This study was performed to search a optimal analyzing method of cadmium in whole-blood. Cadmium was determined by graphite furnace atomic absorption spectrometry(GFAAS). We investigated the effect of asking temperature on the absorbance of cadmium in a simple dilution(ten-fold) method with triton X-100 and matrix modifier methods treated with NH₄H₂PO₄(1 and 3%) and Pd(NO₃)₂(0.001 and 0.005%) as matrix modifier. We also compared the reported reference values of standard blood with values resulted from optimal analyzing conditions of this study.
In case of a simple dilution method, when asking temperature was set at 450℃, the absorbance of sample and background were 0.334±0.012 and 1.382±0.245, respectively. Background level was higher than the value(0,8) that can be corrected by D₂ background correction method. As asking temperature was rised to 500℃, the absorbance of sample and background were 0.178±0.008 and 0.711±0.223 respectively. The higher asking temperature(450℃-650℃) was, the lower the absorbance of sample was.
In case of a matrix modifier method with NH₄H₂PO₄(1 and 3%), when asking temperature was rised from 500℃ to 650℃, the absorbance of sample slightly changed. The absorbances of sample at 600℃ were 0.230±0.017 and 0.137±0.012, respectively. These values were larger than that of simple dilution method. But the absorbance of background was higher than the level that can be corrected by D₂ method.
In case of a matrix modifier method with Pd(NO₃)₂(0.001 and 0.005%), the absorbance of sample and background were higher than those of other methods and were stable and reproducible. When asking temperature was aver 550℃ the absorbance of sample was significantly decreased. In case of 0.005% Pd(NO₃)₂, carbon residue remained in graphite tube affected the absorbance of sample and background.
From these results, We propose that in case of a simple dilution(ten-fold) method with triton X-100 ashing temperature must be maintained below 400℃. In order to diminish the absorbance of background, the alternative method is attenuation of injection volume or multiplication of dilution ratio. We recommend Pd(NO₃)₂ than NH₄H₂PO₄ as a matrix modifier. In case of a matrix modifier method with Pd(NO₃)₂, aching temperature might be maintained below 550℃.
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