Multi-residue analysis of polycyclic aromatic hydrocarbons, polychlorobiphenyls, and organochlorine pesticides in marine sediments

Abstract

A multi-residue analysis procedure using microwave-assisted extraction and pre-purification has been developed for the combined analysis of polycyclic aromatic hydrocarbons (PAH), polychlorobiphenyls (PCB), and organochlorine pesticides (OCP) in marine sediments. This procedure has been validated with certified marine sediment. Several surrogate standards have been employed and the use of octachloronaphthalene (OCN) as a surrogate standard for organochlorine determination in this matrix is discussed. The recoveries of all compounds were high (>70%) and the relative standard deviations are of the same order as the certified values. Different analytical problems are discussed, including DDT degradation in gas chromatography and laboratory PCB background levels. Quantification problems encountered for two pesticides (cis-chlordane and trans-nonachlor) were attributed to PAH interference in the GC-ECD chromatogram.

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

“…(As is well known, some coelution problems affect the determination of specific PCB congeners in DB-5 type GC columns [13,14]. However, as in this study all extracts have been analysed under similar experimental conditions, the sets of results summarised in Table 1 can be directly compared with one another.)…”

“…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.…”

“…These results indicated that the new miniaturised method could be a valuable fast and cost-effective alternative to the more classical analytical protocols typically used for sample preparation in this type of determination. (Nevertheless, it is worth mentioning that an extra isolation of the non-ortho congeners from the bulk of PCBs [8,14] would eliminate the need for careful optimisation of the GC conditions to avoid coelution of these planar compounds with other more abundant congeners. As an example, Figure Table 1 for peak identification.…”

Determination of organochlorine compounds in coastal marine sediments from the southern west of the Mediterranean Sea

“…This could be explained by their probable volatilization during storage and during analytical procedure. Indeed, the less chlorinated congeners are more volatile than the higher chlorinated congeners (Thompson et al, 2002). Futhermore, PCBs with a higher number of chlorine atoms are more stable in the marine environment since they undergo less readly enzymatique oxydation by bacteria (Abramowicz et al, 1993).…”

Multi-residue Analysis of 18 Organochlorine Pesticides in 10 Traditional Chinese Medicines by Gas Chromatography (GC)

“…To our knowledge, various components such as lipids are needed to be eliminated so as to permit a more definitive identification of pesticide residues and to minimize interfering effects on the gas chromatography (GC). To this end, various column chromatography using Florisil, 5,6) silica gel 7) and gel permeation 8) were popularly used in clearing procedure nowadays. However, due to the complexity in the matrixes of TCM, a better procedure may be desirable.…”