11

Why used FTIR

非破壞性分析 , 操作簡單 , 分析快速樣品直接分析 , 幾乎勿需前處理 配合資料庫搜尋 ,可作未知物分析可利用化學官能基強度或光譜特性變化 , 來做定量分析無需化學試劑 , 無環境污染問題 , 安全無污染

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Introduction: The Electromagnetic Spectrum

Increasing Energy

RadioMicroFIR IRNIRUVX-rayGamma

4000 400 cm-112,82050,000

25 000 nm2500780380200

Increasing Wavelength

K-shell electrons

Outer-shell electrons

Molecular vibrations

Molecular Rotation

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Infrared (IR) Spectroscopy….

-C-H 2850-2960 cm-1

-C=O 1640-1750 cm-1 =C-H 3020-3100 cm-1 -C-O 1050-1150 cm-1

-C=C- 1650-1670 cm-1

-O-H 3400-3640 cm-1

-C-Cl 600-800 cm-1 -N-H 3310-3500 cm-1

-C-Br 500-600 cm-1

Vibration frequencies are influenced by• Atom Size• Environment• Bond Strength

O

H H

….provides a vast amount of chemical information

IR Spectroscopy measures the radiation absorbed by IR Spectroscopy measures the radiation absorbed by materials due to molecular vibrationsmaterials due to molecular vibrations

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Why Use Infrared Spectroscopy?

Fourier Transform InfraRed (FT-IR) spectroscopy is an extremely powerful technique for identifying the molecular composition of many organic and inorganic materials. When analysed by infrared spectroscopy, materials produce a spectrum or fingerprint.