收录 被收录1次
实验室管理 仪器与设备

歪翻USP44:<1251>应用分析天平进行称量-中

别等、别催,我是海绵,也是奶牛。若有需要,可以关注我或者这个专辑。 那个下,最早这周末~~~~~~~~~
评分 评分评分评分评分评分
阅读 312 收藏 4
手机端查看
使用微信 “扫一扫” 即可在手机上查看
Performance Qualification性能确认
Table 1 provides a list of the most important balance properties that should be assessed during performance qualification. Depending on the risk of the application and the required weighing process tolerance, some of these tests may be omitted. Tests also can be omitted if there is evidence that the property in question has only minimal effect on the weighing performance. Any procedures used should be consistent with in-house standard operating procedures, applicable for the specific balance, and adequately justified. Performance qualification should be performed periodically as described in standard operating procedures, and the frequency of each of the individual tests can vary depending on the criticality of the property.
表1列出了在性能确认期间应该评估的最重要的天平属性。根据天平使用的风险和所需的称重工艺允差,有些测试可以省略。如果有证据表明所涉及的性能对称重性能的影响很小,那么测试也可以省略。天平是使用的程序应与内部标准操作程序一致、适用于其型号,并且使用程序应是充分合理的。性能确认应按照标准操作程序的要求定期进行,每次单独测试的频率可以根据性能的关键程度而变化。
The weights that are used to perform the tests should be stored and handled in a manner that minimizes contamination. Before executing the tests, the technician should place the weights in the vicinity of the balance for an appropriate time to reach sufficient thermal equilibrium. If possible, tests should be carried out with a single test weight in order to minimize handling errors, but multiple test weights are permitted.
用于测试的砝码应以尽量减少污染的方式储存和处理。在进行测试之前,技术人员应将砝码放在天平附近适当的时间,以达到足够的热平衡。如果可能,应使用单一测试砝码进行测试,以尽量减少处理错误,但允许使用多个测试砝码。
The tests should be recorded in such a manner that the data can be used to easily track balance performance and to assist in laboratory investigations as needed. Meaningful acceptance criteria can be set depending on the required weighing tolerance, i.e., the maximum allowed deviation permitted by specifications, regulations, etc., of a quantity to be weighed from its target value. Procedures should be in place to address test results that are outside acceptable ranges and to provide assurance that balance cleanliness and environment have not affected the result. Also, a procedure should be in place for removing a balance from operation when observed results fall outside acceptable ranges.
测试记录的方式应该满足:数据可以用来方便地跟踪天平性能,并在需要时协助实验室调查的开展。有意义的验收标准可以根据要求的称重公差来设定,即,被称重的质量与目标值的最大允许偏差是由规格、法规等所允许的。应该有适当的程序来解决确认测试结果超出可接受范围的情况,并保证天平清洁和环境没有影响确认结果。此外,当观察到的结果超出可接受范围时,应该有一个程序来从受控现场移除该天平。
Table 1. Suggested Performance Tests and Acceptance Criteria
表1 建议的性能测试和验收标准(标红内容我没研究,自己去查吧,要不你告诉我?)

歪翻USP44:<1251>应用分析天平进行称量-中
Sensitivity, linearity, and eccentricity all account for systematic deviations; i.e., they limit the accuracy of the balance (based on the definition of accuracy in Validation of Compendial Procedures 1225 and ICH Q2). In the International Vocabulary of Metrology (VIM) and documents of the International Organization for Standardization, this concept is referred to as trueness. Because deviations are largely independent from each other, it is not likely that all deviations occur simultaneously and have the same algebraic sign. Therefore the arithmetic addition of all individual deviations to assess the balance accuracy would constitute a rather conservative approach. A quadratic addition of the individual deviations is a more realistic approach. By allocating 50% of the weighing tolerance budget to the acceptance criteria of the individual properties, e.g., sensitivity, linearity, and eccentricity, analysts ensure adherence to the required weighing tolerance. Therefore, the acceptance criteria for the individual properties that account for the systematic deviations are set to weighing tolerance divided by 2. These properties— or a subset of them—also can be taken to fulfill the accuracy requirement described in 41. In this case the acceptance criteria thus allow a maximum deviation of 0.05% for sensitivity, linearity, and eccentricity. Repeatability preferably is tested with a test weight of a few percent of the balance capacity. At the lower end of its measurement range, the performance of laboratory balances is limited by the finite repeatability, and limitations induced by systematic deviations normally can be neglected. Therefore, the whole weighing tolerance budget can be allocated to the acceptance criterion of the repeatability test.
