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1 9. <br /> y <br /> 9 <br /> a+e <br /> j <br /> ' k <br /> The Photovac 10S50 is a <br /> chromato ra Portable' g programmable, integrating 9 Ph with a phataionization detector (PID) , The PIDas <br /> a non-destructive flow-through detector that uses high ener is <br /> ultraviolet radiation as its ionization source. Th gy <br /> radiation ionizes a high energy <br /> compounds, generating an energy increase in the <br /> ! <br /> detector which appears as an electrical signal., measured in <br /> volts. <br /> The instrument is calibrated with standards consist <br /> 10 ppm benzene and l0 ppm toluene g of <br /> �- each standard n air. For the reading of <br /> t , the instrument stores the known concentration and <br /> € - the volt-second (V-sec) response to it, <br /> The HNU 421 is a laboratory-size, temperature- ro <br /> chromatograph equipped P grammable gas <br /> 8 -- q Aped with a flame ionization detector <br /> g The hydrogen-air flame ionizes compounds, (FID) . <br /> ( increase in the detector, whichP ' generating an energy. <br /> t <br /> The instrument appears as an electrical signal. <br /> is operated isothermally at 600C and the capillar <br /> column <br /> flow. rate is <br /> 10 ml/min. These conditions ensure e y <br /> retention. time stability and <br /> - ¢' r� peak <br /> the columna the contaminant build-up within <br /> The instrument is calibrated with standards <br /> consisting .of known concentrations of benzene, toluene, <br /> and ehyzbenzene in air, Far the reading _ erie' 'xyl-enes, 9 <br /> ach <br /> instrument stores the known concentration andtheVtsecaresponse <br /> ? to -it in a Shimadzu F. <br /> 3 <br /> f C-R3A integrator <br /> standard g The' ratio for the <br /> .. V-sec:pPm, is then used to <br /> ..v.. <br /> Of <br /> identifiable vapors in field san�plesaaccor tity the concentrations <br /> �{ values. din to <br /> g their V-sec <br /> IA <br /> The .concentrations--of u- <br /> nidentified compounds are calculated ' <br /> simii <br /> ar. manner, <br /> Y Although petroleum hydrocarbon <br /> in a ;- <br /> � , instrumenal "res s produce,var' <br /> sable <br /> Ponses, the assum tion may r the hydrocarbon constit P y be made that all .of <br /> uents .have response-to-concentration <br /> ratios approximately equivalent to that of benzene and m �? <br /> quantifications that all <br /> --: may be based on the ratio for benzene, In' the. <br /> ' table of results <br /> ," the column entitled "peaks Prior to Benzene,, <br /> represents. the. sum of the response Ponses in V-sec for all peaks <br /> g Prior to benzene <br /> ,' proportioned to the calibrated V-sec <br /> EXXON9 t 8 4 L <br /> 9 <br /> J <br /> F <br /> v <br />