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GROUNDWATER TECHNOLOGY, INC. <br /> STANDARD OPERATING PROCEDURE <br /> CONCERNING OPERATION/CALIBRATION OF <br /> PHOTOIONIZATION ANALYZER <br /> SOP 19 <br /> 1 The Thermo Environmental Instruments Inc Model 580B OVM Photolonization Analyzer shall be <br /> used, using photoionization,to measure the concentration of trace gases over a range of less than <br /> 1 ppm to 2,000 ppm The specific Instrument used for investigations related to hydrocarbon <br /> contamination should be calibrated for direct readings In parts per million (ppm) volume/volume <br /> of isobutylene Specifics of the detection principle/theory and functions of various components can <br /> be found in the manufactures Instruction manual <br /> 2 To assure optimum performance,the photoionization analyzer should be calibrated with a standard <br /> gas mixture of known concentration from a pressurized container A daily procedure for calibration <br /> Involves bringing the probe and readout close to the calibration gas, cracking the valve on the tank <br /> and checking the Instrument reading This provides a useful spot check for the Instrument <br /> 3 A procedure conducted weekly for more accurate calibration of the instrument from a pressurized <br /> container is to connect one side of a T to the pressurized container of calibration gas,another side <br /> of the T to a rotameter and the third side of the T directly to the W extension to the <br /> photolonization probe(see Figure 2) Crack the valve of the pressurized container until a slight flow <br /> Is Indicated on the rotameter The Instrument draws In the volume of sample required for detection, <br /> and the flow in the rotameter Indicates an excess of sample Now adjust the span pot so that the <br /> Instrument reads the exact value of the calibration gas (If the instrument span setting Is changed, <br /> . the Instrument should be turned back to the standby position and the electronic zero should be <br /> readjusted, If necessary) <br /> GROUNDWATER <br /> [ __I TECHNOLOGY, INC <br />