1. (a) List THREE (3) advantages of internal standardization method than normal calibration (b) Compare the techniques of Atomic Absorption Spectroscopy (AAS) and Inductively coupled plasma-optical emission spectroscopy (ICP-OES), in terms of their sensitivity, Give ONE (1) example of element 2. A graphite furnace atomic absorption spectrophotometer (AAS) was used to determine the arsenic (As) concentrations in drinking water. A large set of blank samples yielded an average blank signal of 0.013 and a blank standard deviation of 0.0030. The following data were obtained for a calibration curve. 2.0 4.0 6.0 8.0 10.0 [As] (ppm) Absorbance 0.12 0.28 0.48 0.53 0.72 Using a spreadsheet on an Excell, create a graph of the data using symbols only for the data points. Plot the line on the same graph and include the graph to this question. Answer the following questions (a). What is the sensitivity of the method? [1 ml ib) Calculate the LOD and LOQ for As, 11 ml (c). A sample of Water yielded an abscxtrance of 0.43. What is the encentration of As in the water? [1 m) 3. The nickel level in a soil sample was determined using AAS A 3.0 sample was dissolved in acid and then diluted to a total volume of 100.0 mL. The absorbance of this solution determined at a wavelength of 232 nm, was found to be 0.3. Several standard solutions were tested under the same conditions and a calibration curve shown below was obtained. Cakulate the mass of nickel in mg. y-0.650.00 0.9 O. 0.7 0.6 0.5 Absorbance 03 . 01 0 0 2 4 10 22 14 INI. ppm