1. CENTRO DE METROLOGIA QUIMICA

2. CALCULATION OF UNCERTAINTIES FOR THE REPORT OF ANALYSES IN SIM. 8. P1
CALCULATION OF UNCERTAINTIES FOR THE REPORT OF ANALYSES IN SIM.8.P1.2 (CHLORINATED PESTICIDES IN HEXANE) 1

3. ANALYTICAL MEASUREMENT
Gas Chromatograph
Perkin-Elmer Model 8000 series 2 with Electron Capture Detector and manual injector
Column Phase, BP- 5
Col. Length, m
Col. i.d., mm
Col. film thickness, µm
HEXACHLOROBENZENE
gamma-HCH (g-BHC, LINDANE)
HEPTACHLOR
HEPTACHLOR EPOXIDE
2,4'-DDE
CIS-CHLORDANE (ALPHA-CHLORDANE)
TRANS-NONACHLOR
DIELDRIN
4,4'-DDE
2,4'-DDD
2,4'-DDT
4,4'-DDT
MIREX 1

4. ANALYTICAL MEASUREMENT
NIST-SRM 2261 was used for the preparation of calibration standards.
The quantification method used was bracketing using the method of internal standard.
Sample of SIM.QM-P1 was selected as control 1

5. ANALYTICAL MEASUREMENT
GENERAL SCHEME OF ANALYTICAL MEASUREMENT
Gravimetric Preparation of standards, samples and controls
Gravimetric Preparation of dilution
Verification of the standards through the calibration curve
Determination by bracketing using the method of internal standard
Statistical evaluation of the results and uncertainty calculation 1

6. GRAVIMETRIC PREPARATION OF STANDARDS

7. BRACKETING SCHEME 120 58 40 20 8 4,4 ‘ -DDE
ng/g
120 58 40 20 8
4,4 ‘ -DDE
HCB, g-HCH, HEPTACLOR EPOXI, MIREX, 2’4-DDT, 4’4-DDT
DIELDRIN
HEPTACLOR (s/d), cis-CLORDANO, trans-NONACLOR, 2’4-DDD, 2’4-DDE 1

8. THE UNCERTAINTY ESTIMATION PROCESS

9. BRACKETING AND INTERNAL STANDARD
(AH/AIS)
(AS/AIS)
(AL/AIS)
CS/CIS
CH/CIS
CL/CIS
Sample concentration is calculated trough the equation: 1

10. IDENTYFYING UNCERTAINTY SOURCES
Csample

11. QUANTIFYING UNCERTAINTY SOURCES
Csample

12. UNCERTAINTY OF THE STANDARDS

13. UNCERTAINTY OF THE STANDARDS

15. GRAVIMETRIC PREPARATION OF STANDARDS
Ampoules SMR 2261
sol. INT 1
sol. INT 3
Standard
Brack
low
Brack high
IS – sol. INT
IS solid
0.5%
0.6%
0.6%
0.6%
0.6%

16. IDENTYFYING UNCERTAINTY SOURCES
Csample

17. IDENTYFYING UNCERTAINTY SOURCES
Csample

18. PURITY OF THE INTERNAL STANDARD
The purity of IS is quoted by the supplier as 99.0 % . The quoted uncertainty is taken as a rectangular distribution

19. QUANTIFYING UNCERTAINTY SOURCES

20. UNCERTAINTY STANDARD OF THE SIGNAL
The uncertainties associated with the variability of the area were estimated by making replicate measurements of samples and bracketing standards. These uncertainties are estimated through the following equation:

21. UNCERTAINTY STANDARD OF THE SIGNAL

22. QUANTIFYING UNCERTAINTY SOURCES

23. CALCULATING THE CONCENTRATION

25. UNCERTAINTY CONTRIBUTIONS

26. CONCENTRATION AND UNCERTAINTY VALUES FOR THE SAMPLE SIM.8.P1.2