Determination of polychlorinated biphenyl congeners and chlorinated pesticides in a fish tissue standard reference material

Abstract

The concentrations of a wide range of polychlorinated biphenyl congeners (PCBs) and chlorinated pesticides in a fish tissue Standard Reference Material (SRM) have been determined using multiple methods of analysis. This material, SRM 1946, Lake Superior Fish Tissue, was recently issued by the National Institute of Standards and Technology (NIST) and complements a suite of marine environmental natural-matrix SRMs that are currently available from NIST for the determination of organic contaminants such as aliphatic hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), PCBs, and chlorinated pesticides. SRM 1946 is a fresh tissue homogenate (frozen) prepared from filleted adult lake trout (Salvelinus namaycush namaycush) collected from the Apostle Islands region of Lake Superior. SRM 1946 has certified and reference concentrations for PCB congeners, including the three non- ortho PCB congeners, and chlorinated pesticides. Certified concentrations are available for 30 PCB congeners and 15 chlorinated pesticides. Reference concentrations are available for 12 PCB congeners and 2 chlorinated pesticides. In addition, SRM 1946 is characterized for additional chemical constituents and properties: fatty acids, extractable fat, methylmercury, total mercury, selected trace elements, proximates, and caloric content. The characterization of chlorinated compounds is described in this paper with an emphasis on the approach used for the certification of the concentrations of PCB congeners and chlorinated pesticides. The PCB congener and chlorinated pesticide data are also compared to concentrations in other marine natural-matrix reference materials available from NIST (fish oil, mussel tissue, whale blubber, and a second fresh frozen fish tissue homogenate prepared from filleted adult lake trout collected from Lake Michigan) and from other organizations such as the National Research Council Canada (ground whole carp), the International Atomic Energy Agency (fish homogenate), and the European Commission Joint Research Centre [fish oils (cod and mackerel) and mussel tissue].

Cyclodextrin-Enhanced Extraction and Energy Transfer of Carcinogens in Complex Oil Environments

“…This energy transfer was most efficient for motor oil, vegetable oil, and pump oil (with 360 nm excitation), and least efficient for cod liver oil. This data is consistent with literature reports of some degree of PAH contamination in motor oil, vegetable oil, and pump oil, and no PAHs in cod liver oil, [29][30][31][32][33] and supports the idea that PAHs in the actual oils participate in cyclodextrin-promoted energy transfer. To ensure that the fluorophore peak defined as energy transfer was a result of actual energy transfer from the analyte to the fluorophore (rather than a result of the fluorophore having a non-zero absorbance at the analyte excitation wavelength), the fluorophore was excited at the excitation wavelength of the analyte (270 nm, 290 nm, and 360 nm) in the presence of the analyte and in the absence of the analyte.…”

“…The oils used in these investigations (vacuum pump oil, motor oil, vegetable oil, and cod liver oil) contain varying levels of PAH contaminants: from no known PAHs in cod liver oil, 29,30 to small amounts of PAHs in several types of vegetable oil, 31,32 and large quantities of PAHs in used motor oil. 33 These 'innate' PAH amounts were detected by measuring the energy transfer efficiencies from 'undoped' oil samples to the fluorophore.…”

Miniaturised sample preparation of fatty foodstuffs for the determination of polychlorinated biphenyls

“…More importantly, these recoveries were in the range of (or even better than) those previously published using more conventional multi-step procedures involving the extraction of larger amounts of sample by widely accepted extraction techniques, such as pressurised liquid extraction or Soxhlet extraction, followed by more exhaustive clean-up protocols for similar applications [14 -16 ( and references therein)]. The satisfactory relative standard deviation (RSD) values obtained using the onestep procedure (lower than 14%, n = 4), which were essentially the same than those found using the reference procedure irrespective of the sample size selected, also lay in the range of those previously reported by other authors leading with similar applications [5,15,17] and proved the accuracy of the method developed. As an additional illustration of the performance of the method developed, Table 2 compares the results obtained when the non-ortho-PCBs 77, 126, and 169 were analysed using the miniaturised procedure proposed combined with GC -ITD (MS/MS) and by the more conventional off-line large scale method quoted above involving 10 g of sample, the isolation of the non-ortho PCBs from the ortho-congeners, and the separate final determination of the former class of analytes by high resolution mass spectrometry (GC -HRMS) [8].…”

“…Lower recoveries were obtained only for PCB 194 at the 0.5 g level, 59%. Possible losses of the most volatile congeners during evaporation of the extraction solvent in the reference procedure [14,15] and/or coelution with interferences could be suggested as possible explanations for the higher levels obtained for some early eluting PCBs, such as congeners 52, 95, and 101, in the one-step approach as compared to the reference procedure. Nevertheless, satisfactory correlation coefficients (r 2 ) were obtained in all instances among the concentrations determined using the reference method and those calculated by the one-step procedure (r 2 = 0.991, when using 0.5 g of sample, and r 2 = 0.98, using 0.1 g), indicating good agreement among the analytical methodologies.…”

Three new mussel tissue standard reference materials (SRMs) for the determination of organic contaminants

“…The goal was to meet the need for a material that consisted of a matrix that was as close as possible to a natural tissue. By using a cryogenic homogenization procedure, one often applied to the preparation of materials for environmental specimen banking [2,3] and described by Zeisler [4], SRM 1974, Organics in Mussel Tissue (Mytilus edulis), was produced from mussels collected in Boston Harbor and became the first SRM in an array of fresh frozen natural-matrix materials ranging from whale blubber [5] to fish tissue [6] that followed suit.…”