51. How does a PID work? 100.0 ppm Gas enters the instrument It passes by the UV lamp It is now “ ionized” Charged gas ions flow to charged plates in the sensor and current is produced Current is measured and concentration is displayed on the meter. + - + - + - + - + - Gas “Reforms” and exits the instrument intact An optical system using Ultraviolet lamp to breakdown vapors and gases for measurement Photo Ionization Detector
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56. What does a PID Measure? 8 9 10 11 12 13 14 15 8.4 9.24 9.54 9.99 10.1 10.5 10.66 11.32 11.47 12.1 14.01 Some Ionization Potentials (IPs) for Common Chemicals Benzene MEK Vinyl Chloride IPA Ethylene Acetic Acid Methylene chloride Carbon Tet. Carbon Monoxide Styrene Oxygen Ionization Potential (eV) 11.7 eV Lamp 10.6 eV Lamp Not Ionizable 9.8 eV Lamp
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62. Selectivity Vs Sensitivity No Correction Factor is used until compound is identified Identify then Quantify!
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92. Integrating Gas Detection Techniques The Gas Monitoring Pyramid is a graphic depiction of how to integrate various gas monitoring techniques
93. Integrating Gas Detection Techniques Tubes Single Gas: CO/O2/LEL Multigas CSE Broadband: MOS Selective: IMS Selective: GC/MS Selective: Tubes Broadband: PID/FID Gas Monitoring Pyramid Selectivity Increases as you move up the Pyramid The Answer
94. Integrating Gas Detection Techniques Tubes Single Gas: CO/O2/LEL Multigas CSE Broadband: MOS Selective: IMS Selective: GC/MS Selective: Tubes Broadband: PID/FID PID + Tubes Approximates the selectivity of GC/MS w/o the cost Gas Monitoring Pyramid The Answer