Atomic Absorbance Synthesis

Determination of Trace Amount of Copper and Zinc in an Aqueous Solution by Atomic Absorbance Spectroscopy
Abstract: The purpose of this experiment is to analyze a sample containing copper and zinc in trace amounts, where standard addition method was used and the instrument used is the atomic absorbance spectroscopy. The amount of copper obtained was 0.569 ppm ± 0.015 and for zinc we obtained 0.42 ppm ± 0.0027.
Introduction: This method implies the excitation of particles in the solution sample and determination of the amount of radiation liberated from that particle to come back to its stable state. Thus the amount of radiation absorbed is related to the concentration of the sample. Inside the instrument, the sample is drawn into the burner
0 | 0.013 | 0.012 | 0.013 | 0.012667 | 0.042 | 0.042 | 0.042 | 0.042 | 0.1 | 0.02 | 0.02 | 0.02 | 0.02 | 0.077 | 0.076 | 0.076 | 0.076333 | 0.1 | 0.02 | 0.02 | 0.02 | 0.02 | 0.077 | 0.076 | 0.077 | 0.076667 | 0.1 | 0.02 | 0.02 | 0.02 | 0.02 | 0.076 | 0.076 | 0.077 | 0.076333 | 0.2 | 0.028 | 0.028 | 0.028 | 0.028 | 0.108 | 0.109 | 0.109 | 0.108667 | 0.2 | 0.028 | 0.028 | 0.029 | 0.028333 | 0.111 | 0.109 | 0.11 | 0.11 | 0.2 | 0.028 | 0.029 | 0.029 | 0.028667 | 0.111 | 0.11 | 0.111 | 0.110667 | 0.3 | 0.036 | 0.036 | 0.036 | 0.036 | 0.144 | 0.144 | 0.143 | 0.143667 | 0.3 | 0.036 | 0.036 | 0.036 | 0.036 | 0.146 | 0.143 | 0.141 | 0.143333 | 0.3 | 0.036 | 0.036 | 0.036 | 0.036 | 0.144 | 0.144 | 0.145 | 0.144333 | 0.4 | 0.043 | 0.043 | 0.043 | 0.043 | 0.174 | 0.176 | 0.175 | 0.175 | 0.4 | 0.043 | 0.043 | 0.043 | 0.043 | 0.176 | 0.177 | 0.176 | 0.176333 | 0.4 | 0.043 | 0.043 | 0.043 | 0.043 | 0.177 | 0.178 | 0.176 | 0.177 | 0.5 | 0.051 | 0.05 | 0.051 | 0.050667 | 0.211 | 0.216 | 0.215 | 0.214 | 0.5 | 0.05 | 0.051 | 0.05 | 0.050333 | 0.209 | 0.21 | 0.211 | 0.21 | 0.5 | 0.05 | 0.051 | 0.05 | 0.050333 | 0.209 | 0.209 | 0.211 | 0.209667 |

Slope | intercept | | 0.075556 | 0.012889 | | 0.000497 | 0.00015 |
The amount of copper obtained was 0.569 ppm ± 0.015 and for zinc we obtained 0.42 ppm ± 0.0027. For the slope and intercept of graph of copper absorbance for different concentration was 0.0755 as slope and 0.01289 as intercept and for zinc the slope was 0.337 and the intercept was 0.0421. In order to find the concentration of the unknown, the intercepts were assumed to be zero. The advantage of measuring many samples is that it gives a better fit for the curve that allows finding the slope and intercept. The solution containing both copper and zinc were run through the instrument to find the radiation absorbed using for copper the six element hollow cathode lamp containing some copper and same for zinc measurement. The disadvantage however is that if one sample has error, all other measurement follows the error and therefore the best fit is disturbed. The source of error for this experiment is most likely to come from the pipetting, where the last drop would fall before reaching the target