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f <br /> d <br /> GROUNDWATER TECIINOI,OGY <br /> STANDARD OPERATING PROCEDURE <br /> CONCERNING OPERATION/CALIBRATION Or <br /> P110TOIONIZATION ANALYZER <br /> �j SOP 1-9 <br /> The ITNU Model 101 Photoionixati <br /> used on Analyzer shall he <br /> to measure the concentration of trace gases over a <br /> range of Less thar. 1 ppm to 2,000 ppm by <br /> principle of Photoioemploying the <br /> nixation for detection, phe <br /> specific instrument used for investigations related to <br /> hydrocarbon contamination should be calibrated for <br /> direct readings in parts per million (ppnt) volurue/volume <br /> Of benzene. This portable field analyzer consists of <br /> two components (1 ) probe which contains a fan for moving <br /> air into the sensor, an ultraviolet light (provides <br /> ionization energy), an ionization chamber and signal <br /> amplifier (2) readout assembly which contains a k:att•ery, <br /> ion chamber bias, meter readout and control panel , <br /> i Specifics of the detection <br /> r <br /> of various and can befound lintthermanufacturesons <br /> instruction manual {fiNU Systems, Inc. ). <br /> To assure optimum performance, the photcionization analy- <br /> zer should be calibrated with a standard <br /> known concentration gas mixture of <br /> from a pressurized container_ A <br /> daily procedure for calibration involves bringing the <br /> probe and readout in close proximity to the calibration <br /> gas, cracking the valve on the tank and checking the <br /> instrument reading. This provides a useful spot check <br /> for the instrument. <br /> A procedure conducted weekly for ni <br /> cali <br /> tic... of the instrument front a pressurizedre auc•ontainerbrais~ <br /> to connect one side of a "T" to the pressurized container <br /> of calibr?tion gas, another side of the "T" to L rotameter <br /> and the third side of the "T" directly to tfje R" extension <br /> to the phot-ionization probe (see Figure 2) . Crack the <br /> valve of the pressurized container until a slight flow is <br /> indicated on the rotameter. The instrument draws in the <br /> volume (If sample required for detection, and the flow in <br /> the rotameter indicates an excess of sample, Now adjust <br /> the span pot so that the instrument is reading the exact <br /> =? value of the calibration gas. <br /> (If the <br /> setting is changed, the instrument should �beut�urnednback <br /> to the standby position and the electronic zero should <br /> )` be readjusted, if necessary) , <br /> IGROUNDWATER <br /> ._ i-f-ECHNOI-OGY,INC. <br /> CONSUL IlNG GROUNDWATER GEOLOG;STS <br />