Does anyone have an idea why my Hg blank shows higher intensity than some of my standards using ICP?MS?

I need to analyse some samples for Hg content. I have some standards ranging from 0.01 to 10 ppb. However my blank shows higher intensity than my standards rang at 0.01 to 1 ppb. I use HNO3 5% in...

09 September 2016 7,011 8 View