# Exp: 06 Sec: # 51
Abdullah Barashid
236343
Dec 4th 2006
Omar Bugshan
236287
Title:
DETERMINATION OF METAL IONS IN A MIXTURE (And the Study of Interference Effects in Inductively Coupled Plasma Spectrophotometry)
Objective:
"To determine the concentration of calcium, manganese, and copper in a mixture solution by ICP, and the effect of Al+3 on the determination of calcium suing ICP spectrometry."
Equipment & Apparatus:
Inductively Coupled Plasma Spectrophotometer: Perkin Elmer Burette 50 mL Pipette 10 mL Beakers 150 mL Volumetric flask 100 mL / 50 mL
Reagents & Chemicals: Stock standard solutions (Ca2+, Mn2+,Cu2+,Na+, and Al3+) each containing 1000 ppm
Data:
Intensity conc. ppm 0 5 10 15 20 unknown Ca2+ 319 28979 57904 40993 112042 156345 Mn2+ 21 121 284 212 453 251 Cu2+ 2 2282 4772 3360 9242 5016.4 Ca2+ ppm 5 5 5 5 5 5 Na+ ppm 0 4 10 50 100 500
Ca2+ ppm 3 5 4 4 5 5
Al3+ ppm 0 4 10 50 100 500
E ffect of Al on Ca
6 5 Ca (ppm) Ca (ppm) 4 3 2 1 0 0 100 200 300 Al (ppm) 400 500 600 6 5 4 3 2 1 0 0 100
Effect of Al on Ca
200
300 Al (ppm)
400
500
600
Calculation & Analysis: Ca2+ Al3+ Na+ : 1000 x ppm (10 ml / 100 ml) = 100 ppm : 2.5 ml aliquots x 100 ppm / 50 ml 5 ppm : 1000 ppm x ( 0, 0.2, 0.5, 2.5, 5, 25) ml / 50 ml : 0, 4, 10, 50, 100, 500 ppm : 1000 ppm x ( 0, 0.2, 0.5, 2.5, 5, 25) ml / 50 ml : 0, 4, 10, 50, 100, 500 ppm (all six flasks)
Conclusion: Aluminum and Sodium are serious interfering species in the determination of calcium using flame emission or absorption Spectrophotometry. Aluminum forms an inter metallic compound with calcium in the flame, and sodium will provide electrons to the calcium ion to stabilize; in which both will produce a compound (a refractory material) that does not decompose at the ordinary flame temperatures. Thus, the number of atoms available for emission/absorption will decrease leading to a decrease in the signal, hence the final output. However, when a highly energetic source such as the ICP is used as an atomizer, it will provide energy high enough to decompose the refractory compounds. Thus, the interfering effect will be minimized, if not eliminated. This experiment demonstrates
the absence of interference effect when aluminum/sodium exists in the matrix of calcium ions solution.