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mcfly2008

新虫 (初入文坛)

[求助] 关于检出限,如何折算到样品中去? 已有1人参与

最近投了一篇稿件,关于ICP-MS测定多元素的,审稿意见关于LOD的,以前认为算出仪器的LOD,然后折算回样品(按定容体积,称样量),就是方法的LOD,万万没想到,审稿人给了我意见如下:

However, calling it a limit of detection is not a correct use of terminology.  LOD is an instrumental terminology, it does not refer to samples.  I think you should probably find another way to explain it.

请问我该怎么想办法,折算到样品去呢?
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klicking

至尊木虫 (著名写手)

【答案】应助回帖

感谢参与,应助指数 +1
可以参考:通过几份空白样品的分析,然后计算其响应值的标准差,测出分析背景响应值的大小。
(ICH Q2(R1):6.3        Based on the Standard Deviation of the Response and the Slope
The detection limit (DL) may be expressed as:
DL =        3.3 σ/S
where        σ = the standard deviation of the response
                S = the slope of the calibration curve
The slope S may be estimated from the calibration curve of the analyte. The estimate of σ may be carried out in a variety of ways, for example:
6.3.1        Based on the Standard Deviation of the Blank
Measurement of the magnitude of analytical background response is performed by analyzing an appropriate number of blank samples and calculating the standard deviation of these responses.
6.3.2        Based on the Calibration Curve
A specific calibration curve should be studied using samples containing an analyte in the range of DL. The residual standard deviation of a regression line or the standard deviation of y-intercepts of regression lines may be used as the standard deviation.
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2楼2014-10-16 09:28:23
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51658173

新虫 (小有名气)

引用回帖:
2楼: Originally posted by klicking at 2014-10-16 09:28:23
可以参考:通过几份空白样品的分析,然后计算其响应值的标准差,测出分析背景响应值的大小。
(ICH Q2(R1):6.3        Based on the Standard Deviation of the Response and the Slope
The detection limit (DL) may ...

请问,标准偏差是根据多次测量的响应值自己计算出来的吗,还是把标曲中的截距作为平均值,再乘以标曲旁边表格中0浓度对应的RSD值,作为标准偏差呢?
3楼2016-12-23 21:29:11
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