AS8 ANALYSIS OF MINERAL TABLETS BY ICP Last Revised: May 2015 1. REAGENTS & EQUIPMENT 1.1
1000 mg/L Fe, Zn & Mn 1.2
Mineral tablets with 1‐5 mg of each of the analytes 1.3
5M HNO3 2. PROCEDURE 2A. Prework Using the 1000 mg/L standards, develop a scheme to prepare mixed standards of 1, 10 and 50 mg/L of Fe, Mn & Zn. 2B. Sample & standard preparation 2.1 Weigh three tablets together and calculate the average mass. 2.2 Transfer to a mortar and grind into powder. 2.3 Weigh accurately an amount equivalent to 75% of the average tablet mass into each of three 150 mL beakers labelled S1, S2 and S3. 2.4 Add 5M HNO3 (20 mL) to each beaker. 2.5 Swirl the contents well and boil gently on a hotplate for 5 minutes. Ensure that the solutions do not boil dry. 2.6 Transfer each quantitatively to 100 mL volumetric flasks and make up to volume with distilled water. 2.7 Filter about 50 mL through #1 filter paper, and then by Millepore before use in the ICP. 2.8 Prepare the standards as per Prework. 2C. Analysis 2.9
Measure the intensity of each analyte in each solution. REPORT Calculations 1.
Plot a calibration graph for each analyte. 2.
Determine the concentration of each analyte in each sample. 3.
Calculate the mass of each analyte in each sample. 4.
For each analyte, determine the mass/tablet using the formula below. analysedmass step3
Masspertablet xaveragetabletmass samplemass
5.
Calculate the average mass/tablet of each analyte. Discussion  comment on the results compared to the expected values  comment on the recovery check value Questions 1.
What health problems would be caused by deficiencies of the elements analysed in this exercise? 2.
Why is ICP a superior technique for this analysis to AAS? AS8 p2 AS8. ANALYSIS OF MINERAL TABLETS BY ICP & FAST AAS
RESULTS SHEET
Masses (g) Mass of 3 tablets Avge tablet mass S1 S2 S3 Intensities Fe Mn Zn Blank 1 mg/L 10 mg/L 50 mg/L S1 S2 S3 AS8 p3