Question

Discuss the types of error observed in external standard calibration
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Answer 1

Explanation:

1. A 12.3 mM solution of analyte yields a signal of 489. A solution containing an unknown concentration of analyte yields a signal of 318. Determine the concentration of analyte in the unknown. (answer = 8.00 mM)
2. A standard solution was prepared by dissolving 25.7 ± 0.1 mg of dye to a volume of 100.00 ± 0.08 mL in a volumetric flask. Calculate the concentration of the standard solution in ppm (mg/L). (answer = 257 ± 2 ppm)
3. The absorbance of the dye standard solution in part (2) was measured 7 times in a 1.00 ± 0.01 cm cuvette, yielding an average absorbance of 0.749 ± 0.002. Determine the absorptivity of the dye in ppm-1 cm-1. (A = abc, where A is absorbance, a is absorptivity, b is path length, and c is concentration) (answer = 2.91 (± 0.04) x 10-3 ppm-1 cm-1)