爱华网Change to read:
This chapter states the requirements for balances used formaterials that must be accurately weighed (see General Notices,8.20). Unless otherwise specified, when substances must be“accurately weighed”, the weighing shall be performed using abalance that is calibrated over the operating range and meets therequirements defined for repeatability and accuracy. For balancesused for other applications, the balance repeatability and accuracyshould be commensurate with the requirements for its use.
本章说明了用于必须“精密称定”（参见凡例8.20）的物料称量的天平的要求。除非另有说明，如果必须“精密称定”，则应采用在称量范围内经过校正，并且符合重复性和准确性要求的天平来称量。对于其它用途的天平，天平的重复性和准确度应根据其用途要求来确定。
For discussion of the theoretical basis of theserequirements, see general information chapter Weighing on anAnalytical Balance 1251 , which may be a helpful—but notmandatory—resource.
关于这些要求的理论基础的讨论，参见凡例<1251采用分析天平称量>，可能会有帮助---但不是必须。
REPEATABILITY重复性
Repeatability is assessed by weighingone test weight NLT 10 times. [ NOTE —The test weight mustbe
within the balance's operating range, but the weight need not becalibrated. Because repeatability is virtually independent ofsample mass within the balance's capacity, use of a small testweight, which may be difficult to handle, is not required. ]
重复性采用对一个重量测试不少于10次来评估。【注-----用于测试的重量必须是在天平的称量范围内，但该砝码是不需要校正的。因为重复性实际上取决于天平称量能力内样品的重量，由于很小的砝码可能比较难操作，因此不一定必须使用很小的那个。】
Repeatability is satisfactory if two times the standard deviationof the weighed value, divided by the nominal value of the weightused, does not exceed 0.10%. If the standard deviation obtained isless than 0.41d , where d is the scaleinterval,replace this standard deviation with 0.41d .In this case, repeatability is satisfactory if two times 0.41d ,divided by the nominal value of the weight used, does not exceed0.10%.
如果各次所称得的重量值的标准偏差的2倍，除以所用砝码的名义重量值，不超过0.10%，则认为重复性满足要求。如果所得的标准偏差小于0.41d，这里d值是分度值，则采用0.41d替代该标准偏差。这种情况下，如果0.41d的2倍，除以所用砝码的名义重复值，不超过0.10%，则认为重复性满足要求。
ACCURACY准确度
The accuracyof a balance is satisfactory if its weighing value, when testedwith a suitable weight(s), is within 0.10% of the test weightvalue.
如果采用一个适当的砝码，其称量值与标准值的差值在标准值的+/-0.10%以内，则认为天平的准确度满足要求。
A test weight is suitableif it has a mass between 5% and 100% of the balance's capacity. Thetest weight's maximum permissible error (mpe), or alternatively itscalibration uncertainty, shall be NMT one-third of the applied testlimit of the accuracy test.
适当的砝码是指其重量在天平的最大量程的5%-100%之间的重量。测试用砝码的最大允许偏差（mpe），或其校正不确定度，应不超过所使用的准确度测试的检测限的1/3。
[ NOTE —Applicablestandards are the following: ASTM E617 (availablefromhttp://www.astm.org) and OIML R 111 (availablefromhttp://www.oiml.org). ]
【注----适用标准引用ASTM E617】
2S ( USP36 )
Auxiliary Information— Please check for your question in the FAQsbefore contacting USP.
USP36–NF31 Page53
USP36–NF31 Supplement : No. 2 Page 6136
Pharmacopeial Forum: Volume No. 38(5)
