问题1：进空白溶液、供试品溶液、供试品加标溶液后作出标准加入法最小线性二乘法标准曲线后，如果再进一针供试品溶液，能测出这针供试品溶液含有目标元素的浓度吗？ 问题2：针对美国药典，标准加入法的定量限应该怎么做？不低于6份重复测定空白溶液的SD值，是吸光度的SD还是校准浓度的SD？ 美国药典关于AAS的验证定量限描述： The limit of quantitation (QL) can be estimated by calculating the standard deviation of NLT six replicate measurements of a blank solution, divided by the slope of a standard curve, and multiplying by 10. If validating a procedure using the method of standard additions, the slope of standards applied to a solution of the test material is used. A measurement of a test solution prepared from a representative sample matrix spiked at the estimated QL concentration must be performed to confirm accuracy. If validating a procedure using the method of standard additions, the validation criterion applies to the final experimental result, not the spike recovery of the individual standard addition levels. Validation criteria: The analytical procedure should be capable of determining the analyte precisely and accurately at a level equivalent to 50% of the specification.