M. Taddia et al., DETERMINATION OF TIN IN INDIUM-PHOSPHIDE BY ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRY AND INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY, Journal of analytical atomic spectrometry, 8(5), 1993, pp. 755-758
Two independent methods for the determination of tin in tin-doped indi
um phosphide were developed and compared. The electrothermal atomic ab
sorption spectrometry (ETAAS) method utilized both platform atomizatio
n and a chemical modifier composed of orthophosphoric acid and magnesi
um nitrate. The detection limit (6s(b)) is 5.0 mug g-1 for a 250 mg sa
mple. The inductively coupled plasma mass spectrometry (ICP-MS) method
monitored the Sn-120 isotope and a typical detection limit (6s(b)) of
0.5 mug g-1 for a 20 mg sample was obtained. The observed range is 0.
2-0.75 mug g-1 depending on the instrumental stability and response. T
he matrix effect was investigated in both methods, and the results ind
icated that matrix-matched calibration standards should be used. Indiu
m phosphide wafers, obtained from a single crystal grown from a tin-do
ped melt, were analysed by using both methods to determine the tin con
tent and the change in concentration along the crystal. Results having
means that did not differ significantly (P=0.05) were achieved. Both
the ETAAS and ICP-MS techniques were useful in determining tin in the
tin-doped InP, however ICP-MS without internal standardization was les
s precise. When real samples containing 35-149 mug g-1 of Sn were anal
ysed, the relative standard deviation was in the range 12.9-4.3% for I
CP-MS and 3.4-2.0% for ETAAS.