AISWARYA S V AC 509 GC DTETCTORS and uses.pptx

this gives a detailed description about different types of detectors used in gas chromatography

1. Submitted By AISWARYA S V (12900) 1 st year PhD. Microbiology GC DETECTORS AND THEIR USES AC 509- SPECTROSCOPY AND CHROMATOGRAPHIC TECHNIQUES IARI, Division of Agrichemicals, New Delhi

2. FLOW OF PRESENTATION 1 2 5 4 3 6

3. INTRODUCTION

4. PARTS IN GC

5. Adequate sensitivity - range 10 –8 to 10 –15 g analyte/s Good stability and reproducibility A linear response to analyte that extends over several orders of magnitude A temperature range from room temperature to at least 400 o C A short response time that is independent of flow rate High reliability and ease of use Nondestructive of sample CHARACTERSITICS OF AN IDEAL DETECTOR

6. TYPES OF DETECTORS

7. Flame Ionization Detector (FID) Thermal Conductivity Detector (TCD) Nitrogen Phosphorus Detector (NPD) Flame Photometric Detector (FPD) Electron Capture Detector (ECD) Photo Ionization Detector (PID) Electrolytic Conductivity Detector (ELCD) TYPES OF DETECTORS UNIVERSAL DETETCORS STRUCTURE SELECTIVE ELEMENT SELECTIVE

8. The FID was invented by scientist Harley and Pretorious . near universal response to organic compounds, simple construction, fast response It makes use of an oven, wherein a flame is produced by burning hydrogen gas in presence of oxygen or air . Effluent from the column is directed into a air/hydrogen flame. A definite potential difference is maintained between the two electrodes with the help of a series of batteries. Compounds with C-H bonds. A poor response for some non-hydrogen containing organics (e.g., hexachlorobenzene). Sensitivity: 0.1-10 ng FLAME IONIZATION DETECTOR

9. FLAME IONIZATION DETECTOR

10. The nitrogen–phosphorus detector (NPD) is also known as  thermionic specific detector (TSD) thermal energy is used to ionize an analyte. Compounds are burned in a plasma surrounding a rubidium bead supplied with hydrogen and air. Nitrogen and phosphorous containing compounds produce ions that are attracted to the collector. The number of ions hitting the collector is measured and a signal is generated. Selectivity: Nitrogen and phosphorous containing compounds Sensitivity: 1-10 pg NITROGEN PHOSPHOROUS DETECTOR

11. The thermal conductivity detector (TCD), also known as a katharometer, Also known as bulk property detector . Universal detector Changes in thermal conductivity, such as when organic molecules displace some of the carrier gas, cause a temperature rise in the element which is sensed as a change in resistance. The TCD is non-specific and non-destructive . Selectivity: permanent gases, light hydrocarbons etc. Sensitivity: 5-20 ng THERMAL CONDUCTIVITY DETECTOR

12. THERMAL CONDUCTIVITY DETECTOR

13. An electron capture detector (ECD) is a device for detecting atoms and molecules in a gas through the attachment of electrons via electron capture ionization . The device was invented in 1957 by James Lovelock  Trace amount determination. The ECD uses a radioactive  emitter (electrons). Sensitive toward molecules with electronegative functional groups ( halogens, peroxides, quinones, nitro groups). Insensitive towards amines, alcohols and hydrocarbons. Electronegative compounds capture electrons resulting in a reduction in the current. Sensitivity: 0.1-10 pg (halogenated compounds); 1-100 pg (nitrates); 0.1-1 ng (carbonyls) ELECTRON CAPTURE DETECTOR (ECD)

14. ELECTRON CAPTURE DETECTOR (ECD)

15. It is selective towards compounds containing sulphur and phosphorous The eluent is passed into the flame, which converts phosphorous to HPO and sulphur into S 2 These excited species emit light as they luminescene in the flame. Compounds containing phosphorus are detectable with the 526nm filter, which is yellow on one side . The 394nm filter (blue on one side) allows detection of sulfur-containing compounds . Sensitivity:10-100pg(sulfur),1- 10pg(phosphorus) FLAME PHOTOMETRIC DETECTOR

16. The selective determination of aromatic hydrocarbons or organo-heteroatom species. This device uses ultraviolet light as a means of ionizing an analyte exiting from a GC column. The ions produced by this process are collected by electrodes. The current generated is therefore a measure of the analyte concentration. Sensitivity: 25-50 pg (aromatics); 50-200 pg (olefins). PHOTO IONIZATION DETECTOR

17. GCMS is hyphenated technique Separation capabilities of chromatography are combined with qualitative and quantitative detection capabilities of spectroscopy Powerful detector of GC. Measures mass to charge ratio of ions produced from sample Compounds are bombarded with electrons or gas molecules. Compounds fragment into characteristic charged ions or fragments. The resulting ions are focused and accelerated into a mass filter The abundance or number of ions per scan is plotted versus time to obtain the chromatogram. Selectivity : Any compound that produces fragments within the selected mass range. MASS SPECTROMETER

18. MASS SPECTROMETER

19. CONCLUSION

20. Sevcik JG. Detectors in gas chromatography. Elsevier; 2011 Oct 10. Lovelock JE. A sensitive detector for gas chromatography. Journal of Chromatography A. 1958 Jan 1;1:35-46. https://www.drawellanalytical.com/what-are-different-types-of-detectors-used-in-gas-chromatography-and-how-to-choose-right-one . REFERENCES

21. Thank You