1、Designation: E 672 87 (Reapproved 2006)Standard Specification forDisposable Glass Micropipets1This standard is issued under the fixed designation E 672; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A n
2、umber in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This specification covers two different types of dispo
3、s-able micropipets, calibrated “to contain,” used in measuringmicrolitre volumes of liquids.1.2 The values stated in SI units are to be regarded as thestandard.1.3 The following precautionary caveat pertains only toparagraph 9.1.1 of this specification. This standard does notpurport to address all o
4、f the safety concerns, if any, associatedwith its use. It is the responsibility of the user of this standardto establish appropriate safety and health practices anddetermine the applicability of regulatory limitations prior touse.2. Referenced Documents2.1 ASTM Standards:2E 438 Specification for Gla
5、sses in Laboratory Apparatus2.2 ISO Standard:3R 1769 Color Coding for Pipets3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 accuracythe closeness of agreement between thenominal value and the mean volume, obtained by applying thetest procedure specified in 9.4.1. It is quantif
6、ied by theinaccuracy of the mean (bias).3.1.2 disposable micropipetsuch micropipets will only beexpected to provide their specified performance during theiroriginal use or operation.NOTE 1The descriptions of “accuracy” and “repeatability” apply onlyin cases where the distributions are Gaussian.3.1.3
7、 repeatabilitythe closeness of agreement between theindividual volumes obtained by applying the test procedurespecified in 9.4.2. It is quantified by the imprecision.4. Classification4.1 This specification covers two different pipet designs asfollows:4.1.1 Type IDisposable micropipets with calibrati
8、on lineand color coding (see Fig. 1 and Table 1).4.1.2 Type IIDisposable micropipets void of markings(see Fig. 2 and Table 2).NOTE 2Type I pipets were originally specified by the Department ofDefense under MIL-P-36722.5. Materials and Manufacture5.1 The pipets made to these specifications shall be f
9、abri-cated from borosilicate glass, Type I, Class A or B or soda limeglass, Type II, in accordance with Specification E 438.6. Dimensions and Permissible Variations6.1 DesignPipets shall be of one piece construction inaccordance with Table 1 and Table 2 for shape, dimensions,and permissible variatio
10、ns. Any cross-section of the pipet,taken in a plane perpendicular to the longitudinal axis, shall becircular.6.2 CapacityThe pipet capacity shall be stated on thepackage label, expressed as L(microlitre); this shall be knownas the stated capacity, V1, in making subsequent calculations.The expected d
11、eviation from the stated capacity shall beexpressed as accuracy and coefficient of variation and shall betested for capacity as specified in 9.1. The unit, microlitre, L,may be considered as equivalent to 0.001 cm3.6.2.1 Accuracy (see 4.1)The accuracy shall be determinedas specified in 9.4 and shall
12、 be within the limits given in Table1 and Table 2.6.2.2 Coeffcient of Variation (see section 4.2)The coeffi-cient of variation shall be determined as specified in 9.4 andshall be within the limits given in Table 1 and Table 2.1This specification is under the jurisdiction of ASTM Committee E41 onLabo
13、ratory Apparatus and is the direct responsibility of Subcommittee E41.01 onApparatus.Current edition approved Nov. 1, 2006. Published December 2006. Originallyapproved in 1978. Last previous edition approved in 2001 as E 672 87 (2001)e1.2For referenced ASTM standards, visit the ASTM website, www.ast
14、m.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.o
15、rg.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.3 Capacity MarkPipets in Fig. 1 shall have a capacityline that is calibrated “to contain” a volume of liquid at 20C.The capacity line shall be 0.3 to 0.5 mm wide and shallcompletel
16、y encircle the pipet in a plane perpendicular to itslongitudinal axis.6.4 Identification Markings:6.4.1 Type IThe pipets in Fig. 1 shall be identified forcapacity by a color code marking on each pipet consisting ofone or two color bands (see Table 1). For a code consisting ofone band, the band shall
17、 be from 2 to 6 mm wide; for a codeconsisting of two bands, each band shall be 2 to 6 mm wide andseparated with a space of 2 to 6 mm. The color code band, orbands, shall completely encircle the pipet in a plane perpen-dicular to its longitudinal axis. The location of color band, orbands, shall be as
