceability. The pipets shall be free of significant foreign
bands, shall completely encircle the pipet in a plane perpen-
matter, loose or embedded lint or chips that affect the bore, or
dicular to its longitudinal axis. The location of color band, or
stains when viewed under normal room lighting.
bands, shall be as specified in Fig. 1 with the selection of color,
7.2 The calibration line and color code on Type I pipets shall
to designate capacity, according to ISO Recommendation
be applied to the glass pipet at locations specified in Fig. 1. The
R-1769.
6.4.2 Type II—Pipets in Fig. 2 are devoid of any markings calibration line shall be sufficiently deposited on the glass to
and shall be identified for capacity on the package label. enable the setting of a meniscus and the color band shall be
E 672
TABLE 2 Dimensions for Type II Pipet
Maximum Volumetric Deviation
Stated Capacity, Minimum Minimum Di- Minimum Wall
Coefficient of
μL Length A, mm ameter B, mm C, mm
Accuracy, %
Variation, %
1 20 0.5 0.20 61.5 <2.0
2 20 0.5 0.20 61.2 <1.5
3 20 0.6 0.20 61.2 <1.5
4 20 0.6 0.20 61.2 <1.5
5 20 0.6 0.20 61.2 <1.5
10 20 0.6 0.10 61.0 <1.2
20 20 0.6 0.10 61.0 <1.2
25 30 0.6 0.10 61.0 <1.2
50 30 1.0 0.10 61.0 <1.2
100 50 1.3 0.10 61.0 <1.2
sufficiently deposited on the glass to identify the pipet as to its 8.2.1.2 Method B—The position of the highest point of the
stated volume. meniscus with reference to the graduation line is such that it is
in the plane of the middle of the graduation line. This position
8. Reading and Setting the Meniscus
of the meniscus is obtained by making the setting in the center
8.1 Reading a Liquid Meniscus (Type I only)—For all
of the ellipse formed by the graduation line on the front and the
pipets, the reading is made on the lowest point of the meniscus.
back of the tube as observed by having the eye slightly above
In order that the lowest point may be observed, it is necessary
the plane of the graduation line. The setting is accurate if, as
to place a shade of some dark material immediately below and
the eye is lowered and the ellipse narrows, the highest point of
behind the meniscus, which renders the profile of the meniscus
the meniscus remains midway between the front and rear
dark and clearly visible against a light background.
portions of the graduation line. By this method it is possible to
8.1.1 Setting a Liquid Meniscus—Setting of the meniscus
observe the approach of the meniscus from either above or
shall be performed by one of the following methods. Wherever
below the line to its proper setting.
practical, the meniscus should descend to the position of
NOTE 3—The difference bet
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