Hi everyone, I had an issue on Zn analysis that I really don't understand (we use ELAN 6100), my calibration curve between 10 ppb and 50 ppb is ok (R2 = 0.999), however, my blank intensity (9,000 cps) is much lower than the intercept of that calibration curve (37,000 cps). I used Zn64, 66, and 68 to determine Zn concentration in case of possible interference on Zn64, however, this conclusion applies on all of them. I know my calibration standard is not comtaminated by other elements such as As, Fe, Cd, Mn, Pb and so on from my previous analysis, so, the only possible reason that I can think of is my calibration standard is contaminated by only Zn (is it likely a reason?), but before spending money on getting another bottle, I'm wondering does anyone has a possible reason other than Zn contamination? How likely it is? Thank you very much!