Spectrophotometry Notes
A spectro operates by measuring the transmittance of a sample.
UV Light:
- UV light detects colorless molecules.
- VIS spectrophotometry uses white light to find colorful molecules.
They are used similarly to detect the amount of light that goes through a sample to know
the absorbance of a given sample. You need to know the basics of how to use this machine.
UV spectrum: 100–350 nm (can measure DNA)
VIS spectrum: 350–700 nm to view colored molecules and their maximum absorbance, to
compare to the rest of the colors.
pH:
- pH < 7 has more H⁺ ions (acid)
- A base contains more OH⁻ ions
pH scale ranges from 0–12 showing relative concentrations of H ⁺ and OH ⁻ ions.
OH⁻ concentrations:
10⁻¹⁴, 10⁻¹³, 10⁻¹², 10⁻¹¹, 10⁻¹⁰, 10⁻⁹, 10⁻⁸, 10⁻⁷, 10⁻⁶, 10⁻⁵, 10⁻⁴, 10⁻³, 10⁻²
H⁺ concentrations:
1, 10⁻¹, 10⁻², 10⁻³, 10⁻⁴, 10⁻⁵, 10⁻⁶, 10⁻⁷, 10⁻⁸, 10⁻⁹, 10⁻¹⁰, 10⁻¹¹, 10⁻¹²
A spectro operates by measuring the transmittance of a sample.
UV Light:
- UV light detects colorless molecules.
- VIS spectrophotometry uses white light to find colorful molecules.
They are used similarly to detect the amount of light that goes through a sample to know
the absorbance of a given sample. You need to know the basics of how to use this machine.
UV spectrum: 100–350 nm (can measure DNA)
VIS spectrum: 350–700 nm to view colored molecules and their maximum absorbance, to
compare to the rest of the colors.
pH:
- pH < 7 has more H⁺ ions (acid)
- A base contains more OH⁻ ions
pH scale ranges from 0–12 showing relative concentrations of H ⁺ and OH ⁻ ions.
OH⁻ concentrations:
10⁻¹⁴, 10⁻¹³, 10⁻¹², 10⁻¹¹, 10⁻¹⁰, 10⁻⁹, 10⁻⁸, 10⁻⁷, 10⁻⁶, 10⁻⁵, 10⁻⁴, 10⁻³, 10⁻²
H⁺ concentrations:
1, 10⁻¹, 10⁻², 10⁻³, 10⁻⁴, 10⁻⁵, 10⁻⁶, 10⁻⁷, 10⁻⁸, 10⁻⁹, 10⁻¹⁰, 10⁻¹¹, 10⁻¹²