灵敏度、线性和偏心率都可以解释系统偏差;也就是说,它们限制了天平的准确性(基于药典<1225>分析程序验证中准确性的定义和ICH Q2)。在国际计量词汇(VIM)和国际标准化组织的文件中,这个概念被称为真值。因为偏差在很大程度上是相互独立的,所以不太可能所有偏差同时发生并且具有相同的代数符号。因此,所有具体偏差的算术加法来评估平衡精度将构成一种相当保守的方法。具体偏差的二次加法是一种更现实的方法。通过将预期称重公差的50%分配给具体属性的验收标准,例如灵敏度、线性和偏心率,分析人员为确保遵守所需的称重公差,对系统偏差的具体属性的接受标准设置为称重公差除以2。这些属性(或它们的子集)也可以用来满足药典<41>中描述的精度要求。在这种情况下,验收标准因此允许灵敏度、线性和偏心率的最大偏差为0.05%。最好用天平量程的百分之几的测试砝码来测试可重复性。在其测量范围的低端,实验室天平的性能受到有限的重复性的限制,通常可以忽略系统偏差引起的限制。因此,整个预期称重公差可以分配给重复性试验的验收标准。
For the sensitivity and linearity tests as described above, the analyst should use certified weights with an appropriate weight class (e.g., according to International Organization of Legal Metrology R111 or American Society for Testing and Materials E617, available from www.oiml.org and www.astm.org, respectively). [NOTE—If a differential method is used for the linearity test, certified weights may not be required.]
对于上述的灵敏度和线性测试,分析师应使用具有适当重量等级的认证砝码(例如,根据国际法定计量组织R111或美国测试和材料协会E617,分别可从www.oiml.org和www.astm.org获得)。[注-如果线性测试采用微分法,则可能不需要认证砝码。]
Depending on the acceptance criterion, it may be sufficient to consider only the nominal weight value of the test weights. If the nominal value of the test weight is considered, analysts should ensure that the maximum permissible error does not exceed one-third of the acceptance criterion. Alternatively, if the certified value of the test weight is considered, its calibration uncertainty should not exceed one-third of the acceptance criterion. If more than one weight is used to perform the test, the calibration uncertainties of the weights must be summed and the sum should not exceed one-third of the acceptance criterion. For tests such as eccentricity or repeatability, the use of certified weights is optional, but analysts must ensure that the mass of the weight does not change during the test.
根据验收标准,只考虑测试砝码的标称重量值可能就足够了。如果考虑测试重量的标称值,分析人员应确保最大允许误差不超过验收标准的三分之一。或者,如果考虑测试砝码的认证值,其校准不确定度不应超过验收标准的三分之一。如果使用多个砝码进行试验,则必须对砝码的校准不确定度进行求和,其总和不应超过验收标准的三分之一。对于偏心率或重复性等测试,可选择是否使用认证砝码,但分析人员必须确保在测试过程中砝码的质量不会发生变化。
The tests described above also can be included in formal periodic calibration in order to fulfill applicable cGMP requirements.
上述试验也可以包括在正式的定期校准中,以满足适用的cGMP要求。
Balance Checks天平核查
A balance check using an external weight helps ensure that the balance meets weighing tolerance requirements. The balance check is performed at appropriate intervals based on applicable standard operating procedures. The frequency of the balance check depends on the risk of the application and the required weighing tolerance. Checks with external weights can be replaced partially using automatic or manually triggered adjustment by means of built-in weights. When analysts perform the balance check with an external weight, the same acceptance criteria may apply as described in the sensitivity test above.
使用外部砝码的天平核查,有助于确保天平满足称重允差要求。根据适用的标准操作程序,每隔适当的时间进行天平核查。核查的频率取决于天平使用的风险和所需的称重允差。采用内置砝码的自动或手动触发校准的方式,可以部分替代使用外部砝码进行的核查。当分析员使用外部砝码进行核查时,可采用与上述灵敏度测试相同的可接受标准。
Minimum Weight 最小称量值
The minimum net sample weight, in short, minimum weight, m min, of an analytical balance can be expressed by the equation: 分析天平的最小净样本质量,简而言之,最小样本质量,mmin可表示为:
m min = k × s/required weighing tolerance
m min = k × s/要求的称量允差
where k is the coverage factor (usually 2 or larger) and s is the standard deviation (in a mass unit, e.g., in mg) of NLT 10 replicate measurements of a test weight. If the standard deviation obtained is less than 0.41d, where d is the scale interval, the standard deviation is replaced by 0.41d. The lower limit of 0.41d for the standard deviation results from the rounding error of the digital indication of a weighing instrument. The rounding error that is allocated to a single reading is calculated as 0.29d. Note that a weighing always consists of two readings, one before and one after placing/removing the sample on/from the pan, with the difference between the two indications being the net sample weight. The two individual rounding errors are usually added quadratically, leading to 0.41d. Taring the instrument after placing the tare container on the pan does not affect the rounding error as the zero indication is also rounded. The minimum weight describes the lower limit of the balance below which the required weighing tolerance is not adhered to. The equation above takes into account that the performance of analytical balances at the lower end of the measurement range is limited by the finite repeatability.
