Due Today:
1 . Iron Content
Analysis PreLab
IRON CONTENT
ANALYSIS
2. Neutralizing
Power of
Antacids Formal
Lab Report
Homework:
1. Iron Content
Analysis Short
Report
2. Prepare for
Laboratory Final
OBJECTIVE
Introduction to ultraviolet-visible
(UV-Vis) spectroscopy
Introduction to analytical chemistry
Determine the iron content in vitamin
tablets
KEY TERMS
Visible Range: 700-400 nm
UV Range: 10-400 nm
KEY TERMS
Spectroscopy – measuring the interaction
of radiation with matter
Unique wavelength for each substance
Scanning – determine wavelength with maximum
absorption
Chemists are most interested in the
electromagnetic spectrum between 190-900 nm
KEY TERMS
Beer-Lambert Law - Absorbance of a solution
is linearly related to concentration and
identity of the chemical in solution
𝐴 = 𝑏𝑐
A: absorbance
b: extinction coefficient
c: concentration
PROCEDURE NOTES
Use Volumetric Glassware
Volumetric flask
Graduated pipets
Burets
Use stock solutions dispensed from burets
PROCEDURE NOTES
Wipe off the cuvette with a Kim-Wipe before
inserting into the Spectrophotometer
Record the absorbances!
Record the advertised Iron content from
both vitamin bottles!
WASTE
Solutions can be disposed of down the
drain
RISK ASSESSMENT
Hydrochloric Acid
 Danger
 Inhalation Hazard
 Corrosive
RISK ASSESSMENT
Hydroquinone
 Danger
 Harmful if Swallowed
 Skin Irritant
RISK ASSESSMENT
o-phenanthroline
 Danger
 Toxic if swallowed
CALCULATIONS
𝑀1 𝑉1 = 𝑀2 𝑉2
Molarity units: mg of Fe/100 mL
 [Stock solution]= 40 mg/L=4 mg/100mL
V 1= volume of stock iron solution in each trial
V 2=100 mL (total volume)
CALCULATIONS
Graphing in Excel
Force the trendline through (0,0)
Include the equation of the tendline and R 2 value
Y = mx
A = bc