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14 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Two types of analysis |
Quantitative analysis: relies on interaction between radiation absorbed by sample and the component within the sample Qualitative analysis: can give valuable information regarding type, structure, and environment of component within the sample |
Both types starts with Q |
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Measurements method based on what? |
1. What kind of energy needed? Electronic, vibration, rotation, translation, nuclear 2. What kind of radiation? Absorption, emission, fluorescence 3. What kind of sample? Absorbing or non absorbing. If non-absorbing can use dye to turn it to absorbing sample |
There are 3 requirements |
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Principle of 3 commonly used instruments |
1. Absorption Uses electromagnetic wavelength (e.g: UV VIS, aas, infrared transmission) 2. Emission Analyze with stimulation, theelectron is sent to the excited state and when it comes back down to ground state, it will release light (e.g: NMR, fluorescence, atomic emission spectro) 3. Reflection Same as absorption, it uses electromagnetic wavelength but in the end it reflects (e.g: infrared reflections, color measurements) |
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What does UV-Vis detects? |
UV: detects organic molecules Vis: detects metal/ligands in subtances |
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Mention 3 instrumentations |
1. Fixed wavelength instrument 2. Scanning instrument 3. Diode array instrument |
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Fixed wavelength instrument: Light source? Does it need chromator? What wavelength? |
LED and pseudo-monochromatic No, bcuz it reads right from the result of LED 460 nm |
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Scanning Instrument: Radiation source and its wavelength |
1. Tungsten lamp: 350-2500 nm (use wolfram as filament) 2. Deuterium lamp: 200-400 nm (use wolfram but only to maintain the heat so the deuterium gas can be ignited) 3. Xenon arc lamp: 200-1000 nm (use electrical energy to create spark between anodes and catodes so the xenon gas will ignite) |
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Sample holder/cuvette used: UV? Vis? |
UV: bcuz this process involves heat and UV, it needs quartz as cuvette. Quartz contain 90% SiO2. Glass has 30% lead which is not allowed, plastic can absorb UV which is not allowed. Quartz also tahan panas and can conduct electrical energy Vis: can use glass or plastic |
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Types of Scanning Instrument Beam |
Single Beam: has to analyze sample and reference separately Dounble Beam: can analyze sample and reference together at once |
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Diode array instrument: Often used as a detector for what? Its influence on wavelength? What will it detect on wavelength? |
1. Often used as detector for HPLC method 2. It created only one single wavelength 3. The decreases of wavelength bcuz some of it is absorbed by sample |
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Advantage and Disadvantage on Scanning and Diode Array |
Scanning has result of high res but slow process and diode has low res but fast process |
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Atomic Absorption Spectrophotometer (AAS) 1. Process? 2. Instrument? |
1. The atom in gas state can absorb radiation and send the electron to excited state without vibrarional and rotational energy 2. There is hollow cathode lamp, sample in a flame burner, monochromator and detector |
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4 Methods used to vaporize sample to solution |
1. Oven: evaporized with heat from oven 2. Electric arc or spark: using high wavelength to create spark and it will evaporate the sample 3. Ion bombardment: sample will be put in catodes and will be given positive ions 4. Flame atomization: sample will be sprayed to flame |
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Detector used for UV-Vis and AAS Spectrophotometer |
Detector used is photomultiplier tube |
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