Characteristics of atomic absorption calibration curves with the transversely heated graphite furnace

摘要: Calibration curves with two quasi-linear sections (“double sloping”) were observed for the medium volatile elements, Cr and Cu, use of a SIMAA 6000 graphite furnace atomic absorption spectrometer under interrupted internal gas flow conditions. If standard transversally heated atomizer (THGA) tube was shortened by 0.5 mm at both its ends, (i.e. gaps enlarged between housing ends), stronger declination calibration resulted. Elements fairly high diffusion coefficients (>5.8 cm2 s−1) short appearance time their transients (<0.6 s), such as have shown most characteristic sensitivity drop towards higher concentrations. This anomalous feature could be eliminated in three different ways; (1) applying end-capped THGA tubes, (2) using mini-flow (50 cm3 min−1) conditions during atomization stage, (3) adding Pd–Mg chemical modifier. For low Mo V, had no irregular shape. Ag, Co, Cr, Mn Ni, settings improved linearity extended upper limit linear range factor 1.5–2.0. The analytical interpreted an increased vapour loss analyte concentrations through opened ends tubes. associated significantly diverse expulsion velocities atoms, caused difference temperature concentration gradients, when evaporating amounts analytes more than one order magnitude difference.