Low-resolution mass spectrometric relative response factors (RRFs) and relative retention times (RRTs) on two common gas chromatographic stationary phases for 87 polychlorinated dibenzofurans.
2004 (English)In: Chemosphere, ISSN 0045-6535, Vol. 55, no 7, 983-95 p.Article in journal (Refereed) Published
All 87 tetra- to octa-chlorinated dibenzofurans (PCDFs) were analysed using high-resolution gas chromatography/low-resolution mass spectrometry (HRGC–LRMS). The mass spectrometer was operated in two different modes: electron ionisation (EI), and negative ion chemical ionisation (NCI) with methane as a reagent gas. Baseline separation and identification of all PCDF congeners was carried out using one non-polar (DB-5) and one polar (RT-2330) capillary GC column. Relative retention times (RRTs) on both columns, and relative response factors (RRFs) in both EI- and NCI-modes, were calculated for all 87 of the PCDFs. Comparison of the EI-RRFs and NCI-RRFs showed that the mass spectrometric NCI-responses varied to a higher degree than the EI-responses. The level of NCI-response was dependent on the substitution positions of the chlorine atoms on the dibenzofuran molecule skeleton. The ratio between the highest and lowest RRFs was 26 in the NCI-mode, but only 2.3 in the EI-mode. Thus, quantification of tetra- to octa-CDFs in environmental samples using the NCI-mode will result in incorrect estimates of PCDF concentrations unless 13C-labelled internal standards are used for each congener, or RRFs are taken into consideration. In contrast, the quantification of PCDFs in the EI-mode using a single internal 13C-labelled PCDF standard for each PCDF homologue is accurate according to the findings in this investigation. A flue gas sample from a municipal solid waste incinerator (MSWI) analysed in the NCI-mode was quantified with and without NCI-RRFs. When using NCI-RRFs the reported concentration of ∑PCDFs in the flue gas sample increased by 40%. Furthermore, TCDF analysis was compared using two mass spectrometers (a VG 12-250 and a Finnigan 4500) operating in EI-mode. These quadrupole instruments performed equally well, giving similar EI-RRFs for the tested compounds.
Author Keywords: Polychlorinated dibenzofurans (PCDFs); Relative response factors (RRFs); Relative retention times (RRTs); Electron ionisation (EI); Negative chemical ionisation (NCI)
Place, publisher, year, edition, pages
2004. Vol. 55, no 7, 983-95 p.
Benzofurans/*analysis/*chemistry, Carbon Isotopes, Comparative Study, Mass Fragmentography/*methods, Methane, Time Factors
IdentifiersURN: urn:nbn:se:umu:diva-5736DOI: doi:10.1016/j.chemosphere.2004.01.017PubMedID: 15051368OAI: oai:DiVA.org:umu-5736DiVA: diva2:145404