Gas chromatography detectors types
- 3. GC- Column
- 4. GC- Detectors 1. Flame ionization detector ( FID) 2. Thermal conductivity detector (TCD) 3. Electron capture detector (ECD) 4. Thermionic detector (TID) 5. Electrolytic conductivity detector 6. Photoionization detector (PID) 7. Atomic Emission detector (AED) 8. Flame Photometric detector (FPD) 9. GC-MS 10.GC-IR
- 5. Ideal characteristics of a detector • Adequate sensitivity • Good stability & reproducibility • Linear response • Temp range from room temp to 400⁰C • Short response time • High reliability • Selectivity • Non destructive
- 7. FID • Few hundred volts applied between burner tip and collector electrode • Resulting in generation of current Advantages: 1. High sensitivity 2. Linear response & low noise 3. Rugged and easy to use Disadvantages: 1. sample is destroyed 2. requires additional gases and controllers
- 9. TCD Advantages: 1. Simplicity 2. Response to both organic & inorganic species 3. Non destructive character Disadvantages: 1. Low sensitivity
- 11. ECD Advantages: • Selective in response • Halogens, peroxides, quinones & nitro groups are detected with high sensitivity • Detection & quantitative determination of chlorinated insecticides. • Highly sensitive, linear response Disadvantages: • Insensitive to groups like amines, alcohols and hydrocarbons
- 13. TID • Selective towards organic compounds containing phosphorous and nitrogen • Response to phosphorous is 10 times greater than nitrogen atom • TID is 500 times more sensitive to phosphorous containing compounds and 50 times more sensitive to nitrogen containing compounds when compares with FID
- 15. Electrolytic conductivity detector • Halogen sulphur and nitrogen containing compounds are analyzed in ECD • Reaction tube is made of nickel kept at temperature of 850-1000 ⁰C • Products are dissolved in conductive solution
- 17. PID • Eluent is photoionised by UV radiation from 10.2eV hydrogen or 11.7eV argon lamp. • More sensitive for aromatic hydrocarbons and organophosphorous compounds which are easily photionized
- 19. AED • Effluent is introduced into microwave induced plasma • Plasma atomizes all elements in sample • Atomized elements excite to give characteristic atomic emission spectra
- 21. FPD • Analysis of air water pollutants & pesticides • Selective to phosphorous and sulphur • P is converted into HPO which emits bands at about 510 and 526nm • S is converted to S2 which emits the band at 394nm
- 22. GC-MS
- 23. GC-IR