Basic of SpectrophotometrySMK Negeri 13 Bandung

Dispersion of f Polichromatic RadiationRadiation sourceVisible Ray Spectrum

Color Complementer PropertyarnaAdsorbed coor is complement of reflected colorPurple-dark blueYellowRedHijauOrangeBlue

Absorption of visible ray and color

AdsorbedRadiationReflected Color (Eye cacthed)ColorWavelength (nm)Purple-dark blue400-435YellowBlue450-480OrangeGreen500-560RedYellow585-590Purple-dark blueOrange590-605BlueRed607-770Green

REM wave

REM Spectrum

REM SpectrumExcitationSpectroscopic Method:

Electronic Molecule NucleusEnergy Vibration ResonanceUV-Vis IR NMR

Interaction of REM - MatterRadiation inDiffusion

Absorption dan EmissionElectromagnetic Emission, Radition Spectroscopic AbsorptionElectromagnetic Emission, Radition Spectroscopic EmissionGround stateExcited state

Absorption dan EmissionE= Energi (J)E= Energi Difference (J)h= Planck Constant (6,626 . 10-34 Js)c= Ligth Velocity 3 . 108 m/s= Frequence (Hz)

Absorption

The Lambert- Beers LawConcentration in mole/ literCuvette thickness in cmAbsorbance (No dimension) Molar Absorptivity In liter / mole cm

UV/VIS Spectroscopy Basic theory (Color Spectrum , Light Absorption and Lambert-Beers Law)InstrumentationApplication

Visible Spectrum High Freq.Low Freq. Wave length (nm)

Molecular OrbitalBonding MO Anti bonding MO Non bonding MO Energi equivalent to REM at 200 800 nm

Electronic TransitionAnti Bonding MO Bonding MO

Band Spectrum

Example of UV Spectrum

Prequisite for UV/Vis Absorption by substance Chromophor existence : Double bonding system(1) aromatic (delocalized double bond)(2) conjugated double bond with functional group with (+)- and (-)-M-Effect(3) triple bond

Chromophor

Chromophor

Carbonyl substance

Aucsochrom

II. Instrumentation:Block Diagram of UV/Vis spectrofotometerRadiation sourceSlotSlotDetectorPolichromatic RadiationMonochromatic RadiationCuveteSlotABA : sampleB : Reference

Double BeamUV/Vis Spectrofotometer

Monochromator:PrismLattice

DADPMTDetector

Types of cuvette

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