18、 specified in Fig. 1 with the selection of color,to designate capacity, according to ISO RecommendationR-1769.6.4.2 Type IIPipets in Fig. 2 are devoid of any markingsand shall be identified for capacity on the package label.7. Workmanship, Finish, and Appearance7.1 The pipets in Fig. 1 and Fig. 2 sh
19、all be free of defectsthat will detract from their appearance or may impair theirserviceability. The pipets shall be free of significant foreignFIG. 1 Type I PipetTABLE 1 Dimensions for Type I PipetStated Capacity,LColor CodeMinimum Di-ameter A, mmMinimum WallB, mmMaximum Volumetric DeviationAccurac
20、y, %Coefficient ofVariation, %5 white 1.0 0.35 61.0 1.510 orange 1.0 0.25 60.5 1.020 black 1.1 0.25 60.5 1.025 2 white 1.1 0.25 60.5 1.050 green 1.3 0.20 60.5 1.0100 blue 1.6 0.20 60.5 1.0200 red 2.2 0.20 60.5 1.0FIG.2TypeIIPipetE 672 87 (2006)2matter, loose or embedded lint or chips that affect the
21、 bore, orstains when viewed under normal room lighting.7.2 The calibration line and color code on Type I pipets shallbe applied to the glass pipet at locations specified in Fig. 1. Thecalibration line shall be sufficiently deposited on the glass toenable the setting of a meniscus and the color band
22、shall besufficiently deposited on the glass to identify the pipet as to itsstated volume.8. Reading and Setting the Meniscus8.1 Reading a Liquid Meniscus (Type I only)For allpipets, the reading is made on the lowest point of the meniscus.In order that the lowest point may be observed, it is necessar
23、yto place a shade of some dark material immediately below andbehind the meniscus, which renders the profile of the meniscusdark and clearly visible against a light background.8.1.1 Setting a Liquid MeniscusSetting of the meniscusshall be performed by one of the following methods. Whereverpractical,
24、the meniscus should descend to the position ofsetting.8.1.1.1 Method AThe position of the lowest point of themeniscus with reference to the graduation line is horizontallytangent to the plane of the upper edge of the graduation line.The position of the meniscus is obtained by having the eye inthe sa
25、me plane of the upper edge of the graduation line.8.1.1.2 Method BThe position of the lowest point of themeniscus with reference to the graduation line is such that it isin the plane of the middle of the graduation line. This positionof the meniscus is obtained by making the setting in the centerof
26、the ellipse formed by the graduation line on the front and theback of the tube as observed by having the eye slightly belowthe plane of the graduation line. The setting is accurate if, asthe eye is raised and the ellipse narrows, the lowest point of themeniscus remains midway between the front and r
27、ear portionsof the graduation line. By this method it is possible to observethe approach of the meniscus from either above or below theline to its proper setting.8.2 Reading a Mercury Meniscus (Type I only)For allpipets, the reading is made at the highest point of the meniscus.In order that the high
28、est point may be observed, it is necessaryto place a shade of some light material immediately above andbehind the meniscus, which renders the profile of the meniscusdark and clearly visible against a light background.8.2.1 Setting a Mercury MeniscusSetting of the meniscusshall be performed by one of
29、 the following methods. Whereverpractical, the meniscus should descend to the position ofsetting.8.2.1.1 Method AThe position of the highest point of themeniscus with reference to the graduation line is horizontallytangent to the plane of the lower edge of the graduation line.The position of the men
30、iscus is obtained by having the eye inthe same plane of the lower edge of the graduation line.8.2.1.2 Method BThe position of the highest point of themeniscus with reference to the graduation line is such that it isin the plane of the middle of the graduation line. This positionof the meniscus is ob
31、tained by making the setting in the centerof the ellipse formed by the graduation line on the front and theback of the tube as observed by having the eye slightly abovethe plane of the graduation line. The setting is accurate if, asthe eye is lowered and the ellipse narrows, the highest point ofthe
32、meniscus remains midway between the front and rearportions of the graduation line. By this method it is possible toobserve the approach of the meniscus from either above orbelow the line to its proper setting.NOTE 3The difference between meniscus positions resulting from thealternative methods of ad
