小中大【转载】【讨论】如何理解ICP期间核查的BEC和CV？
Background Equivalent Concentration (BEC)
背景值
1.1 The BEC value is the concentration of an element, which would produce the
same emission intensity as the plasma background measured at the analyte
wavelength. The BEC serves as an indication of instrument sensitivity which is
related to torch alignment, plasma viewing height, nebulizer gas flow rate, and
incident RF power.
背景值是测量一浓度元素在分析波长下产生相应的发射强度。BEC可指示仪器的
灵敏度，它与炬管线性、等离子观测的高度，雾化气流量，射频功率有关。
1.2 The BEC should be determined every three months
BEC应每3个月测定一次。
1.3 Measure the intensity of a 5% nitric acid blank solution (IB).
测量5%的硝酸空白溶液的强度（IB）。
1.4 Measure the intensity of a 1.0 ppm Mn standard in 5% nitric acid (ISTD)at
a wavelength of 257.610.`
在波长为257.610nm处测量基体为5%硝酸的1.0ppm Mn标准溶液的强度。
1.5 Calculate the BEC = IB / (ISTD – IB) X CSTD
计算 BEC = IB / (ISTD – IB) X CSTD
Where: CSTD = concentration of Mn STD = 1.0 ppm
这里： CSTD=Mn 标准溶液浓度 = 1.0 ppm
IB and ISTD have been automatically corrected to the dark
current
IB和ISTD 已经被暗电流自动校正
Record the BEC value. The BEC must not be greater
than 0.04.
记录BEC的值。BEC不能大于0.04。
1.6 If the BEC is greater than 0.04, check the sample introduction system and
the torch for wear. Replace the torch and/or change o-rings and other worn
parts as needed. Reanalyze the BEC by following steps §2.5.1.1.3 to
2.1If the BEC still does not meet the acceptance limit, notify a
supervisor immediately and take the instrument out of service.
如果BEC大于0.04，检查进样系统和炬管装置。根据需要更换炬管和/或O形圈和
其他损耗部件。按照步骤§2.5.1.1.3至2.5.1.1.5重新分析BEC。如果BEC仍然
不符合接受限值，立即通知监管者和将仪器外修。
2.1.1The BEC shall be charted to show any trending.
BEC应该标记显示出任何的变化趋势。
Notice: For PE ICP instrument, the dark current is obtained by closing the shutter.
注意： 对于PE的ICP，通过关闭快门获得暗电流。
2.1.2Coefficient of Variation Determination
变异系数的测定
2.1.3 The Coefficient of Variation (CV) indicates the precision of the instrument's
analyte emission intensity or concentration measurements. A high CV is
usually indicative of a problem with the sample introduction system such as
improper drainage, leaks, improper tension on the pump tubing, worn pump
tubing, worn o-rings, or nebulizer problems.
变异系数（CV）表明该仪器的分析物的浓度或强度精密度。高的CV 通常是表
明进样系统的有问题，如排水不当、泄漏、泵管不正确的拉紧、泵管磨损、O
型圈磨损或雾化器问题。
2.1.4The CV should be determined every three months.
CV每三个月确定一次。
2.1.5 Measure the intensity of a 5% nitric acid blank solution.
测量5%硝酸空白溶液的强度。
2.1.6 Change the number of replicates in the instrument parameters from 2 to 10.
在此仪器参数下重复测试2-10次。
2.1.7 Measure the intensity of a 1.0 ppm Mn standard in 5% nitric acid.
测量基体为5%硝酸的1.0ppm Mn标准溶液的强度。
2.1.8 Record the CV as calculated by the instrument. The CV must not be greater
than 1.00%.
记录仪器计算的CV值。CV不得大于1.00%。
2.1.9If the CV is greater than 1.00%, check the sample introduction system, replace
parts as needed and rerun the CV.
如果CV大于1.00%，检查进样系统，替换需要替换的部件和重新测试CV。
2.1.10 If the CV is still greater than 1.00%, notify a supervisor immediately and take
the instrument out of service.
如果CV仍然大于1.00%，立即通知监管者和将仪器外修。
大家在日常ICP期间核查时候考虑过吗？是如何理解BEC与CV这两个概念的？
