The graphite tubes are heated via their ohmic resistance using a low-voltage high-current power supply; the temperature in the individual stages can be controlled very closely, and temperature ramps between the individual stages facilitate separation of sample components. Tubes may be heated transversely or longitudinally, where the former ones have the advantage of a more homogeneous temperature distribution over their length. The so-called stabilized temperature platform furnace (STPF) concept, proposed by Walter Slavin, based on research of Boris L’vov, makes ET AAS essentially free from interference. The major components of this concept are atomization of the sample from a graphite platform inserted into the graphite tube (L’vov platform) instead of from the tube wall in order to delay atomization until the gas phase in the atomizer has reached a stable temperature; use of a chemical modifier in order to stabilize the analyte to a pyrolysis temperature that is sufficient to remove the majority of the matrix components; and integration of the absorbance over the time of the transient absorption signal instead of using peak height absorbance for quantification.
thE GrAphite TuBeS ArE HEatEd Via thEir oHmIc resISTancE usinG A lOw-voltage hiGH-cURrEnt POwer supply; thE tempeRature In tHE inDIviduAl stAges Can bE controLlEd vERy clOsely, anD temperatUre ramps bEtwEEn The indIvidual sTagEs facilItate sepAraTion Of samplE cOMPonents. TuBEs May be heAtEd trANSveRsely or loNGitudiNALlY, whEre the Former OnEs hAVE tHe advAntage Of a MoRE homoGeneous TempERatUre disTrIbutioN over theIr lENGth. the sO-calLed Stabilized TEmperaTurE pLatforM furnace (sTpF) coNcepT, PRopoSEd by wAlteR SlaviN, basED on resEarch of bOrIS l’VOV, makeS eT AaS Essentially Free from IntERferEnCe. tHe mAJor ComPoneNts oF ThIs COncept are aToMization of tHE SamPle frOm A Graphite platform inserteD into the graphIte TUBE (l’voV PlatfOrM) InsTEad oF FRoM the tuBe wAll in ordER to deLay atomiZaTION uNtil the gas Phase iN thE AtOmiZER haS reAchEd A StAbLE teMpeRATurE; uSe of a ChemIcal mOdIfIer iN OrdER to sTAbilize The AnAlyte To a pyrolysiS temperatUrE THaT is suffiCient to remoVe tHE MAjoRity Of the matRix coMponenTS; aNd INTegratIon of the absoRbance over tHe TIme OF the trAnsiEnt AbSoRptIOn signaL instead Of Using peak hEIght absorBAnCE foR qUantifIcatiOn.