RESUMEN
<p><b>OBJECTIVE</b>To establish the method of graphite furnace atomic absorption spectrometry for the measurement of stannum in urine with calcium nitrate as the matrix modifier.</p><p><b>METHODS</b>Graphite tube was pretreated with calcium nitrate as the matrix modifier, the urine sample was diluted with 1% nitric acid and then direct injection was performed for these samples, and graphite furnace atomic absorption spectrometry was applied for measurement.</p><p><b>RESULTS</b>The concentration of stannum in urine showed a good linear relationship within the range of 8.0~40.0 μg/L, with a correlation coefficient of 0.9981. The minimum detectable concentration was 0.72 μg/L, the degree of precision was 1.54%~6.69%, and the recovery rate was 99.23%~107.63%.</p><p><b>CONCLUSION</b>This method can determine the content of stannum in urine accurately and rapidly, with a high sensitivity and a low cost.</p>