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t C&T P e Four <br /> dethod 6- (EPA 3550/418.1) Total Petroleum Hydrocarbons by Infrared Spectrophotometry TPH-IR: . <br /> sonication extraction in. Freon 113 (1,1.2-tricnloro 1,2,2-tririuoroethane) is followed by quantitation � <br /> .sin infraredspectrophotometry. " -��.�.-,...�„„� --- <br /> F g Advantages: This is acost-effective method for quantitation of the <br /> =urn of all three hydrocarbon fractions;down to a detection limit of: mg�Kg,'This technique permits <br /> Ise of a relatively large sub-sample, thus, avoiding_-sub-sampling errors f_M§5d—iV ritages:`Thi`sl' <br /> achnique does not identify lrydrocarbon constituents and ft is subject to interference from endogenous r <br /> rganic <br /> soil constituents. Freon does not:olubiZfze sortie <br /> of..he lii- boilin oint aromatic_hyd_roca <br /> - �-_p p y gP -� <br /> on com orients.ilius.;th se.s ecfes ma not be detected.. T <br /> CO-M-PARING : @PL 9 7P", <br /> APPLES To ORANGES @jM1 <br /> At Curtis & Tompkins we have encountered Frequently soil samples believed to be contarzmi- <br /> Customers that insist our TPH results are in nated by petroleum hydrocarbons are split.into <br /> � ror when compared to the TPH results"gener- duplicates in the field prior to presentation to <br /> ated by another laboratory. However,;upon the..Iaborat6ry. This technique for creating <br />`urther (polite) discussion it often comes to light duplicates and evaluating laboratory perform- <br />:hat the TPH analysis performed by the other ante is Eine, if the hydrocarbon contamination <br />_aboratory is not the same one we used. Please and/or soil sample chosen for splitting is homo- <br /> inform us as to the TPH procedure of`choice for geneous. Unfortunately, many soil samples <br /> your analysis and we will be more than_ Happy reflect the non-homogeneity of the alluvial soils <br />� <br /> o oblige! Laboratories may insist that one encountered throughout the coastal regions of <br />-)articular method for TPH analysis iso the California and, in.turn, these varying soil char- <br /> correct method. However, local regulatory agen-. acteristics lend to unequal distribution of hydro- <br /> cies often have a preferred technique and ex- carbon contarnination.in soils. These!factors <br /> pect you to use it. Choose your TPH-method often wreak havoc to TPH duplicate data. and:is <br /> arefuily. compounded by the sub-sampling performed (in <br /> accordance with EPA methodologies) of the <br /> sample prior to analysis by the laboratory. For <br /> example. soil samples presented to the lab often <br /> exceed 500.grams of which only 10 grams are <br /> 4: : '• .E :zi:Ms :: :> ::.. use <br /> �«Sri¢xS;��fv. ., gr .•�:.'�ti+A; ,y',c-'.,' .2; .zcb'4::'c'�Z>tb£'Y':. ::2 d for the analysis. - <br /> :,;te.Af.::'o <br /> ::iW::::ti,'r,`.uri�`%iik•'T,•';C.:.+i,���' n•.� ..�'�^j:.:.n. ..'.:.�'::\N:� <br /> :?`:h>.:^-:•:'r.ac:,;: w:.xb.�,,;hir;9::." ,y., r..oi..,q.��:;;�:``h.4 <br /> r;.. :.r..,- ,.,)Y�vm:cv,:..t• v,..^'�S`."•`.v•r -..,r....: +.:�:;+.t�..;scd;:'e:;�• <br /> We encourage field duplicates as a means to . <br /> evaluate laboratory performance, but please <br /> factor in the homogeneity of the field sample <br /> when evaluating the results. <br /> A Ii <br />