多谢老师,很详尽
冰山(yang_qingwen)发表: 一、先算所加的镉是多少:1ml×0.05mg/L=1ml÷1000×0.05mg/L=0.00005mg=0.05ug
二、再算实际测得所加镉是多少?分为两步:
1.先算样品本身的含量是多少?25ml×0.0009mg/L÷1.5367g=25ml×0.0009ug/mL÷1.5367g≈0.0146ug/g
2.再算样品中所加镉的测得值是多少?
①求出样品加标后的总镉:25ml×0.0029mg/L=0.0725ug
②求出样品本身所含的镉:1.5237g×0.0146ug/g=0.0222ug
③求出样品中所加的镉测得量:0.0725ug-0.0222ug=0.0503ug
三、最后求出加标回收率:0.0503ug÷0.05ug×100%=100.6%