Hi everyone. Im using the Agilent 7900 for the analysis of a bunch of analytes in water samples without any problems, except for Ag, Sb and Sn. Im having a problem with the calibration curves of these three analytes because the calibration curves are not linear, it almost seems theat I swaped the points of the calibration between each other. So of course I tried to clean every part, changed all tubings, I have new conuses, every reference material and solution are fresh. Im using macerated plastic bottles for storage of the solutions, adding HNO3 into every solution. Im using He mode, and I chose the following isotopes: Ag 107; Sn 118; Sb 121. The points of the calibration curves for the Ag and Sb are 1; 25; 50; 75; 100 ppb and for the Sn 10; 250; 500; 750; 1000 ppb. And I measure them together with the following analytes: Li, Be, B, V, Se, Sr, Mo, Ba. So I was wondering, if anyone has a similar problem. Or someone has an idea what should I try. Thank you very much.