Determination of sliver,tin and boron in organic soil by alternating current arc optoelectronic direct reading emission spectrometry
The establishment of analysis method for silver,tin and boron in organic soil has importance sig-nificance for surface matrix investigation and evaluation projects.During the determination of organic soil samples containing relatively high content of carbon by alternating current arc optoelectric direct reading e-mission spectrometry,the problems such as unstable arc excitation and sample spattering are easily caused,influencing the accuracy of determination results.In this study,the sample was pretreated by high temperature ashing to remove organic carbon,then it was mixed with buffer agent followed by excitation with alternating current arc.Thus,a determination method of silver,tin and boron in organic soil was es-tablished by alternating current arc optoelectric direct reading emission spectrometry.The pretreatment conditions were optimized.The results showed that the pretreatment of sample by high temperature ashing at 600 ℃ for 2 h could significantly improve the stability of determination results.Moreover,it would not cause the loss of silver,tin and boron in sample.The exciting current was also optimized,and the follow-ing two-stage current excitation conditions were adopted:the arcing current for preexcitation was 4 A for 3 s,and then it increased to secondary current of 17 A for 22 s.The certified reference materials of silicate for spectral analysis were selected.The calibration curves were plotted by linear fitting with the strength ratio logarithm of analytical line after deducting the background as ordinate,and the concentration log-arithm as abscissa.The correlation coefficients of calibration curves were all no less than 0.999 5.The limits of detection for silver,tin and boron were 0.000 9,0.21 and 0.15 μg/g,respectively.The contents of silver,tin and boron in certified reference materials of soil were determined according to the proposed method,and the relative standard deviations(RSDs,n=12)of determination results were not more than 6.3％with logarithic deviation of determination results from theoretical value of AlgC≤0.049,which could meet the requirements of precision and trueness of method specified in industry standards of DZ/T 0258-2014 and DD 2005-01.The proposed method was applied to determination of silver,tin and boron in organic soil samples,and the RSDs(n=12)of determination results were between 3.4％and 4.9％.
alternating current arc emission spectrometryorganic soilsilvertinboron
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