RESUMO
ObjectiveTo evaluate the uncertainty for the determination of ethanol in human blood by auto-headspace gas chromatography (HS-GC) with internal standard curve method.Methods Each source of uncertainty, arising from the procedure of testing, was analyzed and conifrmed according to the guidelines of the uncertainty in measurement . After each uncertainty component was quantized, the combined standard uncertainty and the expanded uncertainty of the result were calculated.Results The relative uncertainty brought from the measurement repeatability, standard solution of the ethanol, the sample of blood, internal standard solution of the tert-butyl alcohol, the calibration cure, gas chromatography were 3.4%,0.71%,0.61%,0.41%,1.1% and 1.3% respectively; the relative expanded uncertainty of ethanol in blood was 3.9%.Conclusion The measurement uncertainty of the concentration of ethanol was came primarily from the measurement repeatability of sample, HS-GC and standard curve of ethanol.