33、justment is the volume equivalent of one half thethickness of the graduation line. When working to the highest attainableaccuracy, the difference between the two methods of adjustment isunlikely to exceed 0.4 % volumetric error from stated capacity and acorrection can be calculated where necessary.9
34、. Testing9.1 Capacity (Single Pipet):9.1.1 Type I (Using Mercury)Allow a dry pipet and acontainer of triple distilled mercury to stand at room tempera-ture of 20 to 25C for 2 h. Fill the pipet with mercury andadjust to the calibration line in accordance with 8.2 and 8.2.1.Discharge the mercury in th
35、e pipet into a clean tared dish, andreweigh the dish, together with the mercury content. Recordthe room temperature. From the recorded weight of themercury discharged into the dish and the recorded temperature,calculate the volume of mercury (representing the observedcapacity of the pipet) in accord
36、ance with 9.2 and Table X1.9.1.2 Type I (Using Water)Allow a dry pipet and acontainer of distilled water to stand at room temperature of 20to 25C for 2 h. Weigh the dry pipet and record the weight. Fillthe same pipet with water and adjust to the calibration line inTABLE 2 Dimensions for Type II Pipe
37、tStated Capacity,LMinimumLength A, mmMinimum Di-ameter B, mmMinimum WallC, mmMaximum Volumetric DeviationAccuracy, %Coefficient ofVariation, %1 20 0.5 0.20 61.5 2.02 20 0.5 0.20 61.2 1.53 20 0.6 0.20 61.2 1.54 20 0.6 0.20 61.2 1.55 20 0.6 0.20 61.2 1.510 20 0.6 0.10 61.0 1.220 20 0.6 0.10 61.0 1.225
38、 30 0.6 0.10 61.0 1.250 30 1.0 0.10 61.0 1.2100 50 1.3 0.10 61.0 1.2E 672 87 (2006)3accordance with 8.1 and 8.1.1. Then reweigh the pipet withwater content and record the weight. Record the room tem-perature. Subtract the recorded weight of the dry pipet from therecorded weight of the pipet filled w
39、ith distilled water repre-senting the apparent mass of the contained water. Calculate thevolume, V, in accordance with 9.2 and Appendix X2.9.1.3 Type IIAllow a dry pipet and a container of distilledwater to stand at room temperature 20 to 25C for 2 h. Weighthe dry pipet and record the weight. Then f
40、ill the same pipetwith distilled water, by capillary attraction with specific care toremove all water from the exterior of the pipet with a dry clothor gauze. Then reweigh the pipet with water content, andrecord the weight. Record the room temperature. Subtract therecorded weight of the dry pipet fr
41、om the recorded weight ofthe pipet filled with distilled water representing the apparentmass of the contained water. Calculate the volume, V,inaccordance with 9.2 and Table X2.NOTE 4To accurately perform the test methods outlined in 9.1.1,9.1.2, and 9.1.3, the reliability of the weighing instrument
42、used should beconfirmed against a known standard and the weighing instrument shouldpossess a minimum sensitivity that does not exceed the following:Stated Capacity Minimum Sensitivity1to5L 0.001mg10 to 200 L 0.01 mg9.2 CalculationsCalculate the volume, V, of a micropipetfrom the weighings, in air, u
43、sing the following equation:V 5 W3 Z (1)where:W = apparent mass of liquid (mercury/water), weighed inair, andZ = apparent specific volume, (mercury/water).Values of Z for mercury and water are given in AppendixesX1 and X2, respectively.9.3 Capacity Deviation (Single Pipet)In accordance withthe metho
44、ds outlined in 9.1.1, 9.1.2, and 9.1.3, using eithermercury or water, the capacity deviation is the differencebetween the stated capacity and the observed capacity of thepipet as follows:Capacity Deviation, % 5Vc2 V1! 3 100V1(2)Vc5Vt1 1 at 2 20C!where:Vt= observed volumetric capacity at tC, L,Vc= co
45、rrected volumetric capacity at 20C,a = coefficient of cubical expansion of pipet glass;0.000010/C for Type I, Class A borosilicate;0.000015/C for Type I, Class B (noncorrosive boro-silicate); and 0.000025/C for Type II, (sodalime).V1= stated capacity of pipet, andt = temperature, C.9.4 Capacity Devi
46、ation (Number of Pipets)Test a mini-mum of 30 Type I or Type II pipets, or both, taken at randomfrom a completed manufactured production lot, in accordancewith 9.1.1, 9.1.2,or9.1.3. Calculate the volumetric deviationfor the 30 pipets as follows:9.4.1 Accuracy:Accuracy, % 5100 x 2 V1!V1(3)where:x = m
47、ean of sample measurements, andV1= stated capacity of pipet.9.4.2 Coeffcient of Variation:Coefficient of Variation, % 5100sx(4)s 5(x 2 x!2n 2 1where:x = individual sample measurement,x = mean of sample measurements, andn = number of pipets measured.10. Keywords10.1 disposable; glass; micropipetsAPPE
48、NDIX(Nonmandatory Information)X1. Density and Z Factor TablesE 672 87 (2006)4ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validi
49、ty of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible techni
