Naslov
Determination of PCBs in oil: a proficiency test within the frame of AMOS project

Autori
Vasilić, Želimira ; Krauthacker, Blanka ; Drevenkar, Vlasta

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
AOAC International Central Europe Subsection, 5th Int.Symp.Interpretation of Chemical, Microbiological and Biological Results and the Role of Proficiency Testing in Accreditation of Laboratories, Book of Abstracts / Krauthacker, Blanka ; Raspor, Biserka - Zagreb : Inst. za med. istraž. i medicinu rada, Inst."Ruđer Bošković", 1998, P-27

Skup
AOAC International Central Europe Subsection, 5th Int.Symp.Interpretation of Chemical, Microbiological and Biological Results and the Role of Proficiency Testing in Accreditation of Laboratories

Mjesto i datum
Varaždin, Hrvatska, 21.10.1998. - 23.10.1998

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
PCB congeners in oil; international interlaboratory comparison

Sažetak
Through mediation of the Croatian State Office for Standardisation and Metrology the Institute for Medical Research and Occupational Health participated in an international interlaboratory comparison as to the determination of polychlorinated biphenyls (PCBs) in mineral oils. The intercomparison was organised by the Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany. The oil sample spiked with PCBs, PCB congener 209 as internal standard and standard mixtures for quantitative determination of PCB congeners 28, 52, 101, 138, 153, and 180 were provided through the BAM AMOS Proficiency Test (Akkreditierung und Zertifizierung in Mittel- und Osteuropa). The German standard DIN 51527 Part 1 was recommended as the appropriate analytical method but the use of other methods or modifications was also allowed. Because of statistical calculations, four independent results were demanded obtained by the analysis of separate weighing of oil sample. To calculate the statistical data for each participating laboratory, BAM used a proficiency testing scheme based on DIN ISO 57525 standard. They determined the mean value (Xi) and the standard deviation of each participant results and calculated for each parameter deviation in relation to an accepted mean value (Xmean) and an accepted reproducibility deviation (SR). Z-Scores were calculated according to Z = Xi - Xmean/SR equation. The results were accepted as correct if the participant measurements were inside the Z-score interval of -2 < Z < 2. In order to obtain a certificate, at least 80% of the results had to be within those limits. To determine the selected PCB congeners in oil we used a modification of the DIN 51527 method and omitted the complex liquid chromatography pre-separation and cleanup procedures on the combined benzenesulphonic/sulphuric acid and silica gel columns. Four sample solutions were prepared by dissolving 1.519 - 1.595 g of oil in 25 ml of n-hexane and further diluted 5-10 times with the same solvent. The 1.0-ml aliquots of diluted solutions were washed with 1.0 ml of concentrated sulphuric acid. The organic layer was separated and analysed by capillary gas chromatography using an electron capture detector. The samples were analysed concurrently on three different columns: a 60 m x 0.25 mm i.d. SPB-5 column, a 30 m x 0.25 mm i.d. SPB-5 column and a 30 m x 0.25 mm i.d. SPB-1701 column. The reported concentrations of PCB congeners in four independent samples were the mean values of the results obtained on all three columns. The calculated Xi values were 0.05, 0.36, 0.69, 0.49, 0.36 and 0.07 mg/kg for PCB 28, 52, 101, 138, 153, and 180, respectively. BAM excluded PCB 28 from the final statistical evaluation because of the concentration below the determination limit. The Z values for other PCB congeners were within the limit set by the proficiency test and ranged from -1.11 to -0.75. The Institute received a certificate confirming the successful participation in the interlaboratory comparison.

Izvorni jezik
Engleski

Znanstvena područja
Javno zdravstvo i zdravstvena zaštita

POVEZANOST RADA