Uncertainty evaluation in the measurement of organics compounds Description of the methodology used for the analysis of chlorinated pesticides in hexane in the SIM intercomparison study performed by Organics Materials Division of CENAM,as an example for uncertainty measurement evaluation. Gas chromatography with electron capture detector (GC-ECD) was used for analysis of the samples and construction of the calibration curve. Alejandro Pérez Castorena

Uncertainty evaluation in the measurement of organics compounds Preparation of the working standard solution (containing all analytes) PREPARATION OF STANDARD FOR THE CC CRM´s CRM(SRM 2261) Hexane Cd1(HBC) Cd2(HBC) 1 HCB Lindano (g-HCH) Heptacloro E. de hepatcloro 2,4'-DDE Cis-clordano ... Mirex ... + 1 6 Istd PCB 103 2 PCB(103) + PREPARATION OF THE MULTIELEMENTAL INTERNAL STANDARD SOLUTION (Ga, Rh and Bi) and CALIBRATION CURVE Alejandro Pérez Castorena

Uncertainty evaluation in the measurement of organics compounds Recovery using CRM reproducibility Cs Linear regression model used for interpolationAccording with the ISO 11095 and (a) R is not significantly different from 1. No correction is applied (b) R is significantly from 1 and a correction for R is applied ( c ) R is sinficantly different form 1 but, for operational reasons, no correction for R is applied Alejandro Pérez Castorena

Uncertainty evaluation in the measurement of organics compounds Alejandro Pérez Castorena