Evaluation of two methods for the calculation of the uncertainty in the determination of solids suspended total

Abstract

Objective. To determine the uncertainty of the mesure using two applied methods in the analysis of solids suspended total (SST) in residuals water of the Huallaga river in Huanuco (Peru). Methods. For comparison the versatility of two methods of determination of the uncertainty of an analytical measurement, in this case applied to the determination of SST in residuals water, An quantitative approach and of comparison of two methods of calculate: first, using the estimation of the sources of uncertainty more relevance (Cooperation on International Tarceability in Analitic Chemestry, EURACHEM/CITAC); and second, using the results estimation of the validation of an analytic method (Analitycal Methods Committee, Marotto). The samples considered as residuals water was toke of the Huallaga river (Joaquin Garay bridge), where this receive untreated wastewater discharges during the months of april to august of the 2023. For the determination of SST dried among 103 to 104 °C, the standardized method 2540D was used, while that for the analysis of data, descriptive statistics were obtained and a comparison test of means using Student's t distribution test was applied. Results. A relative uncertainty was obtained with the first method of the 6 % for a concentration of 234,8 mg/L and with the second method of the 10% to the concentration of 244,7 mg/L. Conclusion. To compare with other determinations, the uncertainty value obtained with the second method was approximated to the obtained in the references, with the advantage that its calculation is more simple