Analysis of Silver Ions Using Atomic Absorption Spectroscopy

This past Friday, I was finally able to use the Atomic Absorption instrument following delays due to the hurricane. To determine the quantity of ions in my samples collected from high-alpine lakes, I first constructed a Beer’s Law calibration curve. I was unsure where my concentrations would lie so my initial curve consisted of 0.1 ppm, 10 ppm, and 100 ppm samples. I then analyzed my first sample and found the absorbance to be on the lower end of the range so I added a 1 ppm and 5 ppm standard to my curve. Upon analyzing the rest of my samples, 12 were below the limit of detection and the other two had concentrations of ~2 ppm.

The specific technique I used was Flame Atomic Absorption (FAA), and while this is a highly sensitive method, it is only useful for concentrations in ppm and above. That is why some of my samples were not detected. To analyze concentrations of ppb and below, a better technique is Graphite Furnace Atomic Absorption (GFAA). However, this is beyond the scope of my project as my goal was to see if these concentrations pose an environmental threat.

Overall, while I would have liked to see more scientifically pertinent results (concentrations that actually registered), it is a very good sign that cloud seeding does not yet pose a threat to the environmental integrity of the Wasatch Mountains.aa

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