其中k为安全系数(通常为2或更大),s为测试砝码的NLT 10次重复测量的标准偏差(以质量单位为单位,例如,mg)。如果得到的标准差小于0.41d,其中d为刻度间隔(分辨力),则用0.41d代替标准差。标准偏差的0.41d的下限来自于衡器数字指示的舍入误差。分配给单个读数的舍入误差计算为0.29d。注意,称重总是由两个读数组成,一个是在将样品放在/移出称量舟之前,另一个是在将样品放在/移出称量舟之后,两个指标之间的差值就是样品的净重量。两个单独的舍入误差通常是二次相加,得到0.41d。将去皮容器放在称量舟上后对仪器进行去皮并不影响四舍五入误差,因为零点指示也是四舍五入的。最小重量描述的是天平的下限,低于此下限意味着不遵守所要求的称重公差。上述公式考虑到了分析天平在测量范围低端的性能受到有限重复性的限制。
For materials that must be accurately weighed, 41 stipulates that repeatability is satisfactory if two times the standard deviation of the weighed value, divided by the desired smallest net weight (smallest net weight that the users plan to use on that balance), does not exceed 0.10%. For this criterion the equation above simplifies to:
对于必须精确称量的材料,< 41 >规定,如果称量值两倍的标准偏差除以所需的最小净重(用户计划在该天平上使用的最小净重),不超过0.10%,则重复性是令人满意的。对于这个准则,上式简化为:
m min = 2000 × s
If the standard deviation obtained is less than 0.41d, where d is the scale interval, the standard deviation is replaced by 0.41d.
如果得到的标准差小于0.41d,其中d为刻度间隔(分辨力),则用0.41d代替标准差。
If not subject to the requirements of 41, the minimum weight value may vary depending on the required weighing tolerance and the specific use of the balance.
对于非< 41 >适用的称量,则最小重量值可能会根据所要求的称重公差和天平的具体用途而有所不同。
To facilitate handling, the test weight that is used for the repeatability test does not need to be at the minimum weight value but can be larger because the standard deviation of repeatability is only a weak function of the test weight value.
为了便于处理,用于可重复性测试的测试砝码名义值不需要在最小砝码,可以更大,因为可重复性的标准差与测试砝码质量仅呈弱相关。
In order to satisfy the required weighing tolerance, when samples are weighed the amount of sample mass (i.e., the net weight) must be equal to or larger than the minimum weight. The minimum weight applies to the sample weight, not to the tare or gross weight.
为了满足要求的称重公差,在称量样品时,样品的质量值(即净重)必须等于或大于最小重量。最小重量适用于样品重量,而不是皮重或毛重。
Factors that can influence repeatability while the balance is in use include:
在使用天平时,可能影响重复性的因素包括:
1.The performance of the balance and thus the minimum weight can vary over time because of changing environmental conditions. 由于环境条件的变化,天平的性能和最小重量会随着时间的推移而变化。
2.Different operators may weigh differently on the balance—i.e., the minimum weight determined by different operators may be different. 不同的操作人员用天平的称重可能不同。例如:不同的操作人员确定的最小称量值可能不同。
3.The standard deviation of a finite number of replicate weighings is only an estimation of the true standard deviation, which is unknown. 有限个重复权重的标准差只是对真实标准差的估计,而真实标准差是未知的。
4.The determination of the minimum weight with a test weight may not be completely representative for the weighing application. 用重量称量试验确定最小重量可能不能完全代表称重应用。
5.The tare vessel also may influence minimum weight because of the interaction of the environment with the surface of the tare vessel. 由于环境与去皮容器表面的相互作用,去皮容器也可能影响最小重量。
For these reasons, when possible, weighings should be made at larger values than the minimum weight, i.e., the desired smallest net weight that the users plan to use on that balance should be larger than the minimum weight.
由于这些原因,在可能的情况下,称重时应采用大于最小重量的值,即用户计划在该天平上使用的期望最小净重应大于最小重量。
发布于 2022-09-14 23:10:25 © 著作权归作者所有
评分
评论
点赞
收藏
更多