Research Iron ions in the body are mainly present

Research Question:
What are the percent concentrations of Fe3+ ions by mass in fresh
parsley and spinach leaves?

Scientific Concept

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            Colorimeter
measures the absorbance of light by the chemical substances at a certain
wavelength. By measuring the absorbance, the concentration of a chemical
substance can be determined. For the calibration of the colorimeter, different
concentrations of a standard solution and a control (distilled water) are
prepared in cuvettes. These cuvettes are put into the colorimeter one by one to
calibrate it. After the colorimeter is calibrated, solutions of the substances
which their concentrations are wanted to be determined, are put into cuvettes
and their concentrations can be determined by this process (Dubey 209).

Purpose

            My purpose in
choosing this topic is that there is a common misconception that spinach
contains very high amount of Fe3+ ions in it but there are many
other foods that contain more Fe3+ ions than spinach. I wanted to
search that whether parsley is one of the foods that contain more Fe3+
ions than spinach.

Background
Knowledge

            Raw leaves
of fresh parsley contains 5.2mg Fe3+ ions and spinach contains 1.9mg
Fe3+ ions per 100g fresh plant (Oborn 199). Iron ions in the body are
mainly present in the red blood cells that carry oxygen to the cells through
blood. Also iron ions are used in the process of ATP production. Excess amount
of iron ions in the body are stored in liver, spleen, bone marrow and muscles.
The lack of iron ions in the body lead to anemia, which causes weakness and
weariness for the human body (“Iron”). The recommended amount of iron ions for
women at age of 11-50 is 18mg per day and for men older than 19 years is 10mg
per day. Ascorbic acid assists the absorption of iron ions of the body. But the
composition of different foods doesn’t affect the amount of iron ions absorbed
by the human body (National Research Council 367-368).

Solutions at a certain
concentration can be prepared by first determining, then measuring the mass of
the desired amount of the solute and then putting it into a volumetric flask
that has the same volume with the desired volume of the solution. Then the rest
of the volumetric flask is filled with solvent until the volume mark.

 

Variables:

Independent Variable: Percent concentration of Fe3+
ions by mass in the solutions of ashes of

2.0000g fresh spinach and parsley
leaves.

Dependent Variable: Absorbance of the solutions of ashes of
2.0000g fresh spinach and parsley

leaves.

Controlled Variable: Wavelength of the light in the
colorimeter.

Relationship à When the concentration of Fe3+ ions of a
solution is more, the absorbance of that solution is more too when the
wavelength of the light in the colorimeter is kept constant.

 

Hypothesis:
Percent concentration of Fe3+ ions by mass in fresh parsley leaves is
more than the percent concentration of Fe3+ ions by mass in spinach
leaves.

 

Materials

Apparatus

·        
7 100mL volumetric flasks

·        
8 10mL pipettes

·        
Pipet pump

·        
2 Crucibles

·        
Pipe-stem triangle

·        
Stand

·        
11 small test tubes

·        
2 Stirring rods

·        
2 10mL Graduated cylinders

·        
2 Funnels

·        
Filter paper

·        
9 Cuvettes

·        
Tongs

·        
Test tube holder

·        
Weighing dish

·        
10 Droppers

·        
Wash bottle

·        
Spatula

·        
Bunsen burner

·        
4 decimal place electronic balance

·        
Colorimeter

Chemicals

·        
FeCl3

·        
0.1M KSCN

·        
Distilled water

Procedure

Preparing the standard solutions:

1.     
Measure 1.7000g FeCl3 in a weighing
dish by using an electronic balance and spatula.

2.     
Put FeCl3 into a 100mL volumetric
flask and add distilled water until the middle of the flask, then invert the
flask several times for FeCl3 to dissolve in water.

3.     
Add water until below the 100mL mark, then
continue adding by using a dropper paying attention to the meniscus. Label the
volumetric flask “1%” FeCl3 solution.

4.     
Take 10mL from 1% FeCl3 solution by
using a pipette and put it into another 100mL volumetric flask. Add distilled
water until the middle of the flask, then invert the flask several times for
FeCl3 solution to mix with water.

5.     
Add water until below the 100mL mark, then
continue adding by using a dropper paying attention to the meniscus. Label the
volumetric flask “0.1%” FeCl3 solution.

6.     
Repeat steps 4 and 5 to prepare 0.01%, 0.001%,
0.0001%, 0.00001% and 0.000001% FeCl3 solutions by taking 10mL from each
sample in the previous volumetric flask.

7.     
Take 5mL from each standard solution by using pipette
and put the solutions into test tubes.

8.     
Add 5mL KSCN solution in the test tubes by using
a pipette, shake the test tubes slowly to mix FeCl3 solution and
KSCN solution.

9.     
Transfer FeCl3 and KSCN mixtures into
cuvettes by using droppers, be careful to hold the cuvettes from the ribbed
sides and don’t leave any bubbles in the cuvettes, then measure the absorbance
of the solutions by using a colorimeter.

Preparing the samples:

1.     
Put the empty crucible on the pipe-stem triangle
and heat it with the hottest flame for 2 minutes, then take the crucible by
using tongs and leave it to cool down.

2.     
Measure 2.0000g parsley leaf in a crucible by
using an electronic balance.

3.     
Put the crucible on the pipe-stem triangle.

4.     
Light the Bunsen burner, turn to blue flame and
heat the crucible until the parsley burns completely.

5.     
Take the crucible from the pipe-stem triangle
and leave it to cool down.

6.     
Transfer the ash of parsley into a test tube by
using a stirring rod.

7.     
Measure 5 mL distilled water by using a
graduated cylinder with a dropper and add distilled water into the test tube,
stir it with a stirring rod.

8.     
Put an empty test tube into a test tube holder.

9.     
Put filter paper into a funnel and put the
funnel into the test tube in the test tube holder.

10.  Filter
the distilled water-ash mixture.

11.  Put
5 mL KSCN solution into the test tube that the filtrate is in by using a
pipette.

12.  Transfer
the water-ash-KSCN mixture into a cuvette by using a dropper.

13.  Repeat
steps 1-12 for spinach leaf.

Using the colorimeter:

1.     
Connect the colorimeter to your computer.

2.     
Adjust the absorbance of the colorimeter to
450nm.

3.     
Approximately 15 minutes after you have prepared
your standard solutions, start measuring the absorbance of the standard
solutions by starting from the most dilute standard solution to obtain the
calibration curve.

4.     
Measure the absorbance of parsley and spinach
samples.

5.     
Calculate the amount of Fe3+ ions in
parsley and spinach samples.

 

Works Cited

Brooks, David W. “Simple Iron in Food Determination.” Web. 6 Dec.
2017.

“Determination of Iron by Thiocyanate
Colorimetry.” Canterbury.ac.nz. 2017. Web. 6 Dec. 2017.

Dubey, R. C. Advanced Biotechnology: For B Sc and M Sc Students of Biotechnology and
Other

Biological Sciences. S Chand, 2014. Print.

“Iron.” University
of Maryland Medical Center. 23 June 2015. Web. 27 Dec. 2017.

National Research Council. Diet and Health: Implications for Reducing
Chronic Disease Risk.

1989. Print.

Oborn, Eugene T. Iron Content of Selected Water and Land Plants. United States Government

Printing Office, 1960.
Print.