The Effect of Iron Concentration and Luminol Temperature on the Chemiluminescence of the Luminol Test

The objective of this experiment was to find out which factor in the luminol test – temperature of luminol solution or iron nitrate (Fe(NO3)3) – has the greatest effect on the results of the test, which is the brightness of the glow.  To accomplish this task, over 40 luminol tests were performed.  In each test, a different sample of each factor was used.  Trials were tested at  low and high temperatures of luminol solution at 0°C and 40°C,respectively, and the different samples of Fe(NO3)3 were at low and high molarities of 0.15 M and 0.29M.  These trials were compared to standard trials with a temperature of 20°C and a molarity of 0.22 M.

The results of the experiment were close to what was expected.  The concentration of the Fe(NO3)3 had a positive effect on the brightness; the higher the concentration, the brighter the glow.  The temperature of the luminol solution had the same type of effect, but in reverse; the higher the temperature, the dimmer the glow.  Though each factor was proven to have an effect, neither was proven to be significant.

The results of this experiment are informative mainly to police departments and crime scene investigators.  By manipulating the factors in this way, it shows that the blood of anemic people and people with high iron levels will change the results of a luminol test, but not to the point of not detecting blood at a crime scene.  The same can be said for the temperature of the luminol solution.  The temperature of the luminol tests performed in a hot or cold environment will not significantly change the results of the test.

Research Done By:

Taylor Goodfellow
Centerline High School

Emily Pawlowski
Cousino High School