Standard addition graph Tooth enamel consists mainly of the mineral calcium hydroxyapatite, Ca₁₀(PO₄)₆(OH)₂. Trace elements in teeth of archeological specimens provide anthropologists with clues about diet and diseases of ancient people Students at Hamline University used atomic absorption spectroscopy to measure strontium in enamel from extracted wisdom teeth Solutions were prepared as in Figure 58 with a constant total volume of10.0 mL containing 0.765 mg of dissolved tooth enamel plus variable concentrations of added Sr.

 

The Calibration Graph The Calibration Table Signal Added Sr 80 (ng/ml = ppb) %3! 60 28.1 Core Pok Ata 40 2.5 38.6 49 y = 4.148x + 28.18 7.5 59.3 5. 10 10 69.6 -10 -5 Added Sr (ng/ml = ppb) (a) Find the concentration of Sr in the 10-ml sample solution in parts per billion = ng/mL. (b) Find the concentration of Sr in tooth enamel in parts per million = ug/g. %3D %3D jeusis