Transversely heated graphite tube

M. Hornung and V. Krivan, Determination of Trace Impurities in Tungsten by Direct Solid Sampling Using a Transversely Heated Graphite Tube. Anal. Chem. 1998, 70, 3444. 

The interest in assessing the presence of A1 in wines is often motivated by its ability to produce bad taste and clouding effects. In an attempt to improve the sensitivity of ET-AAS instrumentation with end-capped transverse heated graphite tubes (ECTHGTs) for A1 determination in Port wine, Almedia et al. [63] investigated the performance of several chemical modifiers. Compared with other commonly used and recommended chemical compounds, K2Cr207 turned out to be better in terms of sensitivity and reduction of blank levels. The concentrations of Al in real samples were relatively high in comparison with other metals and varied from 273 to 803 pg 1 1. 

Herzberg, J., et al., CARS Thermometry in a Transversely Heated Graphite Tube Atomizer Used in Atomic Absorption Spectrometry, Applied Physics, 61, 201, 1995. 

Memory effects caused by the condensation of the matrix and analyte on cooler graphite parts with a conventional, longitudinally heated graphite tube are minimized in the transverse heated graphite tube (Figure 52). 

The following benefits can be obtained by the transverse heated graphite tube and rapid heating (i) STPF conditions for interference-free analysis for all elements including the refractory elements like V, Ti, and Mo (ii) Time saving and simplified operating since no tube change is required for the determination of refractory elements (iii) Automatic multi-element analysis... 

Figure 50 Cross-section of the transverse heated graphite tube with integrated Uvov platform (4100 ZL graphite tube, Perkin Elmer Corp.)...

Figure 4 Transversely heated graphite tube with integrated platform and contacts.

FIG. 4. Schematic design of an electrothermal atomizer transversely heated graphite tube and graphite contacts (Courtesy of Perkin-Elmer). 

Aluminum is the third most abundant element in the Earth s crust, and its omnipresence, e.g. in dust, results in an extremely high risk of contamination, particularly when traces of this element have to be determined. The most sensitive analytical line for aluminum is at 309.271 nm with a characteristic concentration of cq = 0.37 mg/L in a nitrous oxide / acetylene flame, which is about a factor of two better than what is obtained in LS AAS. The characteristic mass at this line, using a transversely heated graphite tube atomizer, is... 

The most sensitive analytical line for arsenic is at 193.696 nm at the beginning of vacuum-UV with a characteristic concentration of cq = 0.6mg/L in an air/acetylene flame. The characteristic mass at this line, using a transversely heated graphite tube atomizer, is mo = 50 pg. 

The most sensitive analytical line for lithium is at 670.785 nm with a characteristic concentration of Co = 0.006 mg/L in an air/acetylene flame, and a linear working range up to about Ara x = 3 mg/L. The characteristic mass at this line, using a transversely heated graphite tube atomizer, is mo = 1 pg. The lithium line at 670.785 nm is actually a doublet with a separation of about 15 pm, and it also exhibits an isotope shift of the same magnitude [150]. However line broadening in conventional atomizers is usually too pronounced, so that the individual fine structure components cannot be resolved. 

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